Genitourinary infections (GUIs) are commonly encountered among sexually active women. The association between the risk of birth defects and GUIs is not clearly understood. A study published in Birth Defects Research used data from the National Birth Defects Prevention Study to assess self-reported maternal GUIs in the month before through the third month of pregnancy (periconception) from 29,316 birth defect cases and 11,545 unaffected controls. Nearly 10% (n = 2,972) of case and 9% (n = 1,014) of control mothers reported a periconceptional GUI. A GUI was found to be significantly associated with 11 of the 52 birth defects examined (ORs ranging from 1.19 to 2.26): encephalocele, cataracts, cleft lip, esophageal atresia, duodenal atresia/stenosis, small intestinal atresia/stenosis, colonic atresia/stenosis, transverse limb deficiency, conoventricular septal defect, atrioventricular septal defect, and secundum atrial septal defect. Periconceptional UTI was significantly associated with nine birth defects (ORs from 1.21 to 2.48), and periconceptional STI had a significant association with four birth defects (ORs ranging from 1.63 to 3.72). The study suggested that GUIs during the periconceptional period may be associated with increased risk for specific birth defects.