In a recent U.S. National Institutes of Health (NIH) study of 1,200 women aged 18 to 40 who were trying to become pregnant, marijuana use was connected to a 40 percent decreased chance of conception. Titled “Cannabis Use While Trying to Conceive: a Prospective Cohort Study Evaluating Associations With Fecundability, Live Birth and Pregnancy Loss” and published January 11, 2021, in the journal Human Reproduction, the study’s results suggest that women who are attempting to have a child will have a better chance at pregnancy if they refrain from cannabis use while making that effort. How Worried Should Cannabis-Using Prospective Mothers Be? Having children is or will be a primary life goal for many women and couples who use cannabis. Women who use cannabis should be aware that marijuana use might be interfering in that goal. The American College of Obstetricians and Gynecologists’ Committee on Obstetric Practice recommends discouraging obstetrician–gynecologists from suggesting medical cannabis therapeutics during preconception, pregnancy, and lactation. The Committee on Obstetric Practice believes, with limited evidence, that prospective mothers should stop medical cannabis use and adopt an alternative therapy for which the pregnancy risks are better known. Any potential interfering aspects of marijuana with human fertility should be considerations for cannabis using women attempting to become pregnant, and also for any men partnering with cannabis using prospective mothers. However, the “Cannabis Use While Trying to Conceive” study did uncover one consolation to using cannabis while attempting to become pregnant: Despite a lower rate of fecundability, aspiring mothers who used cannabis were found to report an increased frequency of intercourse. Despite reduced incidence of conception among women who use marijuana while attempting to become pregnant, marijuana use should in no way be considered a contraceptive strategy. When the six month “Cannabis Use While Trying to Conceive” study concluded, 42 percent of the marijuana using women attempting to become pregnant were in fact pregnant. The 42 percent pregnancy rate among cannabis using women seems like a solid marker of success, until contrasted with the 66 percent of marijuana abstinent women who became pregnant during the study. Put simply, marijuana use may reduce your chance of getting pregnant but it does not eliminate it. Women who use marijuana and have sex intending to become pregnant should understand that the marijuana and pregnancy study results, though perhaps cause for caution, are far from conclusive proof that marijuana use inhibits conception. What were the study’s concrete findings? The only physical discrepancy the study’s scientists found between cannabis using prospective mothers and prospective mothers who remained marijuana abstinent is a difference in reproductive hormones connected with ovulation. Prospective mothers who used cannabis were found to have higher overall levels of luteinizing hormone. The cannabis users’ proportions of luteinizing hormone to follicle stimulating hormone were also higher. Produced in the pituitary gland, a sharp rise in luteinizing hormone during a woman’s menstrual cycle triggers ovulation, which occurs when a prospective mother’s egg is released from her ovary. The follicle stimulating hormone’s role in conception is to stimulate the growth of ovarian follicles before the release of an egg at ovulation. The study’s scientists stopped short of stating that the differences in reproductive hormone production were responsible for marijuana users being 41 percent less likely than the marijuana abstinent women to conceive each cycle. Get Your Medical Card Sign up to get your medical card Sign up to get your medical card What were the study’s limitations? The study’s researchers point out that the percentage of women in the marijuana and pregnancy study that used marijuana (5 percent of participants) and the total number of marijuana users included in the study (62) were so low as to be inconclusive. An introductory questionnaire asked the women enrolling in the study if they had used cannabis products (marijuana or hashish) in the past 12 months. The six responses scaled from never to rarely, occasionally, sometimes, often and daily. All of the 1,200 women were drawn from only four states (Pennsylvania, New York, Utah and Colorado). Each woman submitted a minimum of two urine samples. The first urine sample was provided at the beginning of the study and the follow up sample was turned in at the time of conception by women who became pregnant or at the conclusion of the six month study for women who did not conceive. Of the 62 women who were determined to have used marijuana during the past 12 months, 44 self reported their cannabis use. An additional 18 women who had declined to admit their cannabis use had their marijuana usage exposed by the urine tests. In October 2017 a Committee on Obstetric Practice from the American College of Obstetricians and Gynecologists asserted in the journal Obstetrics & Gynecology that “Seeking obstetric–gynecologic care should not expose a woman to criminal or civil penalties for marijuana use, such as incarceration, involuntary commitment, loss of custody of her children, or loss of housing.” Fear of punishing outcomes may explain the reluctance of women who used marijuana while attempting to become pregnant to reveal their marijuana use to any authority figure or to medical personnel who might be bound by mandatory reporting requirements. The punitive attitude toward prospective mothers using cannabis is not supported by conclusions in the “Cannabis Use While Trying to Conceive” study. Researchers clearly stated that their work does not prove cannabis use impairs fertility. Furthermore, once pregnancy had been achieved, the researchers detected no increase in miscarriage rates in marijuana using women as opposed to among nonusers. The lack of increase in miscarriage rates among cannabis users is an important finding in light of all the women in the study had lost a previous pregnancy to miscarriage. Should Women Trying to Conceive Stop Using Cannabis? We recommend speaking with your primary care physician to get personalized advice. While this study suggests that a woman may find it harder to get pregnant while using cannabis, the use of that cannabis may be offering other medical benefits which are key to the woman’s personal or mental health. At the end of the day, this is a personal choice and there is simply not enough scientific research yet available to provide conclusive evidence for either argument.