Efforts to achieve the Millennium Development Goals (MDGs) to improve maternal and child health can be accelerated by addressing preterm birth and stillbirth. However, most global health stakeholders are unaware of the inextricable connections of these adverse pregnancy outcomes to maternal, newborn and child health (MNCH). Improved visibility of preterm births and stillbirths will help fuel investments and strengthen commitments in the discovery, development and delivery of low-cost solutions globally. This article addresses potential barriers and opportunities to increasing global awareness and understanding.
Qualitative research was conducted to analyze current knowledge, attitudes and commitments toward preterm birth and stillbirth; identify advocacy challenges; and learn more about examples of programs that successfully advocate for research and appropriate interventions. Forty-one individuals from 14 countries on six continents were interviewed. They included maternal, newborn, and child health advocates and implementers, United Nations agency representatives, policymakers, researchers, and private and government donors.
A common recognition of three advocacy challenges with regard to preterm birth and stillbirth emerged from these interviews: (1) lack of data about the magnitude and impact; (2) lack of awareness and understanding; and (3) lack of low-cost, effective and scalable interventions. Participants also identified advocacy opportunities. The first of these opportunities involves linking preterm birth and stillbirth to the MDGs, adding these outcomes to broader global health discussions and advocacy efforts, and presenting a united voice among advocates in the context of broader MNCH issues when addressing preterm birth and stillbirth. Another key opportunity is putting a human face to these tragedies—such as a parent who can speak to the personal impact on the family. Lastly, several interviewees suggested identifying and engaging champions to garner additional visibility and strengthen efforts. Ideal champions will work collaboratively with these and other maternal, newborn and child health issues. Conclusion: Advocacy efforts to add preterm births and stillbirths to broader MNCH goals, such as the MDGs, and to identify champions for these issues, will accelerate interdisciplinary efforts to reduce these adverse outcomes. The next article in this report presents an overview of related ethical considerations.
Interventions directed toward mothers before and during pregnancy and childbirth may help reduce preterm births and stillbirths. Survival of preterm newborns may also be improved with interventions given during these times or soon after birth. This comprehensive review assesses existing interventions for low- and middle-income countries (LMICs).
Approximately 2,000 intervention studies were systematically evaluated through December 31, 2008. They addressed preterm birth or low birth weight; stillbirth or perinatal mortality; and management of preterm newborns. Out of 82 identified interventions, 49 were relevant to LMICs and had reasonable amounts of evidence, and therefore selected for in-depth reviews. Each was classified and assessed by the quality of available evidence and its potential to treat or prevent preterm birth and stillbirth. Impacts on other maternal, fetal, newborn or child health outcomes were also considered. Assessments were based on an adaptation of the Grades of Recommendation Assessment, Development and Evaluation criteria.
Most interventions require additional research to improve the quality of evidence. Others had little evidence of benefit and should be discontinued. The following are supported by moderate- to high-quality evidence and strongly recommended for LMICs:
• Two interventions prevent preterm births—smoking cessation and progesterone
• Eight interventions prevent stillbirths—balanced protein energy supplementation, screening and treatment of syphilis, intermittant presumptive treatment for malaria during pregnancy, insecticide-treated mosquito nets, birth preparedness, emergency obstetric care, cesarean section for breech presentation, and elective induction for post-term delivery
• Eleven interventions improve survival of preterm newborns—prophylactic steroids in preterm labor, antibiotics for PROM, vitamin K supplementation at delivery, case management of neonatal sepsis and pneumonia, delayed cord clamping, room air (vs. 100% oxygen) for resuscitation, hospital-based kangaroo mother care, early breastfeeding, thermal care, and surfactant therapy and application of continued distending pressure to the lungs for respiratory distress syndrome
The research paradigm for discovery science and intervention development must be balanced to address prevention as well as improve morbidity and mortality in all settings. This review also reveals significant gaps in current knowledge of interventions spanning the continuum of maternal and fetal outcomes, and the critical need to generate further high-quality evidence for promising interventions.
Preterm birth is the leading cause of all infant mortality. In 2004, 12.5% of all births were preterm. In order to understand preterm labor, we must first understand normal labor. Since many of the myometrial changes that occur during pregnancy are similar in mice and humans and mouse gestation is short, we have studied the uterine genes that change in the mouse during pregnancy. Here, we used microarray analysis to identify uterine genes in the gravid mouse that are differentially regulated in the cyclooxygenase-1 knockout mouse model of delayed parturition.
