Marijuana use in young mothers and adverse pregnancy outcomes: a retrospective cohort study

Abstract

Objective To evaluate the association between marijuana use and a composite adverse pregnancy outcome using biological sampling. Design Retrospective cohort study. Setting Single tertiary center. Population Young women (13–22 years old) with singleton, non‐anomalous pregnancies delivered from September 2011 to May 2017. Methods Exposure was defined as marijuana detected on universal urine toxicology testing or by self‐report. Multivariable logistic regression modelling was used to estimate the effect of any marijuana use on the primary composite outcome. The effect of marijuana exposure was also estimated for self‐reported use, toxicology‐detected use, and multiple use detected by toxicology. Main outcome measure The primary composite outcome included spontaneous preterm birth, hypertensive disorders of pregnancy, stillbirth, or small for gestational age. Results Of 1206 pregnant young women, 17.5% (n = 211) used marijuana. Among the women who used marijuana, 8.5% (n = 18) were identified by self‐report alone, 63% (n = 133) by urine toxicology alone, and 28.4% (n = 60) by both. Urine toxicology testing results were available for 1092 (90.5%) births. The composite outcome occurred more frequently in pregnancies exposed to marijuana (46 versus 34%, P < 0.001). This remained significant after adjusting for race/ethnicity and tobacco in the multivariable model (adjusted OR 1.50, 95% CI 1.09–2.05). When marijuana exposure was defined by self‐report only, the association with adverse pregnancy outcome became non‐significant (adjusted OR 1.01, 95% CI 0.62–1.64). Conclusion In a population of young women with nearly universal biological sampling, marijuana exposure was associated with adverse pregnancy outcomes. The heterogeneity of findings in existing studies evaluating the impact of marijuana on mothers and neonates may result from the incomplete ascertainment of exposure. Tweetable abstract Marijuana use, as detected by universal urine testing, was associated with a composite adverse pregnancy outcome among young mothers.

Teenage pregnancy

“…33 Screening for other drugs is also important, with data from the USA suggesting that a sixth of younger pregnant women use marijuana in pregnancy, with a significant association between drug use and a composite outcome of spontaneous preterm birth, hypertensive disorders of pregnancy, stillbirth or small size for gestational age. 34 Recognition of the use of these drugs requires enquiry about them. GPs are well placed to develop a trusting relationship that allows regular discussion about drug use with teenagers.…”

Update on the developmental consequences of cannabis use during pregnancy and lactation

“…Studies using model species such as monkeys, rats and mice provide the opportunity to control many of the environmental factors that impact study outcomes in human research. Results from investigations of prenatal cannabis exposure with animal models lend support to the general themes that can be extracted from the human literature, particularly No robust effect on early mental development (Astley & Little, 1990;Fried & Watkinson, 1988;Richardson et al, 1995) Some evidence of alterations in fetal growth, particularly SGA infants (El Marroun et al, 2009;Saurel-Cubizolles et al, 2014;Rodriguez et al, 2019;Warshak et al, 2015) Disturbance in sleep cycling (Scher et al, 1988) Increased aggression and attentional problems in females (El Marroun et al, 2011) Early and mid-childhood (3-11 years)…”

“…Results indicated a 70% increase in risk of small-forgestational age (SGA) infants in women who used cannabis during pregnancy. An elevated risk of SGA infants has been found in other studies using THC urine assays to confirm exposure (Rodriguez et al, 2019;Warshak et al, 2015) and in studies relying on maternal self-report (Corsi, Walsh, Weiss et al, 2019;Luke, Hutcheon, & Kendall, 2019;Saurel-Cubizolles, Prunet, & Blondel, 2014). The association between maternal cannabis use during pregnancy and SGA infants remained significant in a study where women cousing tobacco were excluded from the analysis (El Marroun et al, 2009).…”

“…Because many women do not provide reliable estimates of cannabis use, misclassification of exposure can lead to biased results. This has been clearly demonstrated in studies where the adverse impact of prenatal cannabis exposure was only revealed after statistical analyses were restricted to women with positive THC urine toxicology results (Rodriguez et al, 2019;Zuckerman, Amaro, & Cabral, 1989). Additionally, the possible influence of covariates such as carbon monoxide exposure from smoking cannabis must be considered when interpreting study results.…”

“…When compared to unexposed controls, prenatallyexposed infants may also be at an increased risk for prematurity and reduced birthweight (Baer et al, 2019;Corsi, Walsh, Weiss et al, 2019;Howard, Dhanraj, Devaiah, & Lambers, 2019;Luke et al, 2019;Petrangelo, Czuzoj-Shulman, Balayla, & Abenhaim, 2019;Rodriguez et al, 2019). Despite research findings that suggest prenatal exposure is associated with changes in early growth trajectories, there is no robust evidence of an enduring negative effect.…”