SUMMARY: DOES MARIJUANA AFFECT FERTILITY IN WOMEN
According to this study marijuana negatively affects a woman’s fertility, decreasing the probability of becoming pregnant by 41% per menstrual cycle, with abnormal luteinizing hormone and testosterone levels, and increase in the number of anovulatory cycles.
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In the last 20 years self-reported use of cannabis, also known as marijuana, weed or pot, has nearly doubled among women of reproductive age. This increase in use has also been reported in women just prior to and during pregnancy.
Despite this normalization and acceptance of cannabis use among the community, evidence to oppose or support its use before and during pregnancy is scarce.
Studies suggest cannabinoids can potentially block GnRH (Gonadotropin-releasing hormone) essential for ovulation, endometrial receptivity and embryo implantation although related studies on fecundability and pregnancy loss reported no statistically significant effects.
This interesting finding however may be the result of self-reported cannabis use in these studies instead of more accurate laboratory measurement.
To examine associations between cannabis use during pregnancy establishment, with fecundability, live birth and pregnancy loss, by measuring urinary metabolites at multiple time points.
Women aged 18 to 40 years old, trying to conceive, with 1 or 2 prior pregnancy losses participating in the EAGeR (Effects of Aspirin in Gestation and Reproduction) trial were assessed for eligibility.
After excluding for alcohol or illicit drug use, psychiatric disorders and infertility diagnosis, a total of 1228 women trial results were analysed.
All women were followed for up to 6 menstrual cycles while trying to conceive, and throughout pregnancy for those who successfully fell pregnant.
Use of cannabis was assessed both via a questionnaire and laboratory analysis of metabolites from urinary samples, provided preconception and during early pregnancy.
Final study outcomes included time to hCG detected pregnancy, rate of live birth and pregnancy loss, along with hormone concentrations and anovulation.
Initial analysis of cannabis use revealed 62 out of 1228 women used cannabis during the preconception period, and only 11 out of 789 women who fell pregnant used cannabis during the first 8 weeks of pregnancy.
Baseline characteristics of participants found cannabis use was linked to more frequent alcohol and antidepressant use, as well as more frequent intercourse.
Analysis of outcomes showed the rate of pregnancy was significantly less among women who used cannabis during preconception (44% vs 66%).
Overall fecundability for women using cannabis was reduced by 41%, in both unadjusted and adjusted models. Similarly, the probability of live birth, before adjustment, was also lower (42% vs 55%), although the number of live births among cannabis users was too small to interpret with confidence.
Interestingly pregnancy loss among preconception cannabis users was not significantly higher (27% vs 24%). On the other hand, due to the small number of women using cannabis in the first 8 weeks of pregnancy, no further conclusions could be made.
Hormone analysis showed that both LH and LH:FSH ratios was significantly higher among cannabis users, with a moderate increase in testosterone levels.
|Total testosterone (ng/dL)||23.5||20.2||0.06|
|Free testosterone (nmol/L)||0.34||0.27||0.06|
The risk of anovulation was also increased in cannabis users, 19% vs 9%, although the number of anovulatory cannabis users was too small to confirm statistical significance (P=0.09).
Finally advanced (sensitivity) analysis, using both a simulation study and e-value method, to test the potential effect of cannabis use by male partners on the results, confirmed the likelihood of these findings being false, to be highly unlikely.
- Small sample number for positive users.
- No data on cannabis use in male partners.
This study was supported by the Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health
Naturally occurring compounds found in the Cannabis sativa plant.
The probability of conception in a single menstrual cycle.
An intermediate or end product of metabolism.
The probability that a result occurred by random chance.
Wise L A, et al (2018). Marijuana use and fecundability in a North American preconception cohort study. https://doi.org/10.1136/jech-2017-209755
Kasman A M, et al. (2018). Association between use of marijuana and time to pregnancy in men and women: findings from the National Survey of Family Growth. https://doi.org/10.1016/j.fertnstert.2018.01.015
Joesoef M R, et al. (1993). Fertility and use of cigarettes, alcohol, marijuana, and cocaine. https://doi.org/10.1016/1047-2797(93)90080-n
Mueller B A, et al. (1990). Recreational drug use and the risk of primary infertility. https://doi.org/10.1097/00001648-199005000-00003
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