Is Prilosec safe during pregnancy?

What does the evidence say about Prilosec during pregnancy?

1. Available information does not point to a higher chance of birth defects when omeprazole is used in pregnancy, against a background chance of about 3 percent in any pregnancy. 1
2. A pooled analysis of 534 omeprazole-exposed pregnancies found a relative risk of 1.05 for malformations (95% CI 0.59 to 1.85), meaning no measurable difference from unexposed pregnancies. 2
3. A 2023 study of 2,696,216 pregnancies, 40,540 of them exposed to a proton pump inhibitor in the first trimester, concluded these drugs are unlikely to be a major teratogen; the sibling comparison gave an odds ratio of 1.05 (95% CI 0.91 to 1.22). 3
4. Omeprazole shuts off the stomach's acid pump at the last step of acid production, with effects starting within an hour of a dose and peaking around two hours. 4
5. Proton pump inhibitors work best taken before food, since the pumps they act on switch on during a meal, and the full effect takes a few days to build. 5

Is Prilosec safe in each trimester?

• First trimester. Reflux is less common this early, so most first-trimester questions come from people who were already taking omeprazole before they conceived. Bring it up at your first visit rather than quitting on your own. Large registry studies have looked specifically at first-trimester exposure and found malformation rates in line with the background rate.
• Second trimester. Heartburn usually starts climbing now as the uterus pushes upward and the valve at the top of the stomach loosens. Most clinicians work up a ladder first: smaller meals, an antacid after eating, then famotidine on a schedule. Omeprazole tends to enter the picture when those steps stop holding.
• Third trimester. Reflux often peaks in the last weeks, and daily omeprazole is common at this stage. It builds to full effect over a few days, so it works better on a set schedule than as a rescue dose after a bad night. Ask your provider how long to stay on it once the baby arrives.