Using data collected as a follow-up to a randomized trial, Melissa Gladstone and colleagues show that during the first two years of life, infants born preterm in southern Malawi are disadvantaged in terms of mortality, growth, and development.
Preterm birth is considered to be associated with an estimated 27% of neonatal deaths, the majority in resource-poor countries where rates of prematurity are high. There is no information on medium term outcomes after accurately determined preterm birth in such settings.
Methods and Findings
This community-based stratified cohort study conducted between May–December 2006 in Southern Malawi followed up 840 post-neonatal infants born to mothers who had received antenatal antibiotic prophylaxis/placebo in an attempt to reduce rates of preterm birth (APPLe trial ISRCTN84023116). Gestational age at delivery was based on ultrasound measurement of fetal bi-parietal diameter in early-mid pregnancy. 247 infants born before 37 wk gestation and 593 term infants were assessed at 12, 18, or 24 months. We assessed survival (death), morbidity (reported by carer, admissions, out-patient attendance), growth (weight and height), and development (Ten Question Questionnaire [TQQ] and Malawi Developmental Assessment Tool [MDAT]). Preterm infants were at significantly greater risk of death (hazard ratio 1.79, 95% CI 1.09–2.95). Surviving preterm infants were more likely to be underweight (weight-for-age z score; p<0.001) or wasted (weight-for-length z score; p<0.01) with no effect of gestational age at delivery. Preterm infants more often screened positively for disability on the Ten Question Questionnaire (p = 0.002). They also had higher rates of developmental delay on the MDAT at 18 months (p = 0.009), with gestational age at delivery (p = 0.01) increasing this likelihood. Morbidity—visits to a health centre (93%) and admissions to hospital (22%)—was similar for both groups.
During the first 2 years of life, infants who are born preterm in resource poor countries, continue to be at a disadvantage in terms of mortality, growth, and development. In addition to interventions in the immediate neonatal period, a refocus on early childhood is needed to improve outcomes for infants born preterm in low-income settings.
Please see later in the article for the Editors' Summary
Being born at term in Africa is not necessarily straightforward. In Malawi, 33 of every 1,000 infants born die in the first 28 days after birth; the lifetime risk for a mother dying during or shortly after pregnancy is one in 36. The comparable figures for the United Kingdom are three infants dying per 1,000 births and a lifetime risk of maternal death of one in 4,700. But for a baby, being born preterm is even more risky and the gap between low- and high-income countries widens still further. According to a World Health Organization report in 2010, a baby born at 32 weeks of gestation (weighing around 2,000 g) in Africa has little chance of survival, while the chances of survival for a baby born at 32 weeks in North America or Europe are similar to one born at term. There are very few data on the longer term outcomes of babies born preterm in Africa and there are multiple challenges involved in gathering such information. As prenatal ultrasound is not routinely available, gestational age is often uncertain. There may be little routine follow-up of preterm babies as is commonplace in high-income countries. Data are needed from recent years that take into account both improvements in perinatal care and adverse factors such as a rising number of infants becoming HIV positive around the time of birth.
Why Was This Study Done?
We could improve outcomes for babies born preterm in sub-Saharan Africa if we understood more about what happens to them after birth. We cannot assume that the progress of these babies will be the same as those born preterm in a high-income country, as the latter group will have received different care, both before and after birth. If we can document the problems that these preterm babies face in a low-income setting, we can consider why they happen and what treatments can be realistically tested in this setting. It is also helpful to establish baseline data so that changes over time can be recorded.
The aim of this study was to document four specific outcomes up to the age of two years, on which there were few data previously from rural sub-Saharan Africa: how many babies survived, visits to a health center and admissions to the hospital, growth, and developmental delay.
What Did the Researchers Do and Find?
The researchers examined a group of babies that had been born to mothers who had taken part in a randomized controlled trial of an antibiotic to prevent preterm birth. The trial had previously shown that the antibiotic (azithromycin) had no effect on how many babies were born preterm or on other measures of the infants' wellbeing, and so the researchers followed up babies from both arms of the trial to look at longer term outcomes. From the original group of 2,297 women who took part in the trial, they compared 247 infants born preterm against 593 term infants randomly chosen as controls, assessed at 12, 18, or 24 months. The majority of the preterm babies who survived past a month of age (all but ten) were born after 32 weeks of gestation. Compared to the babies born at term, the infants born preterm were nearly twice as likely to die subsequently in the next two years, were more likely to be underweight (a third were moderately underweight), and to have higher rates of developmental delay. The commonest causes of death were gastroenteritis, respiratory problems, and malaria. Visits to a health center and admissions to hospital were similar in both groups.
What Do these Findings Mean?
This study documents longer term outcomes of babies born preterm in sub-Saharan Africa in detail for the first time. The strengths of the study include prenatal ultrasound dating and correct adjustment of follow-up age (which takes into account being born before term). Because the researchers defined morbidity using routine health center attendances and self-report of illnesses by parents, this outcome does not seem to have been as useful as the others in differentiating between the preterm and term babies. Better means of measuring morbidity are needed in this setting.
In the developed world, there is considerable investment being made to improve care during pregnancy and in the neonatal period. This investment in care may help by predicting which mothers are more likely to give birth early and preventing preterm birth through drug or other treatments. It is to be hoped that some of the benefit will be transferable to low-income countries. A baby born at 26 weeks' gestation and admitted to a neonatal unit in the United Kingdom has a 67% chance of survival; preterm babies born in sub-Saharan Africa face a starkly contrasting future.
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001121.
UNICEF presents useful statistics on mother and child outcomes
The World Health Organization has attempted to analyse preterm birth rates worldwide, including mapping the regional distribution and has also produced practical guides on strategies such as Kangaroo Mother Care, which can be used for the care of preterm infants in low resource settings
Healthy Newborn Network has good information on initiatives taking place to improve neonatal outcomes in low income settings
The March of Dimes, a nonprofit organization for pregnancy and baby health, provides information on research being conducted into preterm birth
Tommy's is a nonprofit organization that funds research and provides information on the risks and causes of premature birth