Gestational d18.0 uteri (n = 4) were collected from pregnant wild-type and cyclooxygenase-1 knockout mice. Part of the uterus was used for frozen sections and RNA was isolated from the remainder. Microarray analysis was performed at the Indiana University School of Medicine Genomic Core and analyzed using the Microarray Data Portal. Northern analysis was performed to confirm microarray data and the genes localized in the gravid uterus by in situ hybridization.
We identified 277 genes that are abnormally expressed in the gravid d18.0 cyclooxygenase-1 knockout mouse. Nine of these genes are also regulated in the normal murine uterus during the last half of gestation. Many of these genes are involved in the immune response, consistent with an important role of the immune system in parturition. Expression of 4 of these genes; arginase I, IgJ, Tnfrsf9 and troponin; was confirmed by Northern analysis to be mis-regulated during pregnancy in the knockout mouse. In situ hybridization of these genes demonstrated a similar location in the gravid wild-type and Cox-1 knockout mouse uteri.
To our knowledge, this is the first work to demonstrate the uterine location of these 4 genes in the mouse during late pregnancy. There are several putative transcription factor binding sites that are shared by many of the 9 genes identified here including; estrogen and progesterone response elements and Ets binding sites. In summary, this work identifies 9 uterine murine genes that may play a role in parturition. The function of these genes is consistent with an important role of the immune system in parturition.
Patients presenting with an episode of preterm labor that subsides in response to tocolysis and who subsequently deliver at term are considered to have false preterm labor. However, the episode of “preterm labor” may represent the uterine response (i.e., uterine contractions) to an insult that was not severe enough to trigger preterm parturition but which may put the fetus at risk for additional pregnancy complications including growth restriction. The objective of this study was to compare the frequency of small for gestational age (SGA) neonates among patients with an episode of increased uterine contractility who delivered at term and those who delivered preterm.
This retrospective cohort study included 849 patients. Inclusion criteria were: 1) regular uterine contractions that required hospitalization; 2) intact membranes; 3) gestational age between 20 and 36 weeks. SGA was defined as a birth weight <10th percentile for gestational age. Placental pathology was reviewed and the results were used to classify patients into an inflammatory cluster, vascular cluster or both. Contingency tables, Mann-Whitney U test, and multivariate logistic regression were used for statistical analyses. A p-value of <0.05 was considered significant.
1) The prevalence of SGA neonates in the study population was 16.1% (124/772); 2) patients who delivered at term had a significantly higher frequency of SGA neonates than those who delivered preterm [21.5% (64/298) vs. 12.7% (60/474); p=0.001]; 2) the results of placental pathology were available in 63.7% (492/772) of patients. Patients who delivered at term had a higher frequency of fetal or maternal vascular lesions without histologic evidence of inflammation than those who delivered preterm [29.1 % (43/148) vs. 18.9% (65/344); p=0.01]; and 3) term delivery after an episode of regular preterm uterine contractions was associated with an odds ratio of 2.22 (95% CI: 1.28-3.85) to deliver an SGA neonate after controlling for confounding variables. A sub-analysis limited to patients who received tocolysis showed similar results.
1) patients with an episode of increased uterine contractility that subsided and delivered at term are at risk for delivering an SGA neonate; 2) this suggests that an episode of false preterm labor is not a benign condition; and 3) we propose that insults to the feto-placental unit may be resolved by either irreversible preterm parturition or restricting fetal growth.
increased uterine contractility; intact membranes; small for gestational age; placental pathology; vascular cluster; inflammatory cluster; term delivery
The onset of preterm labor has been proposed to have survival value and to be adaptive in nature. This hypothesis would predict that induced preterm birth may be associated with higher rates of complications than spontaneous preterm birth. The purpose of this study was to determine if there is a difference in the frequency of neonatal respiratory distress syndrome (RDS), the most common neonatal complication, according to the etiology of preterm birth (e.g. preterm labor [PTL], preterm PROM, or pregnancies which ended because of maternal-fetal indications).
The relationship between the occurrence of RDS and the obstetrical circumstances leading to preterm birth was examined in 257 consecutive singleton preterm births (gestational age: 24-32 weeks). Cases with major congenital anomalies were excluded. The study population was divided into two groups according to the cause of preterm birth: 1) preterm birth due to PTL with intact membranes or preterm PROM (spontaneous preterm birth group); and 2) preterm birth due to maternal or fetal indications (indicated preterm birth group).
