The prevalence of all pregnancies with some form of hypertension can be up to 10%, with the rates of diagnosis varying according to the country and population studied and the criteria used to establish the diagnosis.

Prepregnancy obesity and excessive gestational weight gain (GWG) of all body mass index (BMI) categories have been associated with maternal hypertensive disorders and linked to macrosomia (>4000 g) and low birthweight (<2500 g). No large randomized controlled trial with high adherence to an exercise program has examined pregnancy-induced hypertension and these associated issues.

We investigated whether women adherent (≥80% attendance) to an exercise program initiated early showed a reduction in pregnancy-induced hypertension and excessive GWG in all prepregnancy BMI categories, and determined if maternal exercise protected against macrosomia and low birthweight.Maternal exercise may be a preventative tool for hypertension and excessive GWG, and may control offspring size at birth while reducing comorbidities related to chronic disease risk.

Source: http://www.ajog.org/article/S0002-9378(15)02479-5/abstract