The safety of nitrofurantoin during the first trimester of pregnancy: meta-analysis.

Asymptomatic bacteriuria is common during pregnancy and may adversely affect both the mother and her fetus. Nitrofurantoin (NF) has been long recognized as an effective agent in both nonpregnant and pregnant women suffering from urinary tract infections. This meta-analysis was conducted in order to evaluate the safety of NF ingested during early pregnancy. Of twenty-two studies, only four met the inclusion criteria and their analysis could not demonstrate any significant correlation between NF ingestion and fetal malformation. The pooled odds ratio was 1.29 with 95% confidence interval 0.25-6.57. Although the number and quality of the studies included are limited, we thought it important to present the existing data. More extensive controlled studies are urgently needed in order to increase the significance of our study.