Background: Antibiotics are the most widely used medication on prescription in pregnancy. It is therefore important to investigate whether antibiotic use in pregnancy can harm the foetus. During the last decade the availability of data from national registries has made it possible to conduct large-scale epidemiological studies. In this article we aimed to review recent studies on the risk of congenital anomalies and miscarriage resulting from the use of antibiotics in pregnancy.
Method: A literature search was conducted in MedLine, Embase and PubMed for the period 1 December 2005-1 December 2015. We identified 1,316 articles, of which 23 met the inclusion criteria.
Results: Recent epidemiological studies have focused on investigating the risks of malformations and pyloric stenosis after exposure to macrolides, nitrofurantoin, penicillins and trimethoprim-sulphamethoxazole. In nine of ten studies that included in total more than 38,000 patients exposed to macrolides, and two studies with more than 7,000 exposed to nitrofurantoin, no significantly increased risk of malformations was discovered. There are some contradictory findings for certain groups of antibiotics with regard to the risk of miscarriage, heart defects and pyloric stenosis.
Interpretation: Recent studies indicate that erythromycin and nitrofurantoin can be used as second-line drugs in the first trimester. The results from recent studies concur with the recommendations for pregnant women in national guidelines regarding antibiotic use in the primary health service.