This sheet talks about exposure to Omeprazole or Esomeprazole in pregnancy or while breastfeeding. This information should not take the place of medical care and advice from your healthcare provider.

What are omeprazole and esomeprazole?

Omeprazole is a medication used to treat heartburn, stomach ulcers, and acid reflux (also known as GERD, or gastroesophageal reflux disease). It belongs to a group of medicines called proton pump inhibitors (PPIs) that reduce acid released by the stomach. A common brand for omeprazole is Prilosec®. Omeprazole is combined with sodium bicarbonate in a medication called Zegerid®.

The drug esomeprazole (Nexium®) contains the same active medication as omeprazole. Esomeprazole is also a proton pump inhibitor and is used for the same conditions as omeprazole. These two drugs act in the body in a very similar way.

MotherToBaby has a general fact sheet on proton pump inhibitors at

I take omeprazole or esomeprazole. Can it make it harder for me to get pregnant?

It is not known if taking omeprazole or esomeprazole will make it harder for a woman to get pregnant. Studies done in animals show no evidence that omeprazole or esomeprazole could make it harder to get pregnant.

I just found out I am pregnant. Should I stop taking omeprazole or esomeprazole?

Talk with your healthcare provider before making any changes to how you take these medications. *

Does taking omeprazole or esomeprazole increase the chance for miscarriage?

Any woman can have a miscarriage. Studies have not found that taking omeprazole or esomeprazole during pregnancy would increase the chance for miscarriage.

Does taking omeprazole or esomeprazole increase the chance of having a baby with a birth defect?

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. Studies have not suggested that taking omeprazole or esomeprazole during pregnancy would increase the chance for a birth defect.

A few studies found that taking proton pump inhibitors in pregnancy might cause the baby to have asthma as a child. These studies have some flaws that make it difficult to directly link medication use with childhood asthma. In one study, taking omeprazole in pregnancy did not increase the chance of babies having asthma as a child.

Could omeprazole or esomeprazole cause other pregnancy complications?

No studies have looked at this question.

Will taking omeprazole or esomeprazole during pregnancy affect my child’s behavior or cause learning problems?

No studies have looked at this question.

Can I breastfeed my baby if I am taking omeprazole or esomeprazole?

These medicines enter the breastmilk at low levels and are broken down by stomach acid. In a mother taking 20 mg omeprazole per day, no harmful effects were found in the infant. Be sure to talk to your healthcare provider about all of your breastfeeding questions. *

What if the baby’s father takes omeprazole or esomeprazole?

There are no studies looking at risks to a pregnancy when the father takes omeprazole or esomeprazole. 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*

* Section Updated May 2020

Selected References

  • Anderka M, et al. 2012. National Birth Defects Prevention Study. Medications used to treat nausea and vomiting of pregnancy and the risk of selected birth defects. Birth Defects Res A Clin Mol Teratol 94:22-30.
  • Andersen ABT, et al. 2012. Prenatal exposure to acid-suppressive drugs and the risk of toddler asthma: a population-based Danish cohort study. Alim Pharmacol Ther 35:1190-1198.
  • Dehlink E, et al. 2009. First evidence of a possible association between gastric acid suppression during pregnancy and childhood asthma: a population-based register study. Clin Exp Allergy 39:246-53.
  • Diav-Citrin O, et al. 2005. The safety of proton pump inhibitors in pregnancy: a multicentre prospective controlled study. Aliment Pharmacol Ther 21:269-75.
  • Erichsen R, et al. 2014. Maternal use of proton pump inhibitors during early pregnancy and the prevalence of hypospadias in male offspring. Am J Ther 21: 254-259.
  • Gill SK et al. 2009. The safety of proton pump inhibitors (PPIs) in pregnancy: a meta-analysis. Am J Gastroenterol 104(6): 1541-1545.
  • Kallen B. 1998. Delivery outcome after the use of acid-suppressing drugs in early pregnancy with special reference to omeprazole. Br J Obstet Gynaecol 105:877-881.
  • Lalkin A, et al. 1998. The safety of omeprazole during pregnancy: a multicenter prospective controlled study. Am J Obstet Gynecol 179(3 Pt 1): 727-730.
  • Marshall JK, et al. 1998. Omeprazole for refractory gastroesophageal reflux disease during pregnancy and lactation. Can J Gastroenterol 12: 225-227.
  • Matok I, et al. 2012. The safety of fetal exposure to proton-pump inhibitors during pregnancy. Dig Dis Sci 57:699-705.
  • Nikfar S, et al. 2002. Use of proton pump inhibitors during pregnancy and rates of major malformations: a meta-analysis. Dig Dis Sci 47:1526-9.
  • Pasternak B, Hviid A. 2010. Use of proton-pump inhibitors in early pregnancy and the risk of birth defects. N Engl J Med 363:2114-2123.
  • Yitshak-Sade M, et al. 2016. Prenatal exposure to H2 blockers and to proton pump inhibitors and asthma development in offspring. J Clinic Pharmacol 56: 116-123