Maternal Marijuana Exposure, Feto-Placental Weight Ratio and Placental Histology

• Type of Material: Article
• Authors: Torri D. Metz, University of Utah; Amanda A. Allshouse, University of Utah; Halit Pinar, Brown University; Michael Varner, University of Utah; Marcela C. Smid, University of Utah; Carol J Hogue, Emory University; Donald J. Dudley, University of Virginia; Radek Bukowski, University of Texas at Austin; George R. Saade, University of Texas at Galveston; Robert L. Goldenberg, Columbia University; Uma Reddy, Yale University; Robert M. Silver, University of Utah
• Language: English
• Date: 2020-09-24
• Publisher: Georg Thieme Verlag KG
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2020 The Author(s). Rights managed by Thieme.
• Final Published Version (URL): https://doi.org/10.1055%2Fs-0040-1717092
• Title of Journal or Parent Work: American Journal of Perinatology
• Volume: 39
• Issue: 5
• Start Page: 546
• End Page: 553
• Grant/Funding Information: Dr. Metz was supported by the National Institute on Child Health and Human Development (NICHD) under award number 5K12HD001271 during the completion of this work. Dr. Smid was supported by the National Institute on Child Health and Human Development (NICHD) under award number 1K12HD085816 during the completion of this work.
• Keywords: placenta; stillbirth; marijuana; feto-placental ratio
• Research Categories: Health Sciences, Obstetrics and Gynecology

Abstract

Objective: Marijuana use is associated with placenta-mediated adverse pregnancy outcomes including fetal growth restriction, but the mechanism remains uncertain. The objective was to evaluate the association between maternal marijuana use and the feto-placental weight ratio (FPR). Secondarily, we aimed to compare placental histology of women who used marijuana to those who did not. Study Design: This was a secondary analysis of singleton pregnancies enrolled in a multicenter, case-control stillbirth study. Prior marijuana use was detected by electronic medical record abstraction or cord homogenate positive for 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid. Prior tobacco use was detected by self-report or presence of maternal serum cotinine. Stillbirths and live births were considered separately. The primary outcome was FPR. Association of marijuana use with FPR was estimated with multivariable linear modeling adjusted for fetal sex, preterm birth and tobacco use. Comparisons between groups for placental histology were made using chi-square and stratified by live birth and stillbirth, term and preterm deliveries, and fetal sex. Results: Of 1027 participants, 224 were stillbirths and 803 were live births. Overall 41 (4%) women used marijuana during the pregnancy. The FPR ratio was lower among exposed offspring but reached statistical significance only for term stillbirths (mean 6.84 with marijuana use versus mean 7.8 without use, P<0.001). In multivariable modeling, marijuana use was not significantly associated with FPR (P=0.09). There were no differences in histologic placental features among those with and without marijuana use overall nor in stratified analyses. Conclusion: Exposure to marijuana may not be associated with FPR. Similarly, there were no placental histologic features associated with marijuana exposure. Further study of the influence of maternal marijuana use on placental development and function is warranted to better understand the association between prenatal marijuana use and poor fetal growth.