1) RDS was diagnosed in 47% of cases; 2) RDS was more common in patients with indicated preterm birth than in those with spontaneous preterm birth group (58.1% vs. 38.4%, p=.002); 3) Patients with indicated preterm birth had a significantly higher mean gestational age at birth, but lower mean birth weight, lower rate of histological chorioamnionitis and higher rates of cesarean delivery, 5 min Apgar score of <7, and umbilical arterial blood pH of <7.15 than those with spontaneous preterm birth (p<0.05 for each); 4) Antenatal corticosteroids were used in 73.4% of cases with indicated preterm birth and in 76.9% of those with spontaneous preterm birth; 5) Multivariate analysis demonstrated that indicated preterm birth was associated with an increased risk of RDS after adjustment for confounding variables (OR=2.29, 95% CI 1.22-4.29).
1) The rate of RDS is greater following “indicated” rather than spontaneous preterm birth; 2) This observation supports the view that spontaneous preterm labor is adaptive in nature.
Indicated preterm birth; neonatal respiratory distress syndrome (RDS); spontaneous preterm birth
Preterm labor is defined as labor that begins before 37 completed weeks of pregnancy. More than 12% of infants born in the USA are preterm. At least 40% of preterm births are associated with intrauterine infection. Toll-like receptors (TLRs) are members of a family of cell-surface proteins responsible for recognition of a diverse spectrum of bacterial, viral and fungal pathogens. TLRs initiate the host innate (i.e. non-adaptive) immune response, inducing a proinflammatory cascade involving cytokines, chemokines, prostaglandins, and other effector molecules that result in the characteristic phenomena of labor, such as uterine contractions and rupture of fetal membranes. These cascades may also be activated by mechanisms that are not primarily infectious but are accompanied by inflammatory responses. Now that the molecular mechanisms linking infection and labor have been, to a large extent, elucidated, the challenge is to identify points of overlap with non-infectious causes of labor and to find intervention strategies that can minimize the negative impact of preterm delivery.
Chorioamnionitis; Cytokines; Preterm delivery; Preterm rupture of membranes; Toll-like receptor
Preterm birth has the highest mortality and morbidity of all pregnancy complications. The burden of preterm birth on public health worldwide is enormous, yet there are few effective means to prevent a preterm delivery. To date, much of its etiology is unexplained, but genetic predisposition is thought to play a major role. In the upcoming year, the international Preterm Birth Genome Project (PGP) consortium plans to publish a large genome wide association study in early preterm birth. Genome-wide association studies (GWAS) are designed to identify common genetic variants that influence health and disease. Despite the many challenges that are involved, GWAS can be an important discovery tool, revealing genetic variations that are associated with preterm birth. It is highly unlikely that findings of a GWAS can be directly translated into clinical practice in the short run. Nonetheless, it will help us to better understand the etiology of preterm birth and the GWAS results will generate new hypotheses for further research, thus enhancing our understanding of preterm birth and informing prevention efforts in the long run.
Despite the substantial global burden of preterm and stillbirth, little attention has been given to the ethical considerations related to research and interventions in the global context. Ethical dilemmas surrounding reproductive decisions and the care of preterm newborns impact the delivery of interventions, and are not well understood in low-resource settings. Issues such as how to address the moral and cultural attitudes surrounding stillbirths, have cross-cutting implications for global visibility of the disease burden. This analysis identifies ethical issues impacting definitions, discovery, development, and delivery of effective interventions to decrease the global burden of preterm birth and stillbirth.
This review is based on a comprehensive literature review; an ethical analysis of other articles within this global report; and discussions with GAPPS's Scientific Advisory Council, team of international investigators, and a community of international experts on maternal, newborn, and child health and bioethics from the 2009 International Conference on Prematurity and Stillbirth. The literature review includes articles in PubMed, Academic Search Complete (EBSCO), and Philosopher's Index with a range of 1995-2008.
Advancements in discovery science relating to preterm birth and stillbirth require careful consideration in the design and use of repositories containing maternal specimens and data. Equally important is the need to improve clinical translation from basic science research to delivery of interventions, and to ensure global needs inform discovery science agenda-setting. Ethical issues in the development of interventions include a need to balance immediate versus long-term impacts—such as caring for preterm newborns rather than preventing preterm births. The delivery of interventions must address: women's health disparities as determinants of preterm birth and stillbirth; improving measurements of impact on equity in coverage; balancing maternal and newborn outcomes in choosing interventions; and understanding the personal and cross-cultural experiences of preterm birth and stillbirth among women, families and communities.
Efforts to improve visibility, funding, research and the successful delivery of interventions for preterm birth and stillbirth face a number of ethical concerns. Thoughtful input from those in health policy, bioethics and international research ethics helped shape an interdisciplinary global action agenda to prevent preterm birth and stillbirth.
