This sheet is about exposure to olanzapine in pregnancy and while breastfeeding. This information is based on available published literature. It should not take the place of medical care and advice from your healthcare provider.
What is olanzapine?
Olanzapine is a medication that has been used to treat schizophrenia, major depressive disorder, mixed or maniac episodes, and bipolar disorder. It has also been used with other medications to treat anorexia, depression and symptoms of dementia. A brand name for olanzapine is Zyprexa®.
Sometimes when women find out they are pregnant, they think about changing how they take their medication, or stopping their medication altogether. However, it is important to talk with your healthcare providers before making any changes to how you take your medication. Your healthcare providers can talk with you about the benefits of treating your condition and the risks of untreated illness during pregnancy. MotherToBaby has a fact sheet on depression here: https://mothertobaby.org/fact-sheets/depression-pregnancy/.
Some women may have a return of their symptoms (relapse) if they stop this medication during pregnancy. If you plan to stop this medication, your healthcare provider may suggest that you slowly lower the dose instead of stopping all at once. Stopping this medication suddenly can cause some people to have withdrawal symptoms. It is not known if or how withdrawal symptoms might affect a pregnancy.
I take olanzapine. Can it make it harder for me to get pregnant?
In some women, olanzapine may raise the levels of the prolactin hormone. High levels of prolactin can stop ovulation (part of the menstrual cycle when an ovary releases an egg). This would make it harder to get pregnant. Your healthcare provider can test your levels of prolactin if there is concern.
Does taking olanzapine increase the chance of miscarriage?
Miscarriage is common and can occur in any pregnancy for many different reasons. It is not known if olanzapine can increase the chance of miscarriage. Some conditions, such as depression, might increase the chance of miscarriage. This makes it hard to know if a medication, the medical condition being treated, or other factors increases the chance of miscarriage.
Does taking olanzapine increase the chance of birth defects?
Every pregnancy starts out with a 3-5% chance of having a birth defect. This is called the background risk. Studies looking at over 2500 babies exposed to olanzapine during early pregnancy or throughout pregnancy suggest that olanzapine use is unlikely to increase the chance of birth defects.
Does taking olanzapine in pregnancy increase the chance of other pregnancy-related problems?
It is not known if olanzapine can increase the chance of other pregnancy-related problems, such as preterm delivery (birth before week 37) or low birth weight (weighing less than 5 pounds, 8 ounces [2500 grams] at birth). A study from 2000 suggested that olanzapine therapy was associated with low birth weight and infants needing care in the neonatal intensive care unit (NICU). However, more recent studies have not reported an increased chance of these outcomes. One small study did not find an increased chance of preterm delivery.
Some studies suggest that taking olanzapine throughout pregnancy may increase the chance of gestational diabetes. Gestational diabetes can increase the chance for other complications such as preterm delivery or the fetus being larger than expected (called macrosomia). Talk with your healthcare provider about your risk for gestational diabetes. If needed, they can monitor your blood sugar levels before and during pregnancy. More information about gestational diabetes can be found in our fact sheet at https://mothertobaby.org/fact-sheets/diabetes-pregnancy/.
Research has also shown that when conditions such as depression are left untreated during pregnancy, there could be an increased chance for pregnancy complications. This makes it hard to know if a medication, the medical condition being treated, or other factors are increasing the chance for these problems.
I need to take olanzapine throughout my entire pregnancy. Will it cause withdrawal symptoms in my baby after birth?
The use of olanzapine during pregnancy can cause temporary symptoms in newborns soon after birth. These symptoms are sometimes referred to as withdrawal. Symptoms can include stiff or floppy muscle tone, drowsiness, agitation, trouble with breathing, trouble with feeding, or tremors. Symptoms usually go away in a few days. Not all babies exposed to olanzapine will have these symptoms. It is important that your healthcare providers know you are taking olanzapine so that if symptoms occur your baby can get the care that is best for them.
Does taking olanzapine in pregnancy affect future behavior or learning for the child?
It is not known if olanzapine can increase the chance of behavior or learning issues for the child. Information is limited, and no proven link between prenatal exposure to olanzapine and effects on future behavior or learning in the exposed children has been established.
Breastfeeding while taking olanzapine:
Olanzapine passes into breastmilk in small amounts. Side effects were not reported in most infants exposed to olanzapine through breastmilk. In one study, symptoms such as irritability, tremors, being more sleepy than usual, having trouble sleeping or staying asleep were reported in a small number of infants. If you suspect the baby has any symptoms (irritability, tremors, or having any sleep problems), contact the child’s healthcare provider. Be sure to talk to your healthcare provider about all your breastfeeding questions.
If a man takes olanzapine, could it affect fertility or increase the chance of birth defects?
Using olanzapine may raise a man’s levels of the prolactin hormone, which may affect fertility (ability to get partner pregnant). Studies have not been done to see if olanzapine could increase the chance of birth defects above the background risk. In general, exposures that fathers or sperm donors have are unlikely to increase the risks to a pregnancy. For more information, please see the MotherToBaby fact sheet Paternal Exposures at https://mothertobaby.org/fact-sheets/paternal-exposures-pregnancy/.
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