Overweight from childhood to adulthood ups risks of hypertensive disorders in pregnancy

Body mass index (BMI) values that are above average and the development of overweight from childhood to adulthood are risk factors for gestational hypertension and pre-eclampsia, but normalizing BMI from childhood to conception reduces such risks, according to a study.

“Thus, interventions aiming at normalizing BMI in girls with high values may be warranted to help prevent these obstetric diseases,” the investigators said.

Using the Copenhagen School Health Records Register, the investigators examined 49,600 women born between 1940 and 1996 with height and weight measurements at 7 years and/or 13 years who had their first singleton birth between ages 18 and 45 years. They also identified women with gestational hypertension (n=496) and pre-eclampsia (n=1,804) from the International Classification of Disease codes in the Danish National Patient Register.

Adult overweight, including obesity, was defined as a BMI ≥25 kg/m². Log-linear binomial regression was used to estimate risk ratios (RRs) and 95 percent confidence intervals (CIs).

At 13 years, above-average BMI increase (z score >0, or the 42nd percentile of the CDC BMI reference) resulted in an RR of 1.66 (95 percent CI, 1.42–1.94) for gestational hypertension and 1.57 (95 percent CI, 1.46–1.70) for pre-eclampsia per BMI z score.

A subset analysis of 13,160 revealed that development of overweight from childhood to adulthood and being overweight at both ages correlated with higher risks of the outcomes compared to a normal BMI at both ages.

Moreover, such risks did not increase in women whose BMI normalized from childhood to adulthood (gestational hypertension: RR, 2.04, 95 percent CI, 0.93–4.47; pre-eclampsia: HR, 1.11, 95 percent CI, 0.63–1.93).