Maternal Marijuana Use, Adverse Pregnancy Outcomes and Neonatal Morbidity

Torri D. Metz,  Ms Amanda A. Allshouse, Carol J. Rowland Hogue, Robert L. Goldenberg, Donald J. Dudley, Michael W. Varner, Deborah L. Conway,  George R. Saade,  and Robert M. Silver

American Journal of Obstetrics and Gynecology, 2017 October ; 217, (4), 478.e1–478.e8.

doi :10.1016/j.ajog.2017.05.050

 

Abstract

Background—The NICHD Stillbirth Collaborative Research Network (SCRN) previously demonstrated an association between stillbirth and maternal marijuana use as defined by the presence of 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid (THC) in the umbilical cord homogenate. However, the relationship between marijuana use and perinatal complications in live births is uncertain.

Objective—Our aim was to examine if maternal marijuana use is associated with increased odds of adverse pregnancy outcomes and neonatal morbidity among liveborn controls in the SCRN cohort.

Study Design—Secondary analysis of singleton, liveborn controls in the SCRN dataset. Marijuana use was measured by self-report and/or the presence of THC in umbilical cord homogenate. Tobacco use was measured by self-report and/or presence of any cotinine in maternal serum. Adverse pregnancy outcome was a composite of small for gestational age (SGA), spontaneous preterm birth resulting from preterm labor with or without intact membranes (SPTB), and hypertensive disorders of pregnancy (HTN). Neonatal morbidity included neonatal intensive care unit (NICU) admission and composite neonatal morbidity (pulmonary morbidity, necrotizing enterocolitis, seizures, retinopathy of prematurity, infection morbidity, anemia requiring blood transfusion, neonatal surgery, hyperbilirubinemia, neurological morbidity or death prior to hospital discharge). Effect of maternal marijuana use on the probability of an adverse outcome was estimated using weighted methodology to account for over-sampling in the original study. THC cord homogenate analysis was performed in the subset of women for whom biospecimens were available. Comparisons using logistic modeling, chi-square, and t-tests were weighted to account for oversampling of preterm births and non-Hispanic blacks. Results are reported as weighted percent and unweighted frequencies.

Results—Maternal marijuana use was identified in 2.7% (unweighted frequency 48/1610) of live births. Use was self-reported by 1.6% (34/1610) and detected by THC in cord homogenate for 1.9% (17/897), n=3 overlapping. Rate of tobacco use was 12.9% (217/1610), with 10.7% (167/1607) by self-report and 9.5% (141/1313) by serum cotinine. The composite adverse pregnancy outcome was not significantly increased in women with marijuana use compared to non-users (31.2% versus 21.2%, p=0.14). After adjustment for tobacco, clinical and socioeconomic factors, marijuana use was not associated with the composite adverse pregnancy outcome (aOR 1.29, 95% CI 0.56–2.96). Similarly, among women with umbilical cord homogenate and serum cotinine data (n=765), marijuana use was not associated with adverse pregnancy outcomes (aOR 1.02, 95% CI 0.18– 5.66).

NICU admission rates were not statistically different between groups (16.9% users versus 9.5% non-users, p=0.12). Composite neonatal morbidity or death was more frequent among neonates of mothers with marijuana use compared to non-users (14.1% versus 4.5%, p=0.002). In univariate comparisons, the components of the composite outcome that were more frequent in neonates of marijuana users were infection morbidity (9.8% versus 2.4%, p<0.001), and neurologic morbidity (1.4% versus 0.3%, p=0.002). After adjustment for tobacco, race and other illicit drug use, marijuana use was still associated with composite neonatal morbidity or death (aOR 3.11, 95% CI 1.40–6.91).

Conclusion—Maternal marijuana use was not associated with a composite of SGA, SPTB, or HTN. However, it was associated with an increased risk of neonatal morbidity.

Keywords : adverse pregnancy outcome; biological sampling; maternal marijuana use; THC; umbilical cord homogenate

Introduction

Legalization of marijuana in the United States has resulted in a resurgence of interest in its health effects. More women now report using marijuana either recreationally or to treat nausea and vomiting of pregnancy.1 Between 2002 and 2014, past-month use among pregnant women increased from 2.4% to 3.9%.2 With increasing use, there is an urgent need for high quality data regarding the health effects of marijuana in pregnancy in order to appropriately educate women and healthcare providers. Previous studies on the association between marijuana use and perinatal outcomes have yielded mixed results,3–8 likely due to incomplete ascertainment of exposure without quantification of marijuana use, and without corroboration of use with biological sampling.3 The Eunice Kennedy Shriver National Institute of Child Health and Human Development Stillbirth Collaborative Research Network (SCRN) recently demonstrated an association between maternal marijuana use and stillbirth.9 The SCRN utilized umbilical cord homogenate assays, allowing for detection of use from the second trimester onward. Our objective was to examine if maternal marijuana use is associated with increased odds of adverse pregnancy outcomes (small for gestational age (SGA), spontaneous preterm birth (SPTB), and hypertensive disorders of pregnancy (HTN)) and neonatal morbidity (neonatal intensive care unit (NICU) admission, composite neonatal morbidity and/or death) among liveborn controls in the SCRN cohort.

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