To identify possible prepregnancy risk factors for antepartum stillbirth and determine if these factors identify women at higher risk for term stillbirth.
This retrospective cohort study of prepregnancy risk factors compared 712 singleton antepartum stillbirths to 174,097 singleton live births at or after 23 weeks of gestation. The risk of term antepartum stillbirth was then assessed in a subset of 155,629 singleton pregnancies.
In adjusted multivariable analyses, black race, Hispanic ethnicity, maternal age 35 years or older, nulliparity, prepregnancy body mass index (BMI) 30 kg/m2 or higher, preexisting diabetes, chronic hypertension, smoking, and alcohol use were independently associated with stillbirth. Prior cesarean delivery and history of preterm birth were associated with increased stillbirth risk in multiparas. The risk of a term stillbirth for women who were white, 25–29 years old, normal weight, multiparous, no chronic hypertension, and no preexisting diabetes was 0.8 per 1,000. Term stillbirth risk increased with these conditions: preexisting diabetes (3.1 per 1,000), chronic hypertension (1.7 per 1,000), black race (1.8 per 1,000), maternal age 35 years or older (1.3 per 1,000), BMI 30 kg/m2 or higher, (1/1000) and nulliparity (0.9 per 1,000).
There are multiple independent risk factors for antepartum stillbirth. However, the value of individual risk factors of race, parity, advanced maternal age (35– 39 years old) and BMI to predict term stillbirth is poor. Our results do not support routine antenatal surveillance for any of these risk factors when present in isolation.
Pregnancy and childbirth represent a critical time period when a woman can be reached through a variety of mechanisms with interventions aimed at reducing her risk of a preterm birth and improving her health and the health of her unborn baby. These mechanisms include the range of services delivered during antenatal care for all pregnant women and women at high risk of preterm birth, services provided to manage preterm labour, and workplace, professional and other supportive policies that promote safe motherhood and universal access to care before, during and after pregnancy. The aim of this paper is to present the latest information about available interventions that can be delivered during pregnancy to reduce preterm birth rates and improve the health outcomes of the premature baby, and to identify data gaps. The paper also focuses on promising avenues of research on the pregnancy period that will contribute to a better understanding of the causes of preterm birth and ability to design interventions at the policy, health care system and community levels. At minimum, countries need to ensure equitable access to comprehensive antenatal care, quality childbirth services and emergency obstetric care. Antenatal care services should include screening for and management of women at high risk of preterm birth, screening for and treatment of infections, and nutritional support and counselling. Health workers need to be trained and equipped to provide effective and timely clinical management of women in preterm labour to improve the survival chances of the preterm baby. Implementation strategies must be developed to increase the uptake by providers of proven interventions such as antenatal corticosteroids and to reduce harmful practices such as non-medically indicated inductions of labour and caesarean births before 39 weeks of gestation. Behavioural and community-based interventions that can lead to reductions in smoking and violence against women need to be implemented in conjunction with antenatal care models that promote women's empowerment as a strategy for reducing preterm delivery. The global community needs to support more discovery research on normal and abnormal pregnancies to facilitate the development of preventive interventions for universal application. As new evidence is generated, resources need to be allocated to its translation into new and better screening and diagnostic tools, and other interventions aimed at saving maternal and newborn lives that can be brought to scale in all countries.
This article is part of a supplement jointly funded by Save the Children's Saving Newborn Lives programme through a grant from The Bill & Melinda Gates Foundation and March of Dimes Foundation and published in collaboration with the Partnership for Maternal, Newborn and Child Health and the World Health Organization (WHO). The original article was published in PDF format in the WHO Report "Born Too Soon: the global action report on preterm birth" (ISBN 978 92 4 150343 30), which involved collaboration from more than 50 organizations. The article has been reformatted for journal publication and has undergone peer review according to Reproductive Health's standard process for supplements and may feature some variations in content when compared to the original report. This co-publication makes the article available to the community in a full-text format.
To determine factors associated with racial disparities in stillbirth risk.
Stillbirth hazard was analyzed using 5,138,122 singleton gestations from National Center of Health Statistics perinatal mortality and birth files, 2001-2002.
Black women have 2.2 fold increased risk of stillbirth compared to white women. The black/white disparity in stillbirth hazard at 20-23 weeks is 2.75, decreasing to 1.57 at 39-40 weeks. Higher education reduced the hazard for whites more than for blacks and Hispanics. Medical, pregnancy and labor complications accounted for 30% of the hazard in blacks and 20% in whites and Hispanics. Congenital anomalies and small for gestational age contributed more to preterm stillbirth risk among whites than blacks. Pregnancy and labor conditions contributed more to preterm stillbirth risk among blacks than whites.
