The safety of nitrofurantoin during pregnancy
According to a large observational study conducted in Norway, the use of nitrofurantoin during pregnancy leads to a slight increase in the risk of birth defects.
It is known that the risk of developing jaundice in newborns increases when nitrofurans have been prescribed to women during the last 30 days of pregnancy. According to Norwegian scientists, other antimicrobial agents commonly used in the treatment of urinary tract infections (UTIs) do not adversely affect the course of pregnancy or the development of perinatal complications during pregnancy, including the first trimester.
A population cohort study was conducted in Norway, using information from the Norwegian National Fertility Register and the National Drug Administration database. The study population was 180,120 pregnant women in 2004-2008, of which 5,794 women received nitrofurantoin at different stages of pregnancy. The study compared pregnancy outcomes in the patient group studied with (1) a cohort that included 20,643 women (control group) who had been prescribed other antimicrobials for the treatment of urinary tract infections and with (2) 130,889 women who had not received antibacterial drugs at all during pregnancy..
Only 3.2% of the study population (5794 women) received nitrofurantoin during pregnancy, 1334 women (0.7%) in the first trimester and 979 patients (0.5%) in the last 4 weeks of pregnancy.
It has been found that women who received nitrofurantoin in the first trimester did not show an increased risk of giving birth to children with serious malformations, including those with cardiovascular malformations, compared to women who received beta-lactams during pregnancy (31 of 1,334 (2.4%) vs 162 of 5,800 (2.8%), odds ratio 0.79, confidence interval 95 % 0.51-1.23).
By evaluating the effects of nitrofurantoin during the last 4 weeks of pregnancy, the researchers found an increased risk of jaundice in newborns (103 out of 959 newborns (10.8%) vs 10,336 out of 127,507 newborns (8.1%) whose mothers did not receive antibiotics, odds ratio 1.31, 95% confidence interval 1.02-1.7).
The results of this study are not consistent with data from American scientists from the US Center for Disease Control and Prevention (CDC, Atlanta), published in 2009 in the journal Pediatrics. A CDC study found that nitrofurantoin was associated with birth defects, including vision, cardiovascular and cleft palate and lips.
The different results obtained in the two cohort studies may be due to differences in the study design and the sample size. For example, the results of American researchers were based on a retrospective survey of women on antibiotics taken during pregnancy. This method is associated with a slightly higher number of errors than the use of the medical appointment database, used by Norwegian researchers. In addition, an American study was conducted on a sample of smaller sizes.
Thus, according to Norwegian scientists, the results of their research are consistent with the data from most published work, which has not shown an increased risk of birth defects in a child when a woman takes nitrofurantoin during pregnancy.. At the same time, researchers emphasize the need for a woman to understand that the benefits of treating a urinary tract infection with antibiotics during pregnancy for the mother and baby should outweigh the possible risks.