Do antibiotics increase risk of major congenital malformations?

August 15, 2017

A study looks at the suspected association between certain antibiotics and the risk of major congenital malformations. Plus: A look at the impact that diet may have on the rate of cesareans.

According to results of a recent Canadian study published in TheBritish Journal of Pharmacology, certain antibiotics may increase the risk of major congenital malformations (MCMs).

Researchers used the Quebec pregnancy cohort, which included data from 1998 to 2008 and included a total of 139,938 live singleton infants whose mothers had been covered by the Régie de l'assurance maladie du Québec drug plans for at least 12 months before and during pregnancy. Exposure to antibiotics was assessed in the first trimester and MCMs were identified over the course of the first year of an infant’s life.

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Following adjustment for potential confounders, exposure to clindamycin was linked with an increased risk of MCMs (adjusted odds ratio [aOR] 1.34, 95% confidence interval [CI], 1.02-1.77, 60 exposed cases), musculoskeletal system malformations (aOR 1.67, 95%CI, 1.12-2.48, 29 exposed cases), and atrial/ventricular septal defects (aOR 1.81, 95%CI, 1.04-3.16, 13 exposed cases).

Exposure to doxycycline increased the risk of circulatory system malformations, cardiac malformations, and atrial/ventricular septal defects (aOR 2.38, 95%CI ,1.21-4.67, 9 exposed cases; aOR 2.46, 95%CI, 1.21-4.99, 8 exposed cases; aOR 3.19, 95%CI, 1.57-6.48, 8 exposed cases, respectively). Associations were also seen with quinolone (1 defect), ofloxacin (1 defect), erythromycin (1 defect), phenoxymethylpenicillin (1 defect), macrolide (1 defect), and moxifloxacin (1 defect). No association was seen with nitrofurantoin, amoxicillin, or cephalosporins. When penicillins were used as a comparator group, similar results were seen.

The authors concluded that in utero exposure to certain antibiotics, such as clindamycin, doxycycline, quinolones, macrolides and phenoxymethylpenicillin, was linked to organ-specific malformations.

NEXT: Impact of diet and activity on reducing cesarean rate


Impact of diet and activity on reducing cesarean rate

A recent meta-analysis published in The BMJ offers hope for reducing the risk of cesarean by lowering gestational weight gain and risk of development of diabetes over the course of pregnancy.

For the study, researchers analyzed individual participant data (IPD) from 36 randomized trials, covering a total of 12,526 women. Studies were eligible for inclusion if they assessed diet- and physical activity-based interactions in pregnancy.

The authors found that less weight gain occurred in the intervention group than the control group (mean difference −0.70 kg, 95% confidence interval [CI] −0.92 to −0.48 kg, I2=14.1%; 33 studies, 9320 women). Reductions in offspring (odds ratio [OR] 0.94, 0.83 to 1.08, I2=0%; 18 studies, 7981 women) and maternal (OR 0.90, 95% CI 0.79 to 1.03, I2=26.7%; 24 studies, 8852 women) composite outcomes were found to not be statistically significant.

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Strong evidence showed that interventions reduced the risk of cesarean (OR 0.91, 0.83 to 0.99, I2=0%; 32 studies, 11 410 women), but not for other individual complications. When the IPD were combined with data from studies that did not provide IPD, the effect was similar, with stronger evidence for the benefit for gestational diabetes (OR 0.76, 0.65 to 0.89, I2=36.8%; 59 studies, 16,885 women). The researchers said the benefits of diet and exercise were consistent regardless of body mass index, age, parity, ethnicity, or pre-existing medical conditions and also remained when they excluded studies at high risk of bias.

The authors concluded that diet and physical activity intervention in pregnancy reduce gestational weight gain and lower the odds of cesarean.