The excess stillbirth risk for blacks was greatest at preterm gestations, and factors contributing to stillbirth risk vary by race and gestational age.
Stillbirth; racial disparity
To assess the efficacy of oral ritodrine in the form of sustained-release capsules for maintenance of uterine quiescence after successful treatment of threatened preterm labor.
We randomized 120 women with singleton pregnancy who were successfully treated for threatened preterm labor before 34 completed weeks to receive either maintenance tocolysis with two 40 mg ritodrine sustained release capsules three times a day (study group, n = 62) or no treatment (control group, n = 58) for three days. The primary outcome measure was the recurrent episode of threatened preterm labor within 72 hours, which was defined as regular palpable uterine contractions and change in cervical effacement or cervical dilatation on clinical examination. Secondary outcome measures included the incidence of preterm birth, neonatal adverse outcomes, and maternal side effects.
There was no difference in the frequency of recurrent episodes of threatened preterm labor requiring another course of intravenous treatment between the study (8/62) and control (6/58) group of women (P = 0.879). No differences were found between the study and control groups in any of the predefined secondary outcome measures, ie, delivery before 37 weeks (13/62 vs 7/58, respectively; P = 0.288), delivery before 34 weeks (3/62 vs 1/58, respectively; P = 0.682) and birth weight (3037 ± 573 g vs 3223 ± 423 g, respectively, P = 0.862). There were more reported maternal side effects in the study group than in control group (47/62 vs 23/58, respectively; P<0.001).
Additional maintenance ritodrine therapy was unnecessary in women with singleton pregnancy who had an episode of threatened preterm labor successfully treated with intravenous tocolytic therapy.
Clinical Trial Registration
ClinicalTrials.gov Identifier: NCT00290173
Premature birth is the world’s leading cause of neonatal mortality with worldwide estimates indicating 11.1% of all live births were preterm in 2010. Preterm birth rates are increasing in most countries with continual differences in survival rates amongst rich and poor countries. Preterm birth is currently an important unresolved global issue with research efforts focusing on uterine quiescence and activation, the ‘omics’ approaches and implementation science in order to reduce the incidence and increase survival rates of preterm babies. The journal Reproductive Health has published a supplement entitled Born Too Soon which addresses factors in the preconception and pregnancy period which may increase the risk of preterm birth and also outlines potential interventions which may reduce preterm birth rates and improve survival of preterm babies by as much as 84% annually. This is critical in order to achieve the Millennium Development Goal (MDG 4) for child survival by 2015 and beyond.
Urogenital infections are extremely prevalent during pregnancy and are an important cause of premature labor. However, the prevalence of urogenital infections during childbirth is not well known. Objective. Identify urogenital infections present at the beginning of labor in both full-term and preterm pregnancies. Study Design. Ninety-four women were admitted to the inpatient maternity clinic of the Federal University of Rio Grande do Norte (UFRN). In total, 49 women in preterm labor and 45 women in full-term labor were included in the study, and samples of urinary, vaginal, and perianal material were collected for microbiological analysis. Results. The prevalences of general infections in the preterm labor group and the full-term labor group were 49.0% and 53.3% (P = 0.8300), respectively. Urogenital infections in the preterm and full-term labor groups included urinary tract infection in 36.7% and 22.2% of women, vaginal candidiasis in 20.4% and 28.9% of women, bacterial vaginosis in 34.7% and 28.9% of women, and group B streptococcus in 6.1% and 15.6% of women, respectively. Conclusions. Urogenital infections were prevalent in women in preterm labor and full-term labor; however, significant differences between the groups were not observed.
Preterm parturition is a syndrome caused by several mechanisms of disease, including intrauterine infection/inflammation, uteroplacental ischemia, uterine overdistension, cervical disease, maternal/fetal stress, abnormal allogeneic responses, allergic reactions, and unknown insults. An allergic-like mechanism was proposed as a potential etiology for the preterm parturition syndrome, based on the observation that eosinophils were present in the amniotic fluid in a fraction of women with preterm labor and a history of allergy, coupled with the observation that conditioned media from degranulated mast cells (the effector cells of type 1 hypersensitivity) induced contractility of human myometrial strips. This communication describes a case of a pregnant woman who had an allergic reaction and regular uterine contractions after the ingestion of lobster meat, to which she was known to be allergic. Preterm labor subsided after the treatment of antihistamines and steroids. The patient subsequently delivered at term. At follow-up, the child was diagnosed with atopy and asthma, and required frequent use of inhaled corticosteroids and beta-2 adrenergic agents.
