# Factors associated with antibiotic use during pregnancy in Sweden: a population-based cohort study

## TL;DR

This study identifies factors like pre-existing health conditions and young maternal age that increase antibiotic use during pregnancy in Sweden.

## Contribution

The study provides new insights into individual-level predictors of antibiotic use during pregnancy using nationwide data.

## Key findings

- Preconception drug use, chronic renal disease, and low maternal age were most strongly linked to antibiotic use.
- Chronic conditions and immunodeficiency were associated with broader and more frequent antibiotic use.
- Younger women and those with pre-existing health issues may need targeted infection prevention strategies.

## Abstract

Understanding determinants of antibiotic use during pregnancy is crucial for optimizing their utilization in clinical practice. We aimed to investigate which individual-level factors are associated with antibiotic use among pregnant women.

Population-based cohort study using linked data from the Swedish national health and population registers spanning from 2006 to 2019. Sociodemographic characteristics, medical and obstetric history, lifestyle and healthcare utilization were investigated as independent variables. Any systemic antibiotic use during pregnancy, the primary outcome, was determined from filled prescriptions, with broad-spectrum antibiotics and multiple courses of antibiotics as secondary outcomes. Multiple logistic regression was used to estimate odds ratios (ORs), including all independent variables in the model.

Among 20 variables associated with any systemic antibiotic use during pregnancy, preconception prescription drug use (OR 1.93 [95% CI 1.87–1.98] for > 4 vs. 0–1 unique therapeutic subgroups), chronic renal disease (1.82 [1.73–1.93]) and low maternal age (1.67 [1.61–1.74] for ages < 20 vs. 30–34 years) had the highest odds. Chronic renal disease, immunodeficiency disorders and preconception drug use (> 4 vs. 0–1 therapeutic subgroups) had the highest odds of broad-spectrum antibiotic use and use of multiple antibiotic courses.

Pre-existing morbidities and low maternal age were most strongly associated with antibiotic use during pregnancy, suggesting a needs-based approach in prescribing. Proactive management of morbidities and infection prevention strategies, particularly targeting young women of reproductive age, could potentially reduce the need for antibiotic treatment in prenatal care.

The online version contains supplementary material available at 10.1186/s12884-025-07736-4.