Observational studies in patients with
mild chronic hypertension demonstrate that the risk of pregnancies are: preeclampsia (l0-25%), abruptio (0.7-l.0%), premature birth less than 37 weeks (12-34%) and intrauterine fetal growth (8-16%). The risk increases in severe chronic hypertension during the first trimester since the risk of experiencing preeclampsia increases up to 50%.