Allergy; preterm delivery; preterm birth; eosinophils; uterine allergy; pregnancy; preterm parturition; seafood; hypersensitivity; atopy; gestation; parturition; labor; allergic reaction
Management of preterm labor by tocolysis remains an unmet medical need. Prostaglandins play a major role in regulation of uterine activity and in molecular mechanisms of human labor and parturition. There is some circumstantial evidence that prostaglandin F2α by action through the prostaglandin receptor subtype FP is effective in key events during labor uterine contraction, rupture of membranes and cervical dilation. This role of FP is briefly reviewed. In this study, we tested the hypothesis that an orally active and selective FP antagonist may arrest labor and delay parturition in animal models.
We examined the effects of a small molecule selective antagonist of the FP receptor (AS604872) in inhibition of spontaneous uterine contraction in pregnant rat near term. We tested AS604872 for its ability to delay preterm birth in a mouse model in which the anti-progestin agent RU486 triggered parturition.
By oral or intravenous dosing AS604872 reduced markedly and dose-dependently the spontaneous uterine contractions in late-term pregnant rats at gestational days 19–21. In pregnant mice, AS604872 delayed the preterm birth caused by RU486 administration. The effect was dose-dependent with a significant increase in the mean delivery time of 16 and 33 hours at oral doses of 30 mg/kg and 100 mg/kg, respectively, in the case of labor triggered at gestational day 14. In both models AS604872 appeared more effective than the β-agonist ritodrine.
The tocolytic activity displayed by a selective FP receptor antagonist supports a key role for the FP receptor in the pathophysiology of premature birth and demonstrates the therapeutic potential of an FP antagonist for the treatment of preterm labor cases in which uterine hyperactivity plays a dominant role.
This is the first of seven articles from a preterm birth and stillbirth report. Presented here is an overview of the burden, an assessment of the quality of current estimates, review of trends, and recommendations to improve data.
Few countries have reliable national preterm birth prevalence data. Globally, an estimated 13 million babies are born before 37 completed weeks of gestation annually. Rates are generally highest in low- and middle-income countries, and increasing in some middle- and high-income countries, particularly the Americas. Preterm birth is the leading direct cause of neonatal death (27%); more than one million preterm newborns die annually. Preterm birth is also the dominant risk factor for neonatal mortality, particularly for deaths due to infections. Long-term impairment is an increasing issue.
Stillbirths are currently not included in Millennium Development Goal tracking and remain invisible in global policies. For international comparisons, stillbirths include late fetal deaths weighing more than 1000g or occurring after 28 weeks gestation. Only about 2% of all stillbirths are counted through vital registration and global estimates are based on household surveys or modelling. Two global estimation exercises reached a similar estimate of around three million annually; 99% occur in low- and middle-income countries. One million stillbirths occur during birth. Global stillbirth cause-of-death estimates are impeded by multiple, complex classification systems.
Recommendations to improve data
(1) increase the capture and quality of pregnancy outcome data through household surveys, the main data source for countries with 75% of the global burden; (2) increase compliance with standard definitions of gestational age and stillbirth in routine data collection systems; (3) strengthen existing data collection mechanisms—especially vital registration and facility data—by instituting a standard death certificate for stillbirth and neonatal death linked to revised International Classification of Diseases coding; (4) validate a simple, standardized classification system for stillbirth cause-of-death; and (5) improve systems and tools to capture acute morbidity and long-term impairment outcomes following preterm birth.
Lack of adequate data hampers visibility, effective policies, and research. Immediate opportunities exist to improve data tracking and reduce the burden of preterm birth and stillbirth.
Preterm birth remains a major cause of perinatal mortality and long term handicap in surviving infants. This is one of the most important clinical problems in Europe and across the world. While some preterm births are iatrogenic, associated with severe complications of pregnancy (e.g. hypertensive disorders, antepartum haemorrhage, infection), or the result of multiple pregnancies following assisted reproduction, a high proportion of preterm births occur following spontaneous preterm labour of unknown cause. Early intervention in this group of women would have a significant impact on neonatal mortality and morbidity figures. However, the endocrine changes preceding parturition in women remain elusive and this makes it difficult to predict spontaneous labour at term, let alone preterm labour. Moreover our understanding of myometrial physiology remains rudimentary, limiting our options to devise improved pharmacological strategies to control uterine contractility when this is indicated. There is a need for concerted European and international research efforts to improve our knowledge of the mechanism of labour in women, to identify diagnostic markers to predict preterm labour and to develop uterine selective drugs to inhibit uterine contractions in a safe and efficient manner. This aim will be achieved by multidisciplinary research efforts from academics and industry, using traditional laboratory and clinical research methods, as well as novel technologies.
