Omeprazole is Safe During Pregnancy
Omeprazole can be used safely during pregnancy when clinically indicated, with extensive human data showing no increased risk of major congenital malformations. 1
Evidence Supporting Safety
FDA Drug Label Data
The FDA label for omeprazole confirms that available epidemiologic data fail to demonstrate an increased risk of major congenital malformations or other adverse pregnancy outcomes with first trimester omeprazole use. 1 Multiple large-scale studies support this conclusion:
Swedish Medical Birth Registry study (1995-1999) followed 955 infants exposed to omeprazole during pregnancy, with 824 exposed during the first trimester. The number of infants with malformations, low birth weight, low Apgar scores, or hospitalizations was similar to the general population. 1
Danish nationwide cohort study (1996-2009) included 1,800 live births with first trimester omeprazole exposure. The overall birth defect rate was 2.9% in the omeprazole group compared to 2.6% in unexposed mothers—essentially equivalent to background rates. 1
Retrospective cohort study of 134 pregnant women exposed to omeprazole in the first trimester showed a malformation rate of 3.6%, comparable to unexposed controls at 4.1%. 1
Clinical Research Evidence
A prospective controlled study from the European Network of Teratology Information Services followed 295 pregnancies exposed to omeprazole (233 in first trimester) and found the major congenital anomaly rate was 3.6%, identical to the control group rate of 3.8%. 2 This multicenter study provides robust evidence that omeprazole does not represent a major teratogenic risk. 2
Long-term follow-up data from a case series showed normal development in all children followed between 2 and 12 years after in utero omeprazole exposure. 3
Clinical Application
When to Use Omeprazole
Omeprazole should be used when:
- Gastroesophageal reflux disease is refractory to safer first-line agents (antacids, sucralfate, H2-receptor antagonists like ranitidine) 4
- Severe reflux symptoms significantly impact maternal quality of life 3
- Peptic ulcer disease requires treatment during pregnancy 3
- Bleeding from upper GI pathology occurs 3
Timing Considerations
While omeprazole can be used throughout pregnancy, the evidence is strongest for use after the first trimester. 1 However, the large epidemiologic studies showing safety included substantial first trimester exposures, so continuation from preconception or initiation in the first trimester is acceptable when clinically necessary. 1
Important Caveat
One older Turkish guideline from 2017 suggested avoiding omeprazole specifically and preferring other PPIs after the first trimester. 4 However, this recommendation contradicts the more robust FDA data and large epidemiologic studies, and appears to be an outlier. The preponderance of high-quality evidence, including the FDA drug label and multiple large population studies, supports omeprazole safety throughout pregnancy. 1, 2
Dosing
Standard adult dosing should be used during pregnancy, as there is no evidence requiring dose adjustment. 3 The typical dose ranges from 20-40 mg daily depending on indication. 3, 5
Breastfeeding Considerations
Omeprazole is minimally secreted into breast milk, with peak concentrations less than 7% of maternal serum levels. 5 Esomeprazole (the S-isomer of omeprazole) showed similarly low transfer, with calculated daily infant dose of only 0.003 mg/kg/day through breast milk. 6 This minimal exposure makes omeprazole compatible with breastfeeding. 5, 6