This sheet talks about using formoterol (eformoterol) in a pregnancy and while breastfeeding. This information should not take the place of medical care and advice from your healthcare provider.

What is formoterol?

Formoterol (also called eformoterol) is a medication used for the treatment of asthma and chronic obstructive pulmonary disease (COPD). It is in a class of medications called long-acting beta2-agonists. Beta2-agonists are bronchodilators. Bronchodilators help to open the airways in the lungs. Formoterol is taken by inhalation (breathing it in). It is usually used in combination with an inhaled corticosteroid for asthma treatment. For information about inhaled corticosteroids, see the MotherToBaby fact sheet at  Formoterol can be found in some combination medications such as Symbicort® and Dulera®.

I take formoterol. Can it make it harder for me to get pregnant?

Studies have not been done to see if formoterol could make it harder for a woman to get pregnant.

I just found out that I am pregnant. Should I stop using my formoterol inhaler?

Talk with your healthcare providers before making any changes to your medication(s). It is important to consider the benefits of controlling asthma symptoms during pregnancy. Untreated asthma increases the chance for complications for both the pregnant woman and the baby. For more information about asthma, please see the MotherToBaby fact sheet at

If a woman’s asthma is well-controlled with formoterol prior to pregnancy, it is considered appropriate to continue its use during pregnancy if needed. When formoterol is inhaled, very limited amounts of the drug enter the blood, and even less is thought to reach the developing baby.

Does taking formoterol increase the chance for miscarriage?

Miscarriage can occur in any pregnancy. There are no published studies looking at whether formoterol increases the chance of miscarriage.

Can taking formoterol increase the chance of birth defects?

In every pregnancy, a woman starts out with a 3-5% chance of having a baby with a birth defect.  This is called her background risk.

There is limited data on the use of formoterol during pregnancy. The information from case reports did not suggest an increased chance of harm.  A study on the use of long acting beta2-agonists (LABA) reported an increased chance for heart defects when used in the first trimester.  However, these results are not conclusive since the pregnant woman’s underlying condition and severity of her asthma symptoms could have influenced the results. While more data is needed on formoterol, it is commonly used during pregnancy in combination with inhaled corticosteroids when asthma symptoms are severe enough to require treatment.

Can taking formoterol during pregnancy cause other pregnancy complications?

One report of 33 women who used formoterol during pregnancy described five cases of birth before 37 weeks of pregnancy (preterm delivery). Three cases of preterm delivery would be expected due to the background risk. Another study compared 162 formoterol-exposed pregnancies to another long acting beta agonist and did not find a difference in birth weight, gestational age or chance of preterm delivery. It is unlikely that the chance for preterm delivery was increased by the use of formoterol during pregnancy. There may be a relationship between preterm delivery and poorly controlled or more severe asthma in pregnancy.

Does taking formoterol in pregnancy cause long-term problems in behavior or learning for the baby?

There are not enough studies on formoterol to know whether there is a chance for long-term problems.

Can I take formoterol while breastfeeding?

There have not been any studies on women taking formoterol while breastfeeding. Information on the use of related medications suggest that the use of a formoterol inhaler would be unlikely to result in high enough levels in the woman’s bloodstream to pass into breast milk in large amounts. Inhaled bronchodilators are generally considered acceptable for use during breastfeeding. Be sure to talk to your healthcare provider about all of your breastfeeding questions.

If a man takes formoterol, could it affect his fertility (ability to get partner pregnant) or increase the chance of birth defects? 

There are no data to suggest a man’s use of formoterol at the time of conception increases the chance for infertility or birth defects. In general, exposures that fathers have are unlikely to increase risks to a pregnancy. For more information, please see the MotherToBaby fact sheet Paternal Exposures at

MotherToBaby is currently conducting a study looking at asthma and the medications used to treat asthma in pregnancy. If you are interested in taking part in this study, please call 1-877- 311-8972 or see

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