CBD is not considered safe if you’re trying to get pregnant. The FDA strongly advises against using CBD, THC, or any cannabis product during pregnancy, and the concerns extend to the preconception period as well. Both female and male fertility can be affected by cannabinoid use, and CBD lingers in the body far longer than most people realize.
Why Health Authorities Advise Against It
The FDA’s position is unambiguous: avoid CBD, THC, and marijuana in any form during pregnancy and breastfeeding. High doses of CBD in pregnant animal studies caused problems with the reproductive system of developing male fetuses. While human data is still limited, the animal findings are concerning enough that the FDA treats CBD as a substance to avoid when reproduction is the goal.
Part of the challenge is that CBD hasn’t been studied extensively in women actively trying to conceive. Most of the human fertility research involves THC or whole-plant cannabis. But CBD interacts with the same endocannabinoid system that plays a role in ovulation, hormone signaling, and embryo development, which means the biological plausibility for harm is real even where direct human studies are thin.
How Cannabis Compounds Affect Female Fertility
Cannabis use disrupts the hormonal chain reaction that triggers ovulation. It suppresses the brain’s release of gonadotropin-releasing hormone, which in turn reduces production of estrogen, progesterone, and two key fertility hormones: follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Without adequate levels of these hormones, your ovaries may not release an egg at all.
The numbers bear this out. In one study, women who used cannabis at least three times per week had anovulatory cycles (cycles with no egg release) or abnormally short luteal phases at a rate of 38.3%, compared to 12.5% in non-users. Even occasional use, defined as one to three times over three months, was associated with a follicular phase that lasted 3.5 days longer than normal, meaning ovulation was delayed. A single session of inhaled cannabis was enough to suppress LH levels during the luteal phase of the menstrual cycle.
When FSH is suppressed, the downstream effects include reduced follicle development, impaired egg maturation, and lower production of the sex hormones needed to sustain a pregnancy in its earliest days. For someone timing intercourse or planning fertility treatments, these disruptions can meaningfully reduce the odds of conception each cycle.
Effects on Male Fertility
If your partner uses cannabis, their fertility may also take a hit. A systematic review in the Journal of Urology found that cannabis reduces sperm count, concentration, motility, viability, and the sperm’s ability to fertilize an egg.
Among chronic users who smoked ten or more times per week, average sperm concentration dropped to 26.6 million per milliliter, compared to 67.9 million in men who smoked five to nine times weekly. Men who used cannabis more than once a week had 28% lower sperm concentration and 29% lower total sperm count than men who had never used it. Men under 30 who used cannabis in the three months before providing a semen sample were nearly twice as likely to have abnormal sperm shape, defined as fewer than 4% of sperm having normal form.
Sperm motility, meaning how well sperm swim, also declines. Lab studies showed motility dropped by 28% at low THC concentrations and by 56% at higher concentrations. A similar decrease appeared in semen samples from chronic cannabis users after just four weeks of heavy use.
What Animal Studies Show About Prenatal CBD Exposure
Research published in Translational Psychiatry found that mouse pups exposed to CBD in the womb showed sex-specific changes in early behavior and development. Males exposed to CBD in utero produced shorter vocalizations, while exposed females vocalized at higher frequencies. Both sexes showed a less complex vocal repertoire, producing fewer of the composite calls that are markers of normal neurological development. CBD-exposed females also showed reduced motor activity and altered responses to unfamiliar environments.
The researchers noted that the communication changes resembled patterns seen in mouse models of autism spectrum disorders. They concluded that their findings “challenge the idea that CBD is a universally safe compound” and pointed to the need for more research on what prenatal CBD exposure does to developing brains. These are animal findings, not direct proof of the same effects in humans, but they raise a flag that CBD exposure around conception and early pregnancy carries biological risks that aren’t fully understood.
CBD Stays in Your Body Longer Than You Think
One critical detail for anyone planning to stop CBD before trying to conceive: it takes a long time to clear your system. CBD’s terminal elimination half-life in humans exceeds 134 hours, which is more than five and a half days. That means it takes several weeks for levels to drop substantially after you stop taking it. For people who have been taking CBD daily, plasma levels don’t reach steady state until more than 70 days of consistent dosing, and the reverse is also true. The compound distributes extensively into body tissues and releases back into the bloodstream slowly.
This means stopping CBD a few days before ovulation isn’t enough. If you’re planning to conceive, you’d want to discontinue use well in advance, potentially several weeks or more, to allow meaningful clearance from your tissues.
CBD Products Often Contain More Than CBD
Even if CBD itself posed no risk, the products on the market introduce additional concerns. A 2024 analysis of 202 commercial CBD products found heavy metals in 44 of them. Lead was the most common contaminant, detected in 42 products, with five exceeding regulatory safety thresholds. Arsenic appeared in six samples and cadmium in four. Pesticides were found 55 times across 30 products, spanning 26 different chemicals.
Some products labeled as THC-free actually contained THC. Three broad-spectrum products tested positive, and two of those exceeded the 0.3% THC threshold. Because the CBD market is largely unregulated, there’s no reliable way to know exactly what’s in a given product. For someone trying to conceive, this means even a product marketed as “pure CBD” could expose you to THC, heavy metals like lead, or pesticide residues, all of which carry their own reproductive risks.
What This Means for Your Timeline
If you’re actively trying to get pregnant or plan to start soon, the safest approach based on current evidence is to stop using CBD products. Given CBD’s long elimination time of over 134 hours per half-life, stopping several weeks before you begin trying gives your body time to clear the compound from tissues. The same applies to your partner if they use cannabis or CBD products, since sperm take roughly 74 days to fully develop, and exposure during that window can affect the sperm available at conception.
The core issue isn’t that CBD has been proven to cause specific birth defects or infertility at typical consumer doses. It’s that the compound affects the hormonal and endocannabinoid systems that govern reproduction, that animal studies show concerning developmental effects, and that the human safety data simply doesn’t exist yet. When the goal is conception and a healthy pregnancy, that uncertainty is the problem.