This sheet talks about using montelukast in a pregnancy and while breastfeeding. This information should not take the place of medical care and advice from your healthcare provider.
What is montelukast?
Montelukast is an asthma and allergy medication that is taken by mouth. Montelukast works by blocking a group of chemicals in the body called leukotrienes. Leukotrienes cause inflammation (swelling) of the airways, which can make it hard to breath. Montelukast is used to help control allergy symptoms and to make an asthma attack less likely. It is not used to stop an asthma attack. Montelukast is sold under the brand name Singulair®.
I take montelukast. Can it make it harder for me to get pregnant?
It is not known if montelukast could make it harder to get pregnant.
I just found out I am pregnant. Should I stop taking montelukast?
Talk with your healthcare providers before making any changes to how you take your medication(s).
Montelukast has been less studied during pregnancy than some other asthma medications. However, if montelukast helped control your asthma before pregnancy, it may be appropriate to continue using it in pregnancy.
It is important to think about the benefits of controlling asthma symptoms during pregnancy. Untreated asthma increases the chance for complications for the person who is pregnant as well as the baby. For more information, please see the MotherToBaby fact sheet on asthma at https://mothertobaby.org/fact-sheets/asthma-and-pregnancy/pdf/.
Does taking montelukast increase the chance for miscarriage?
Miscarriage can occur in any pregnancy. It is unknown if montelukast increases the chance for miscarriage.
Does taking montelukast increase the for chance birth defects?
Every pregnancy starts out with a 3-5% chance of having a birth defect. This is called the background risk. Based on the available information, the use of montelukast during pregnancy is not expected to increase the chance for birth defects above the background risk.
The manufacturer of montelukast reported a possible association with limb defects (problems with fingers, toes, arms or legs). However, only a few cases of limb defects were reported. The types of limb defects in the report were different from one another, which suggest they do not have a common cause such as an exposure to a particular medication. Also, these children were exposed to other medications during pregnancy. Medical record reviews of thousands of pregnancies reportedly exposed to montelukast did not find any cases of limb defects or other birth defects. Also, there have been two studies looking at 276 pregnancies exposed to montelukast that have not supported an increased chance for birth defects.
Could taking montelukast cause other pregnancy complications?
A few studies have reported a chance for some pregnancy complications when montelukast was used during pregnancy, such as: lower birth weight, preterm delivery (delivery before 37 weeks of pregnancy), and preeclampsia (a disorder that can cause high blood pressure and protein in the urine). However, these could also be the due to more severe or poorly controlled asthma and not the montelukast itself. The people in these studies who needed montelukast often had severe asthma and sometimes needed more than one medication. One study did not notice a difference in birth weight of babies exposed to montelukast when compared to babies exposed to other asthma treatments.
Does taking montelukast in pregnancy cause long-term problems in behavior or learning for the baby?
It is unknown if montelukast could cause long-term behavior or learning issues.
Can I breastfeed while taking montelukast?
There are no studies looking at effects in newborns who are exposed to montelukast through breastmilk. Montelukast is thought to pass into breast milk in very low levels. One study found that nursing infants would likely receive less of the medication in breastmilk than the dose used to treat an infant; thus, the risk to a nursing baby is likely to be low. Talk with your healthcare provider about all of your breastfeeding questions.
I take montelukast. Can it make it harder for me to get my partner pregnant or increase the chance of birth defects?
There are no studies looking at paternal use of montelukast before to or at the time of conception. 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 on Paternal Exposures at https://mothertobaby.org/fact-sheets/paternal-exposures-pregnancy/pdf/.
MotherToBaby is currently conducting a study looking at asthma and the medications used to treat asthma in pregnancy. If you are interested in learning more, please call 1-877-311-8972 or visit https://mothertobaby.org/join-study.
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