Prior to the Vessels Intervention that was introduced in the Early Start Plus group, there was no standardized way of assessing for actual quantity and frequency patterns of alcohol use by Early Start patients. In addition, if a patient continued to drink alcohol in pregnancy and did not want to quit but could agree to cut down her drinking, Early Start Specialists had no tools available to assist them with conversations aimed not at abstinence but at harm reduction. As Early Start is an abstinence based program, it was awkward for the Specialists to enter into harm-reduction conversations without feeling like they were somehow “giving permission” to the women to drink. The Vessels Intervention provided a comfortable tool for successfully navigating these difficult conversations. This is probably the most significant contribution of the intervention.
Although the intervention did not result in significantly lower rates of neonatal and maternal outcomes when comparing the two types of interventions, in several cases the analyses suggested that the women in the Early Start Plus group had more favorable outcomes than the women in the Early Start group. For example, the Early Start Plus group had a lower unadjusted rate of preterm labor than the Early Start group and the controls, and significantly lower odds of preterm labor than the controls. This finding is highly relevant. About 9% of pregnant women in KPNC are hospitalized for preterm labor. Given that there are about 30,000 deliveries per year in this region, any reduction in this rate would have a positive effect on the pregnant population and have the additional benefit of lower costs. A related outcome is preterm delivery, where we found in the unadjusted analyses that women in Early Start Plus had about one-third the rate of preterm delivery of those in Early Start (0.4 vs. 1.1 respectively). Preterm babies have increased morbidity and mortality as well as costs of care, so any reduction in this rate is beneficial. Taken together, these results suggest that Early Start Plus appears to be helpful in reducing the incidence of preterm events. Future research with the Vessels Intervention will attempt to understand the mechanism(s) through which this might be occurring.
Another important finding was the significantly lower odds of low birth weight infants in the Early Start group compared to the controls. While this does not inform our trial comparing Early Start Plus to Early Start, this result highlights the inherent value of high-intensity interventions placed in prenatal clinics which are targeted towards high risk women. Low birth weight infants are usually also preterm and have increased morbidity, mortality and costs of care (Little 1977
The nearly identical high NICU admission rates for the 3 study groups were not surprising. Many NICU admissions are for highly discretionary reasons, such as “rule out sepsis”, and babies of women who are identified as substance users during pregnancy are often admitted for observation, even if there is documentation that the mother is no longer using.
There are a number of important limitations to our study. The first concerns the comparability of the study groups on demographics and risk factors. In general, the control group had a better demographic profile in terms of characteristics that put women at risk (such as low income, higher age) and traditional risk factors (such as smoking before or during pregnancy). Nevertheless, the control group had generally worse baby and maternal outcomes than the two Early Start groups, which emerged as significant for two outcomes (low birth weight and preterm labor) in the multivariate analyses. This pattern of results highlights the value of both the Early Start and the Early Start Plus interventions, since women treated in those groups would otherwise have been thought to have had worse, not better, outcomes than those in the control group.
A second limitation stems from the smaller than anticipated sample size, which was due to difficulties with recruitment in this multi-site trial. We based our original power estimations on the comparison of rates of a combined maternal and neonatal outcome measure. This variable had a positive value if the mother-infant pair had any of the neonatal and maternal outcomes considered and was negative if they had none. We estimated that the Early Start Plus rate would be 12%, Early Start would be 14-16% and the controls would be 18%. To achieve 80% power with a 2-sided test and alpha = 0.05, we needed 555 women in each group to detect the difference between a control group rate of 18% and an Early Start Plus rate of 12%. We noted in our proposal that we would not have sufficient power to detect differences between Early Start Plus and Early Start but expected the rate for Early Start Plus to be lower than the rate for Early Start and that any reduction in the rate would have a public health impact. The results of the study were: Early Start Plus rate = 14.3% (n=251), Early Start rate = 14.9% (n=275), and control rate = 19.5% (n=318). The final sample sizes were about half of what was anticipated, but the rates in the ESP and control groups were higher than predicted. Given the sample size we achieved, we had 30% power to detect significance of the difference we found at the 0.05 level. Thus our power was limited, compromising our ability to detect significant results.
We had hypothesized better maternal and infant outcomes for Early Start Plus compared to Early Start, but found no differences in the multivariate analyses. However, several other recent, well-designed alcohol trials have similarly failed to detect differences between study groups. For example, Project MATCH found similar drinking outcomes for motivation enhancement therapy, cognitive behavioral therapy, and 12-step facilitation (Project MATCH Research Group, 1996
); trials comparing medical and social model treatment did not find different abstinence rates for patients treated in day hospital or community residential treatment (Witbrodt et al., 2007b
), nor for those randomized to clinical vs. social model day treatment (Kaskutas, Witbrodt, & French, 2004
). Also see McKay, Alterman, McLellan, Snider, & O'Brien (1995)
for similar results with male-only samples.
We believe this trend across studies reflects the very high quality of treatment delivery, regardless of modality, as well as common therapeutic ingredients that are present in seemingly diverse treatment approaches (NIAAA, 2006
). Certainly that is the case here. Early Start is an intensive abstinence-based, patient-focused prenatal program in which highly skilled therapists provide compassionate support throughout pregnancy. In a recent study (Goler, Armstrong, Taillac & Osejo, 2008
), substance abusing women treated by the Early Start Program were found to have significantly better neonatal and maternal outcomes than untreated substance abusing women. Perhaps it is not surprising that the Early Start Plus Group did not do significantly better than the Early Start Group; it was being compared to an already very high standard of care.
A key contribution of Early Start Plus is that its computerized assessment of drink sizes provided a guided framework in which the same high caliber of therapists (the Early Start Specialists) could discuss drinking during pregnancy without feeling they were giving women permission to drink. We had hoped to be able to compare drinking outcomes between the Early Start Plus and the Early Start groups, to measure the effectiveness of Early Start Plus in reducing heavy drinking and to determine whether it also resulted in less abstention than Early Start (which was abstention-focused and did not encourage discussions about how to drink less). Toward that end, telephone interviews near the end of pregnancy were planned to provide the trial with drinking measures that would have allowed us to study changes that occurred in drinking following the Early Start Plus and the Early Start interventions. However, only about half the women in the Early Start Plus group completed a follow-up interview (compared to over 90% in the Early Start and the control groups), thus leaving a very small sample size for studying drinking among women who received Early Start Plus. Another limitation with the follow-up interviews among women in Early Start Plus arises from their heightened awareness of standard drink sizes; the follow-up interviews asked women about their drinking in terms of standard drinks, thus introducing still another bias to the drinking data of women in the Early Start Plus group.
One final point about Early Start Plus is how well received it was by the Early Start Specialists and clients alike. The Specialists felt that the intervention was a useful tool in their assessments of drinking during pregnancy, and that it was indispensable for women who were resistant to abstinence. Perhaps the most valuable use of the computerized program and actual vessels models is as an assessment tool for substance abuse treatment providers, including licensed clinical social workers, which genuinely facilitates an in-depth discussion with pregnant women about their drinking. We hope to study this in subsequent research, and to increase the reliability and validity of drinking assessments in prenatal clinics using the computerized tool and the models of drinking vessels. The computerized intervention is available from the authors upon request.