The myometrium must remain relatively quiescent during pregnancy to accommodate growth and development of the feto-placental unit, and then must transform into a highly coordinated, strongly contracting organ at the time of labour for successful expulsion of the new born. The control of timing of labour is complex involving interactions between mother, fetus and the placenta. The timely onset of labour and delivery is an important determinant of perinatal outcome. Both preterm birth (delivery before 37 week of gestation) and post term pregnancy (pregnancy continuing beyond 42 weeks) are both associated with a significant increase in perinatal morbidity and mortality. There are multiple paracrine/autocrine events, fetal hormonal changes and overlapping maternal/fetal control mechanisms for the triggering of parturition in women. Our current article reviews the mechanisms for uterine distension and reduced contractions during pregnancy and the parturition cascade responsible for the timely and spontaneous onset of labour at term. It also discusses the mechanisms of preterm labour and post term pregnancy and the clinical implications thereof.
Endocrine; parturition; labour; term
Analyzing and monitoring uterine contractions during pregnancy is relevant to the field of reproductive health assessment. Its clinical importance is grounded in the need to reliably predict the onset of labor at term and pre-term. Preterm births can cause health problems or even be fatal for the fetus. Currently, there are no objective methods for consistently predicting the onset of labor based on sensing of the mechanical or electrophysiological aspects of uterine contractions. Therefore, modeling uterine contractions could help to better interpret such measurements and to develop more accurate methods for predicting labor. In this work, we develop a multiscale forward electromagnetic model of myometrial contractions during pregnancy. In particular, we introduce a model of myometrial current source densities and compute its magnetic field and action potential at the abdominal surface, using Maxwell’s equations and a four-compartment volume conductor geometry. To model the current source density at the myometrium we use a bidomain approach. We consider a modified version of the Fitzhugh-Nagumo (FHN) equation for modeling ionic currents in each myocyte, assuming a plateau-type transmembrane potential, and we incorporate the anisotropic nature of the uterus by designing conductivity-tensor fields.
We illustrate our modeling approach considering a spherical uterus and one pacemaker located in the fundus. We obtained a travelling transmembrane potential depolarizing from −56 mV to −16 mV and an average potential in the plateau area of −25 mV with a duration, before hyperpolarization, of 35 s, which is a good approximation with respect to the average recorded transmembrane potentials at term reported in the technical literature. Similarly, the percentage of myometrial cells contracting as a function of time had the same symmetric properties and duration as the intrauterine pressure waveforms of a pregnant human myometrium at term.
We introduced a multiscale modeling approach of uterine contractions which allows for incorporating electrophysiological and anatomical knowledge of the myometrium jointly. Our results are in good agreement with the values reported in the experimental technical literature, and these are potentially important as a tool for helping in the characterization of contractions and for predicting labor using magnetomyography (MMG) and electromyography (EMG).
Intra-uterine infection is a global problem and a significant contributor to morbidity and perinatal death. The host response to infection causes an inflammatory state that acts synergistically with microbial insult to induce preterm birth and fetal damage. Prompt and accurate diagnosis of intra-amniotic infection in the asymptomatic stage of the disease is critical for improved maternal and neonatal outcomes.
This article provides an overview of the most recent progress, challenges and opportunities for discovery and clinical implementation of various maternal serum, cervico-vaginal and amniotic fluid biomarkers in pregnancies complicated by intra-amniotic infection.
Clinically relevant biomarkers are critical to the accurate diagnostic of intra-uterine infection. Front end implementation of such biomarkers will also translate in lower incidence of early-onset neonatal sepsis which is an important determinant of neonatal morbidity and mortality associated with prematurity. However, of the hundreds of differentially expressed proteins, only few may have clinical utility and thus function as biomarkers. The small number of validation studies along with barriers to implementation of technological innovations in the clinical setting are current limitations.
Intra-uterine infection; Molecular microbiologic diagnostic tools; infection-induced inflammation; non-invasive diagnostics
Preterm birth (PTB) is one of the most important unsolved problems in reproductive medicine. This study aims to evaluate several maternal risk factors and outcome of pregnancies who were admitted for preterm spontaneous uterine contractions (PSUC).
From September 2007 to February 2009, 327 cases who were admitted for PSUC were retrospectively studied. They were classified according to their fetal numbers and presence of true versus threatened preterm labor (PTL).
