Maternal opioid analgesic use during pregnancy and adverse birth outcomes

• In Event: 3-004 - Studying the Prenatal and Neonatal Environments and their Effects on Development Using Secondary data

Abstract

A general increase in morbidity and mortality associated with prescription opioid analgesic (POA) use has generated widespread public health concerns (Kolodny et al., 2015). Notably, POA use among pregnant women is increasing (Desai et. al, 2014) and is associated with adverse birth outcomes (Yazdy et. al., 2015). However, it remains unclear whether these associations are attributable to causal effects or other risk factors associated with maternal POA use during pregnancy. Because pregnant women are typically excluded from randomized clinical trials of medications, researchers must use observational methods with design features that help account for confounding factors to evaluate potential consequences of prenatal POA exposure. Thus, in this study, we used methods to account for both measured and unmeasured confounding factors to evaluate associations between maternal-reported first-trimester POA use and two birth outcomes -- preterm birth (PTB; <37 gestational weeks) and small for gestation age (SGA; birth weight <2 SDs below the expected weight for gestational age).

We studied 1,729,005 singleton live births recorded in the Swedish Medical Birth Registry between 1996 and 2013. We linked several Swedish registers to obtain information on biological relationships, birth outcomes, diagnoses from hospital admissions and specialist outpatient care, criminal convictions, and education level. Of the 8,025 (0.5%) exposed offspring, 7.6% were PTB and 2.5% were SGA. Of the unexposed offspring, 6.3% were PTB and 1.9% were SGA.

We first assessed population-wide associations between first-trimester POA exposure and the birth outcomes while controlling for numerous measured parental and pregnancy characteristics. Then, we compared risk of the outcomes among differentially exposed siblings while adjusting for measured characteristics that may vary among siblings. By design, sibling comparisons account for all unmeasured factors that make sibling similar, including influences from maternal conditions that are stable across pregnancies.

Population models indicated that first-trimester POA exposure was associated with PTB (odds ratio [OR]=1.56, 95% CI: 1.44-1.70) and SGA (OR=1.24, 95% CI: 1.09-1.41), and these associations were robust in sibling comparison models (PTB OR=1.39, 95% CI: 1.18-1.64; SGA OR=1.44, 95% CI: 1.08-1.91). Our results are consistent with the possibility that first-trimester prenatal POA exposure may result in an increased risk of birth problems. However, more research is needed to test alternative explanations for the associations. In particular, research needs to test for confounding by factors that vary across a woman’s pregnancies.

Authors

• Ayesha Sujan, Indiana University, Bloomington
  Presenting Author

• Patrick Quinn, Indiana University

• Martin Rickert, Indiana University

• Kelsey Wiggs, Indiana University

• Paul Lichtenstein, Karolinska Institute

• Henrik Larsson, Örebro University

• Sara Oberg, Karolinska Institute

• Brian D'Onofrio, Indiana University