Marijuana use during pregnancy has been linked to several alarming risks for both the mother and her unborn child, according to a recent meta-analysis. The dangers of prenatal cannabis include poor fetal development, dangerously early deliveries, low birth weight, and even perinatal mortality. With growing research highlighting the risks, it’s important for expectant mothers to understand how prenatal cannabis exposure may affect their baby’s health.

How Marijuana Use Affects the Developing Fetus

The placenta is a vital connection between a mother and her fetus, delivering oxygen, nutrients, and hormones essential for growth. However, marijuana use can damage this link, reducing blood flow and oxygen delivery to the fetus. This can impact lung function and overall development of the baby, says Dr Jamie Lo, lead author of the study published in JAMA Pediatrics.

“Prior work shows prenatal cannabis use affects fetal lung function and development, reducing the baby’s lung volume,” Dr Lo explains. These changes, combined with compromised oxygen supply, could explain why marijuana use during pregnancy has severe consequences.

Rise in Marijuana Use Among Pregnant Women

Despite the risks, marijuana use among pregnant women has steadily increased. A 2019 study by the National Institute on Drug Abuse reported that cannabis use among pregnant women aged 12 to 44 more than doubled between 2002 and 2017. Most of this use occurred in the early stages of pregnancy and was recreational rather than medically prescribed.

Many women believe that because marijuana is plant-based, it is safe. But as Dr Lo points out, “Opium, heroin, and tobacco are also plant-based. ‘Natural’ doesn’t mean safe, especially during pregnancy.”

Key Risks of Marijuana Use During Pregnancy

Increased Risk of Preterm Delivery

Marijuana use during pregnancy increases the likelihood of preterm delivery by 52%. A baby is considered preterm if born before 37 weeks of gestation. Since full-term pregnancies allow for complete fetal development, early delivery can lead to numerous health issues for the baby, including breathing difficulties, developmental delays, and long-term health challenges.

Low Birth Weight

Infants exposed to marijuana in the womb face a 75% higher risk of being born with low birth weight (defined as under 5.5 pounds or 2,500 grams). Babies born with low birth weight are more likely to face complications such as infections, breathing difficulties, and poor temperature regulation.

Perinatal Mortality

Perhaps the most alarming finding of the study was the association between marijuana use during pregnancy and a 29% higher risk of perinatal mortality. This term refers to death that occurs during pregnancy or shortly after birth. Such outcomes underline the severe consequences cannabis use can have on fetal and infant life.

Why Research on Prenatal Cannabis is Still Developing

Unlike alcohol or tobacco, public health messaging around the dangers of prenatal cannabis has been inconsistent. Part of the reason stems from the limited research historically available. Much of the older data on marijuana dates back to the 1980s, when cannabis had significantly less potency than it does today. Legal and regulatory hurdles have also slowed down research into the effects of the drug.

However, recent developments are improving the quality of evidence. The new meta-analysis utilised the GRADE (grading of recommendations assessment, development, and evaluation) approach to assess 51 studies covering over 21 million participants. This review reinforces the connection between prenatal cannabis exposure and adverse health outcomes, giving researchers more confidence in advising against its use.

Common Misconceptions About Marijuana Use in Pregnancy

The Natural Fallacy

The belief that natural products are inherently safe is a dangerous myth, particularly when it comes to marijuana use during pregnancy. Substances like tobacco, alcohol, and opium share their natural origins with cannabis yet have well-documented harmful effects on fetuses.

Conflicting Information

The legalisation and increased availability of marijuana have also blurred perceptions of its safety. Many healthcare providers have expressed difficulty counselling patients due to conflicting studies and outdated information.

Dr Lo highlights the need for clearer communication, “We’re working to bolster public health messaging and provide clinicians with evidence-based guidelines to better advise their patients.”

Long-Term Risks of Prenatal Cannabis Exposure

Beyond the immediate risks to fetal development, marijuana use during pregnancy has been linked to long-term consequences for children. Research shows that prenatal cannabis exposure can affect cognitive development, leading to attention deficits, social challenges, and weaker problem-solving skills.

Additionally, exposure to marijuana in utero has been associated with higher risks of mental health issues, including anxiety and psychotic-like behaviours, later in life. The impacts may persist into adolescence and adulthood, highlighting why avoiding cannabis during pregnancy is crucial.

Public Health Messaging Around Marijuana Use

While researchers are making strides in understanding the dangers of prenatal cannabis, public health education is yet to catch up. Mixed messages about marijuana’s safety, coupled with its increasing normalisation, make it harder for pregnant women to make informed decisions.

Experts stress that clearer, evidence-based campaigns are needed to close the gap and ensure expectant parents understand the risks.

Making Informed Choices During Pregnancy

If you are pregnant or planning to conceive, avoiding marijuana is one proactive step you can take to protect your baby’s health. With research evolving and improving, the evidence increasingly supports that steering clear of cannabis during pregnancy is the safest option.

Healthcare providers should also continue striving for consistency in their advice, using the growing body of research to guide their discussions with expectant mothers.

Source: CNN