There were 297 (90.82%) singleton, 27 (8.25%) twin and 3 (0.91%) triplet pregnancies. Only 12 women (3.6%) fulfilled the ACOG criteria for PTL who delivered in a few hours and 315 cases (96.3%) were classified as threatened PTL and most of them were discharged undelivered from the hospital. 103 cases were missed and 224 mothers and their 247 neonates remained. 121 women from this cohort had PTB and delivered before 259 days (54%). Pregnancy outcomes including; the time interval between admission for PSUC and delivery, the mean gestational ages at birth, birth weights, number and duration of NICU admissions were evaluated in each group.
Regular uterine contractions even in the absence of cervical changes should be considered as a potential risk factor for PTB. The most frequently associated maternal risk factors were history of abortion, infertility and previous PTB, and the most frequently associated complications were preterm rupture of membranes, vaginal bleeding and febrile diseases.
Preterm birth; Preterm uterine contraction; Preterm labor; Risk factor; Abortion; Infertility
Objective: To evaluate the outcome for all infants born before 33 weeks gestation until discharge from hospital.
Design: A prospective observational population based study.
Setting: Nine regions of France in 1997.
Patients: All births or late terminations of pregnancy for fetal or maternal reasons between 22 and 32 weeks gestation.
Main outcome measure: Life status: stillbirth, live birth, death in delivery room, death in intensive care, decision to limit intensive care, survival to discharge.
Results: A total of 722 late terminations, 772 stillbirths, and 2901 live births were recorded. The incidence of very preterm births was 1.3 per 100 live births and stillbirths. The survival rate for births between 22 and 32 weeks was 67% of all births (including stillbirths), 85% of live births, and 89% of infants admitted to neonatal intensive care units. Survival increased with gestational age: 31% of all infants born alive at 24 weeks survived to discharge, 78% at 28 weeks, and 97% at 32 weeks. Survival among live births was lower for small for gestational age infants, multiple births, and boys. Overall, 50% of deaths after birth followed decisions to withhold or withdraw intensive care: 66% of deaths in the delivery room, decreasing with increasing gestational age; 44% of deaths in the neonatal intensive care unit, with little variation with gestational age.
Conclusion: Among very preterm babies, chances of survival varies greatly according to the length of gestation. At all gestational ages, a large proportion of deaths are associated with a decision to limit intensive care.
Lack of data is a critical barrier to addressing the problem of stillbirth in countries with the highest stillbirth burden. Our study objective was to estimate the levels, types, and causes of stillbirth in rural Sylhet district of Bangladesh.
A complete pregnancy history was taken from all women (n = 39 998) who had pregnancy outcomes during 2003-2005 in the study area. Verbal autopsy data were obtained for all identified stillbirths during the period. We used pre-defined case definitions and computer programs to assign causes of stillbirth for selected causes containing specific signs and symptoms. Both non-hierarchical and hierarchical approaches were used to assign causes of stillbirths.
A total of 1748 stillbirths were recorded during 2003-2005 from 48,192 births (stillbirth rate: 36.3 per 1000 total births). About 60% and 40% of stillbirths were categorized as antepartum and intrapartum, respectively. Maternal conditions, including infections, hypertensive disorders, and anemia, contributed to about 29% of total antepartum stillbirths. About 50% of intrapartum stillbirths were attributed to obstetric complications. Maternal infections and hypertensive disorders contributed to another 11% of stillbirths. A cause could not be assigned in nearly half (49%) of stillbirths.
The stillbirth rate is high in rural Bangladesh. Based on algorithmic approaches using verbal autopsy data, a substantial portion of stillbirths is attributable to maternal conditions and obstetric complications. Programs need to deliver community-level interventions to prevent and manage maternal complications, and to develop strategies to improve access to emergency obstetric care. Improvements in care to avert stillbirth can be accomplished in the context of existing maternal and child health programs. Methodological improvements in the measurement of stillbirths, especially causes of stillbirths, are also needed to better define the burden of stillbirths in low-resource settings.
A detailed retrospective analysis was made of the records of 486 preterm infants, who accounted for 5-1% of all births during 1973 and 1974. Whereas preterm delivery did not contribute to perinatal mortality in terms of stillbirth, it outweighed all other causes in terms of early neonatal deaths. Preterm birth was responsible for 85% of the early neonatal deaths not due to lethal congenital deformities. Early neonatal mortality rates were closely linked both to gestational age and birth weight and to the reason for preterm birth. Early neonatal mortality was high (97 per 1000) when preterm labour was spontaneous, whether or not associated with material or fetal disease or with multiple pregnancy, but low (27 per 1000) when preterm delivery was elective. Preventing spontaneous preterm labour would considerably reduce neonatal mortality in our community.