Background

Although bacterial infections are frequent during pregnancy, the prescription of antibiotics to pregnant women represents a challenge for physicians, driven by the benefit–risk balance.

Objectives

To assess the extent of prenatal antibiotic exposure and its associated factors.

This study included pregnancies in the National Mother-Child EPI-MERES Register 2010–19 (built from the French Healthcare Data System) regardless of outcome. Antibiotic exposure was defined as having at least one antibiotic prescription filled during pregnancy. The prevalence of pregnancies exposed to antibiotics was estimated. Univariable Poisson regression with generalized estimating equations was used to compare the number of antibiotic prescriptions filled during pregnancy and the period after pregnancy with the period 1 year before pregnancy. Multivariable Poisson regression was used to investigate factors associated with antibiotic exposure during pregnancy.

Results

Among 9 769 764 pregnancies, 3 501 294 (35.8%) were exposed to antibiotics and amoxicillin was the most common. Compared with a similar period 1 year before pregnancy, the number of filled antibiotic prescriptions was lower during pregnancy [incidence rate ratio (IRR) 0.903 (95% CI 0.902–0.905)] and during the period 1 year after pregnancy [IRR 0.880 (95% CI 0.879–0.881)]. Region of residence, deprivation index, smoking-related conditions and chronic diseases (especially chronic respiratory diseases) were associated with antibiotic exposure during pregnancy.

Conclusions

Antibiotic prescriptions are filled less frequently during pregnancy than during the preceding year. This may be due to a more relevant benefit–risk assessment. Pregnant women living with social deprivation, those with smoking-related conditions and those with chronic diseases are more likely to fill antibiotic prescriptions.