Diabetes in Early Pregnancy Linked to Increased CAKUT Risk

Pregestational exposure to maternal diabetes—during the first 20 weeks of pregnancy—is associated with congenital anomalies of the kidney and urinary tract (CAKUT) in offspring, reports a study in the American Journal of Kidney Diseases.

The population-based study included 945 patients with CAKUT born in Manitoba, Canada, between 1996 and 2010. They were matched for gestational age, sex, and birth year to 4725 control children. The study focused on the association between CAKUT and timing of diabetes exposure: pregestational, including the first 20 weeks’ gestation; and gestational, beyond 20 weeks. The analysis was adjusted for a wide range of confounders, including size for gestational age as a surrogate for maternal glycemic control.

Pregestational exposure to maternal diabetes was significantly more common among infants with CAKUT: 4.1 percent, compared to 2.3 percent in the control group. There was no significant difference in gestational diabetes: 4.2 versus 3.3 percent, respectively.

In a multivariable model, the odds ratio for CAKUT in infants with pregestational diabetes exposure was 1.67. The estimated incidence of CAKUT in mothers with pregestational diabetes was 8.3 per 1000 live births, compared to 5 per 1000 in the general population. The presence of CAKUT was associated with both large and small size for gestational age: odds ratio 1.34 and 1.59, respectively.

Previous studies of the association between maternal diabetes and CAKUT have not examined potential differences by the timing of exposure. The new study finds a significant increase in CAKUT among infants with pregestational, but not gestational, exposure to diabetes.

The link with large size for gestational age suggests that poor glycemic control may increase risk. The authors discuss the need for optimal glycemic control during early pregnancy, with consideration of screening for renal anomalies [Dart AB, et al: Maternal diabetes mellitus and congenital anomalies of the kidney and urinary tract (CAKUT) in the child. Am J Kidney Dis 2015; 65:684–691].