Clonazepam is not considered safe during pregnancy. The FDA classifies it as Pregnancy Category D, meaning there is positive evidence of risk to the fetus. That said, the decision to continue or stop is not always straightforward, particularly for people who take clonazepam for seizure disorders or severe panic disorder. Stopping abruptly carries its own serious risks, so this is a decision that requires careful planning with a provider.
Why the FDA Labels It Category D
The FDA’s prescribing label for clonazepam (brand name Klonopin) states plainly that data “raise concerns about the use of Klonopin during pregnancy.” The label warns that benzodiazepines as a class are assumed capable of causing congenital abnormalities when taken during the first trimester and that first-trimester use “should almost always be avoided” for panic disorder. The language is unusually direct for a drug label: if pregnancy occurs while taking clonazepam, “the patient should be apprised of the potential hazard to the fetus.”
Risk of Miscarriage
A 2025 meta-analysis published in BMC Pregnancy and Childbirth found that benzodiazepine use during pregnancy was linked to a 68% increased risk of miscarriage overall. Clonazepam specifically carried one of the higher estimates in the class, with a pooled odds ratio of 1.82 across three studies. That means the odds of miscarriage were roughly 82% higher among clonazepam users compared to non-users. While observational studies like these can be influenced by the underlying conditions being treated, the finding was consistent across multiple benzodiazepines, suggesting a class-wide effect.
Birth Defect Risk in the First Trimester
The National Birth Defects Prevention Study, conducted through the CDC, looked at whether first-trimester benzodiazepine exposure increased the risk of specific malformations. For clonazepam specifically, the data did not show a clear increase in oral clefts or heart defects. The odds ratios for cleft lip and cleft palate were 1.0 and 1.6 respectively, but the confidence intervals were wide and consistent with no real association. Similarly, the odds ratio for pulmonary valve stenosis (a type of heart defect) was 1.2, again statistically indistinguishable from no effect.
Other benzodiazepines in the study showed stronger signals. Alprazolam, for instance, was more clearly linked to certain esophageal and eye defects. Lorazepam was associated with a roughly fourfold increase in one type of heart valve defect. So while clonazepam’s birth defect profile appears somewhat less alarming than some of its relatives, the study was limited by small numbers of exposed cases, making it hard to rule out modest risks.
Problems in Late Pregnancy
Taking clonazepam in the third trimester poses a different set of concerns. The drug crosses the placenta and can affect the baby’s nervous system directly. This can lead to what’s called “floppy infant syndrome,” where the newborn has low muscle tone, breathing difficulties, and trouble feeding. Clonazepam works by amplifying the brain’s main calming chemical (GABA), which reduces the excitability of nerve cells. In a newborn whose nervous system is still immature, this sedating effect can cause significant problems including episodes of apnea (pauses in breathing) and a blue tinge from low oxygen.
Babies exposed late in pregnancy can also experience withdrawal symptoms, typically appearing 8 to 48 hours after birth. Common signs include irritability, tremors, and feeding difficulties. These symptoms generally last 2 to 6 days, though in some cases they can persist for weeks. One case report described a premature infant with repeated episodes of prolonged apnea and abnormal breathing that continued up to 10 weeks of age, though the child’s neurodevelopment was normal by 5 months.
Longer-Term Effects on Child Development
A large nationwide cohort study tracked over 1.5 million births and compared children exposed to benzodiazepines prenatally with matched unexposed children. Neurodevelopmental disorders (a broad category that includes conditions like ADHD, autism spectrum disorder, and intellectual disabilities) occurred in 13.9% of exposed children versus 11.4% of unexposed children, a roughly 25% relative increase in risk.
The risk appeared to increase with longer exposure: children exposed for 30 days or more had about an 18% higher odds than unexposed children, while those exposed during the second or third trimester showed increases of 27 to 30%. Importantly, when researchers compared siblings where one was exposed and the other was not, the association held up, suggesting the effect isn’t fully explained by genetics or family environment. These are modest increases in absolute terms, but they represent a meaningful signal that prenatal exposure may have lasting consequences for brain development.
Why You Should Not Stop Suddenly
If you’re currently taking clonazepam and discover you’re pregnant, do not stop the medication on your own. Abruptly discontinuing any benzodiazepine can trigger withdrawal seizures, which are dangerous for both you and the pregnancy. The safe approach is a gradual, supervised taper. In some cases, a provider may switch you to a longer-acting benzodiazepine that can be reduced more smoothly. The goal is to reach the lowest effective dose, or ideally to discontinue entirely, but the timeline matters as much as the destination.
Alternatives for Anxiety During Pregnancy
For anxiety and panic disorder, SSRIs are generally considered the first-line medication option during pregnancy. Sertraline is one of the most commonly recommended because of its relatively well-studied safety profile in pregnant populations. Non-medication approaches also play a role: cognitive behavioral therapy, regular exercise, and structured relaxation techniques can be effective for some people, either alone or alongside medication. These alternatives aren’t always sufficient for severe anxiety or seizure disorders, which is why the decision is individualized rather than one-size-fits-all.
Clonazepam and Breastfeeding
Clonazepam does pass into breast milk, though in small amounts. One study measured a maximum infant dose of about 2.5% of the mother’s weight-adjusted dose. At that level, most infants tolerate it without obvious problems. In a group of 11 breastfeeding mothers taking between 0.25 and 2 mg daily, none reported side effects in their infants.
However, sedation is a real concern. Out of 174 reports in one safety database, clonazepam was suspected in serious adverse reactions in 5 infants, primarily excessive sleepiness. One well-documented case involved a two-month-old with hypotonia, somnolence, and apnea directly attributed to clonazepam in breast milk. Because clonazepam has a long half-life, it can accumulate in a newborn’s system more than a shorter-acting alternative would. If breastfeeding while taking clonazepam, watch for unusual drowsiness, poor feeding, and slow weight gain, particularly in the first few weeks of life.