Is omeprazole (proton pump inhibitor) safe to use during pregnancy?

From the Guidelines

Omeprazole is considered safe to use during pregnancy when medically necessary, as stated in the 2019 guidelines published in the Annals of Oncology 1.

Key Points to Consider

• The guidelines recommend that proton pump inhibitors, including omeprazole, can be used if necessary during pregnancy.
• It is essential to use the lowest effective dose for the shortest duration needed to minimize potential risks.
• Pregnant women with severe gastroesophageal reflux disease (GERD), erosive esophagitis, or other conditions requiring acid suppression may be prescribed omeprazole after lifestyle modifications and antacids have failed.
• Typical dosing ranges from 20-40 mg daily, but this should be determined by a healthcare provider based on individual needs.
• First-line treatments for pregnancy-related heartburn should include lifestyle changes and safer medications like antacids or sucralfate.
• If a proton pump inhibitor is needed, some providers prefer lansoprazole or rabeprazole, which have more pregnancy safety data, but omeprazole is still considered a viable option when necessary, as indicated by the guidelines 1.
• Theoretical concerns with omeprazole include potential vitamin B12 deficiency with prolonged use and altered absorption of iron or calcium, which are important during pregnancy.
• Women should always consult their healthcare provider before taking any medication during pregnancy to weigh individual risks and benefits.

Additional Considerations

• The 2020 European Respiratory Journal guidelines 1 provide information on various medications during pregnancy but do not specifically address omeprazole safety in detail.
• However, the primary consideration for omeprazole use during pregnancy is based on the most recent and relevant guidelines, which support its safe use when medically necessary, as mentioned in the Annals of Oncology 1.

From the FDA Drug Label

There are no adequate and well-controlled studies with omeprazole in pregnant women. Available epidemiologic data fail to demonstrate an increased risk of major congenital malformations or other adverse pregnancy outcomes with first trimester omeprazole use The estimated background risks of major birth defects and miscarriage for the indicated population are unknown. All pregnancies have a background risk of birth defect, loss or other adverse outcomes. In the U. S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively

Omeprazole use in pregnancy is not supported by adequate and well-controlled studies. However, available epidemiologic data do not demonstrate an increased risk of major congenital malformations or other adverse pregnancy outcomes with first trimester omeprazole use.

• The background risk of major birth defects in the U.S. general population is estimated to be 2% to 4%.
• The background risk of miscarriage in the U.S. general population is estimated to be 15% to 20%. Given the lack of adequate and well-controlled studies, omeprazole should be used in pregnancy only if clearly needed 2.

From the Research

Omeprazole Safety in Pregnancy

• The safety of omeprazole, a proton pump inhibitor, during pregnancy has been evaluated in several studies 3, 4, 5, 6.
• A study published in the Canadian journal of gastroenterology reported the use of omeprazole in a 41-year-old female during the third trimester of pregnancy, with no adverse fetal effects apparent 3.
• Another study published in Digestion reported the observations of 9 women who received omeprazole for severe reflux disease during different stages of pregnancy, with no severe side effects observed in any of the mothers or their newborns 4.
• A multicentre prospective controlled study published in Alimentary pharmacology & therapeutics found that the rate of major congenital anomalies did not differ between pregnant women exposed to omeprazole and a control group 5.
• A study published in the European journal of obstetrics, gynecology, and reproductive biology evaluated the magnitude of possible fetal risks involved in maternal use of omeprazole during pregnancy and found no clear-cut indication of ill effects 6.

Omeprazole Exposure and Fetal Risk

• The study published in Digestion found that follow-up of the children between 2 and 12 years showed normal development in all children 4.
• The study published in Alimentary pharmacology & therapeutics found that the rate of major congenital anomalies was 3.6% in the omeprazole-exposed group, compared to 3.8% in the control group 5.
• The study published in the European journal of obstetrics, gynecology, and reproductive biology found that the rate of congenital heart defects was slightly increased, but this may be random 6.

Breastfeeding and Omeprazole

• The study published in the Canadian journal of gastroenterology reported that peak omeprazole concentrations in breast milk were less than 7% of the peak serum concentration, indicating minimal secretion 3.
• A study published in Breastfeeding medicine found that the calculated daily infant dose of esomeprazole, the S-isomer of omeprazole, through breast milk was 0.003 mg/[kg·day], and the infant demonstrated normal developmental progress and no detectable drug-related adverse effects 7.