Benzodiazepines and Birth Defect Risks: What Pregnant Women Need to Know

When you're pregnant and struggling with anxiety or insomnia, the last thing you want is to feel like you have to choose between your mental health and your baby’s safety. But if you’re taking benzodiazepines - drugs like alprazolam, lorazepam, or diazepam - you’re facing real questions. Are these medications safe? Could they cause birth defects? What does the science actually say?

The truth isn’t simple. Some studies show clear risks. Others show little to no danger. And yet, more than 1 in 60 pregnant women in the U.S. are prescribed these drugs during the first trimester. That’s not rare. It’s common enough that every expectant parent should understand the facts - not just the headlines.

What Are Benzodiazepines, and Why Are They Used in Pregnancy?

Benzodiazepines are a class of drugs developed in the 1950s to treat anxiety, panic attacks, seizures, and severe insomnia. They work by calming overactive brain signals. For some women, untreated anxiety during pregnancy can be just as dangerous as the medication itself - leading to poor nutrition, high blood pressure, or even preterm labor.

But here’s the catch: benzodiazepines cross the placenta. They don’t stay in the mother’s bloodstream. They reach the baby. And because fetal tissues are still forming, especially in the first 12 weeks, even small amounts can interfere with development.

What Birth Defects Are Linked to Benzodiazepines?

Not all birth defects are equally likely. The data shows some risks are real - and specific.

A major 2022 study in PLOS Medicine tracking over 3 million pregnancies in South Korea found a small but real increase in overall birth defects when benzodiazepines were taken in the first trimester. The biggest jump? Heart defects. For every 1,000 women using these drugs, about 14 more babies had heart problems compared to those who didn’t.

But it gets more specific. The CDC’s long-running National Birth Defects Prevention Study found startling links between alprazolam and three rare but serious conditions:

• Dandy-Walker malformation - a brain defect affecting fluid drainage and balance (3.1 times higher risk)
• Anophthalmia or microphthalmia - missing or abnormally small eyes (4 times higher risk with alprazolam)
• Esophageal atresia - a blockage in the tube connecting the throat to the stomach (2.7 times higher risk with alprazolam)

These aren’t theoretical. These are real numbers from real pregnancies. And they’re not random. Alprazolam - commonly sold as Xanax - kept showing up as the strongest link. That’s important. Not all benzodiazepines are the same.

What About Other Risks Beyond Birth Defects?

Birth defects aren’t the only concern. Benzodiazepines are linked to other serious outcomes:

• 85% higher risk of miscarriage - according to a 2024 JAMA Psychiatry study
• Increased chance of preterm birth - babies born before 37 weeks
• Low birth weight - babies weighing less than 5.5 pounds
• Neonatal withdrawal - newborns can be jittery, irritable, or have trouble feeding if the mother used these drugs late in pregnancy
• Higher NICU admission rates - babies may need extra care after birth

And it’s not just exposure during pregnancy. One study found women who took benzodiazepines in the 90 days before conception had a higher risk of ectopic pregnancy - meaning the embryo implants outside the uterus. That’s a red flag that these drugs might affect fertility or early development even before you know you’re pregnant.

How Big Is the Actual Risk?

Let’s put numbers to fear. A 30% increase sounds scary - until you see what it means in real terms.

In unexposed pregnancies, about 2.87 out of every 100 babies have a major birth defect. With benzodiazepine use, that number rises to 3.81. That’s an extra 0.94 cases per 100 pregnancies. For heart defects, it’s about 14 extra cases per 1,000 births. For rare defects like anophthalmia? The baseline risk is about 1 in 10,000. With alprazolam, it jumps to roughly 4 in 10,000.

That’s still rare. But rare doesn’t mean harmless. And when you’re carrying a child, even small risks matter.

Why Do Some Studies Say There’s No Risk?

You’ve probably heard conflicting things. One study says yes, another says no. That’s because of something called “confounding by indication.”

Here’s how it works: Women who take benzodiazepines during pregnancy often have severe anxiety, depression, or chronic insomnia. Those conditions themselves - not the drugs - can increase the risk of preterm birth or low birth weight. So if a study doesn’t properly separate the effects of the drug from the effects of the illness, it looks like the drug is harmless.

The 2022 PLOS Medicine study tackled this head-on. They compared women who took benzodiazepines with women who didn’t - but also matched them by severity of anxiety, age, income, smoking status, and other factors. Even then, the risks remained. That’s why experts now take this study seriously. It’s the largest, most carefully designed one so far.

What Do Experts Actually Recommend?

Guidelines are clear: avoid benzodiazepines in the first trimester if you can.

The American College of Obstetricians and Gynecologists (ACOG) says these drugs “may be used cautiously for short-term treatment” - but only after other options fail. The European Medicines Agency says to avoid them entirely in early pregnancy. Canada’s guidelines say the same: “Generally avoid.”

And here’s the most important part: Do not stop taking benzodiazepines suddenly. Quitting cold turkey can trigger seizures, severe anxiety, or even psychosis - which are dangerous for both you and your baby.

If you’re on benzodiazepines and planning a pregnancy - or just found out you’re pregnant - talk to your doctor. Together, you can:

1. Review which drug you’re taking (alprazolam carries the highest risk)
2. Assess your dose (higher doses = higher risk)
3. Consider safer alternatives like cognitive behavioral therapy (CBT) for anxiety or sleep hygiene for insomnia
4. Gradually taper off, if needed, under medical supervision

What Are the Safer Alternatives?

You don’t have to suffer in silence. There are effective, drug-free options:

• Cognitive Behavioral Therapy (CBT) - proven to reduce anxiety and insomnia as effectively as medication, with no risk to the baby
• Mindfulness and meditation - studies show they lower stress hormones and improve sleep quality
• Regular exercise - even 20 minutes of walking a day improves mood and sleep
• Improved sleep hygiene - no screens before bed, consistent bedtime, cool dark room
• Support groups - connecting with other pregnant women who’ve been there helps reduce isolation

Some antidepressants - like sertraline - are considered safer than benzodiazepines during pregnancy. But again, it’s not one-size-fits-all. Your mental health history, symptoms, and past responses to treatment all matter.

What Should You Do Right Now?

If you’re currently taking a benzodiazepine and pregnant:

• Don’t panic. The absolute risk is low, even if the relative risk is higher.
• Don’t stop suddenly. This can be dangerous.
• Call your doctor. Ask: “Is this the right drug for me right now? Is my dose the lowest possible? Are there safer options?”
• Start non-drug strategies today. Even small changes can help reduce your need for medication.

If you’re trying to get pregnant and taking benzodiazepines:

• Start planning now. Tapering safely takes weeks or months.
• Work with a psychiatrist and an OB-GYN together.
• Consider therapy before conception - it’s easier to build skills before pregnancy hits.

What About Breastfeeding?

Some benzodiazepines pass into breast milk. But the amounts are usually very small. Short-acting ones like lorazepam and oxazepam are preferred over long-acting ones like diazepam. Still, watch your baby for signs of drowsiness, poor feeding, or breathing trouble. If you notice anything unusual, call your pediatrician.

Many mothers successfully breastfeed while on low-dose, carefully managed benzodiazepines. But again - it’s not risk-free. The safest path is to reduce or eliminate use before delivery if possible.