Exposure to anti-infective drugs during pregnancy and the risk of small-for-gestational-age newborns: a case-control study.

OBJECTIVE

To determine the association between anti-infective exposure during the last two trimesters of pregnancy and the risk of small-for-gestational-age (SGA) newborns.

DESIGN

Case-control study within the Québec Pregnancy Registry.

SETTING

Province of Québec, Canada.

SAMPLE

Analyses were performed on prospectively collected data of 63,338 pregnant women that met eligibility criteria for the study (8192 cases and 55,146 controls).

METHODS

Unconditional logistic regression models were used to quantify the association between exposure to anti-infective drugs and the risk of SGA.

MAIN OUTCOME MEASURES

A case of SGA was defined as a pregnancy resulting in a baby that weighs below the tenth percentile, adjusted for gestational age and gender, according to the Canadian gender-specific reference curves. A control was defined as a pregnancy resulting in a baby that weighs greater or equal to the tenth percentile, adjusted for gestational age and gender.

RESULTS

Exposure to all combined anti-infective drugs was not associated with the risk of SGA (OR 0.97; 95% CI 0.91-1.04). The use of sulfamethoxazole/trimethoprim was associated with SGA (OR 1.61; 95% CI 1.16-2.23), whereas the use of urinary anti-infective drugs decreased the risk (OR 0.80; 95% CI 0.65-0.97).

CONCLUSIONS

Exposure to sulfamethoxazole/trimethoprim during the last two trimesters of pregnancy was associated with SGA. Further research is needed to address the use of other therapeutic alternatives in the management of infections that predispose infants being born SGA in pregnant women with other risk factors for this condition.