Penicillin and several other antibacterial medications commonly taken by pregnant women do not appear to be associated with many birth defects, according to a new report.
However, the same report found that other antibiotics, such as sulfonamides and nitrofurantoins, may be associated with several severe birth defects and require additional scrutiny.
The report followed a study in which doctors analysed data from 13,155 women whose pregnancies were affected by one of more than 30 birth defects.
The information was collected by surveillance programmes in 10 US states as part of the National Birth Defects Prevention Study. The researchers compared antibacterial use before and during pregnancy between these women and 4,941 randomly selected control women who lived in the same geographical regions but whose babies did not have birth defects.
Antibacterial use among all women increased during pregnancy, peaking during the third month. A total of 3,863 mothers of children with birth defects (29.4 per cent) and 1,467 control mothers (29.7 per cent) used antibacterials sometime between three months before pregnancy and the end of pregnancy.
“Reassuringly, penicillins, erythromycins and cephalosporins, although used commonly by pregnant women, were not associated with many birth defects,” the authors stated.
Two defects were associated with erythromycins, one with penicillins, one with cephalosporins and one with quinolones.
However, two medications – sulfonamides and nitrofurantoins – were associated with several birth defects, suggesting that additional research is needed before they can be safely prescribed to pregnant women.
“Determining the causes of birth defects is problematic,” the authors added.
“A single defect can have multiple causes, or multiple seemingly unrelated defects may have a common cause. This study could not determine the safety of drugs during pregnancy, but the lack of widespread increased risk associated with many classes of antibacterials used during pregnancy should be reassuring.”
Archives of Pediatrics and Adolescent Medicine