Marijuana vs CBD in Pregnancy: What's Safer?
Neither marijuana nor CBD is proven safe in pregnancy. CBD is not risk-free, and no cannabis product is recommended while pregnant.
Short answer: Roughly 7 in 100 pregnant people in the U.S. say they used cannabis recently, and the share runs higher in early pregnancy, about 1 in 8 during the first trimester. Large health system studies put the number in a similar range. The honest caveat is that self-reports miss people who don't disclose use, so the true rate is probably higher than the headline figure.
How common is THC use during pregnancy?
The most cited national estimate comes from survey data summarized by the National Institute on Drug Abuse: about 7% of pregnant people self-report cannabis use. Use is not spread evenly across pregnancy. It peaks in the first trimester, when many people don't yet know they're pregnant or haven't told a clinician, then drops as pregnancy progresses.
Cannabis Use During Pregnancy: Third Trimester Guide
Age matters a lot. Among pregnant people under 25, reported use runs several points higher than the overall figure, and some surveys put it near 15% to 19%. That tracks with cannabis use patterns in the general population, where young adults report the highest rates.
is cannabis safe during pregnancy
Trend data tells the more useful story. In a Kaiser Permanente Northern California cohort of more than 250,000 pregnancies, self-reported use rose from 4.2% in 2009 to 7.1% in 2016. California had legal medical cannabis for that whole window and legal adult use for part of it, and the upward slope showed up in both self-report and urine testing.
is cannabis safe during pregnancy
Self-report versus lab testing
Ask people and you get one number. Test their urine and you get another. When researchers in that same Kaiser cohort checked urine toxicology alongside questionnaires, the tested rate was consistently higher, sometimes close to double the self-reported rate. Part of that gap is disclosure. Part is timing: THC metabolites linger for weeks, so a positive test can reflect use that happened before pregnancy was confirmed.
That gap matters for reading any statistic you see. A study using birth certificate data, a study using anonymous surveys, and a study using universal urine screening are all measuring different things.
Who the statistics describe
- People under 25 report the highest rates of prenatal cannabis use.
- States with legal adult-use cannabis tend to show higher prenatal use than states without it, though the effect is modest and uneven.
- Co-use with tobacco or alcohol is common in the data, which makes it hard to separate the effects of THC alone.
- Unplanned pregnancy and limited prenatal care access show up as risk factors in several large studies.
- People using cannabis for nausea, anxiety, or sleep often don't think of it as a risk behavior, so they may not mention it at a prenatal visit.
Why the numbers vary so much
Screening practice is the biggest driver. Some clinics ask every patient at the first prenatal visit. Others only test when there's a clinical reason. Anonymity changes answers too: people tell a research survey things they don't tell a nurse who is documenting in a chart. State law and mandated reporting add another layer, and in some places a positive screen can trigger a child protective services referral, which is a real reason people stay quiet.
What the statistics do not tell you
They don't establish a safe amount, because no study has found one. They don't prove causation either. Prenatal cannabis research is almost entirely observational, and cannabis use correlates with tobacco use, socioeconomic stress, mental health conditions, and other factors that affect birth outcomes on their own.
What the observational data does show is an association with lower birth weight, preterm birth, and higher NICU admission rates in some cohorts, with mixed or small effects in others. The American College of Obstetricians and Gynecologists states that no amount of cannabis has been shown safe in pregnancy and recommends screening and counseling at the first prenatal visit. THC crosses the placenta and has been detected in umbilical cord tissue, which is why the concern isn't theoretical.
Breastfeeding gets the same answer: THC passes into milk, and both ACOG and the AAP suggest avoiding cannabis while nursing.
What to do with this information
If you're pregnant and using THC, the useful move is to tell your clinician plainly, including how much and how often. The conversation is more productive than the number on a survey. Most prenatal providers would rather adjust nausea treatment or sleep support than have you manage it alone and skip the conversation entirely.