Transient gestational hypertension: Not always a benign event

Pregnancy outcome in women with transient gestational hypertension (TGH);defined as de novo blood pressure elevation after 20weeks gestation that normalizes by subsequent evaluation in a Day Assessment Unit.

Retrospective cohort analysis of hypertensive pregnancies between 2003 and 2008.

Final hypertensive delivery diagnosis and composites of adverse maternal and fetal outcome.

Overall 1417 women were referred; 890 met criteria; 41% (65% of study population) had TGH. Twenty percent with TGH developed gestational hypertension and 19% preeclampsia. Women with TGH who developed preeclampsia had similar composite adverse maternal outcomes to other preeclamptic women (51% vs. 63%; p=0.24) but fewer adverse fetal outcomes (50% vs. 71%; p<0.01) due to less prematurity (30% vs. 45%; p=0.02) and small for gestational age babies (33% vs. 51%; p=0.02). Within the TGH population;developing gestational hypertension or preeclampsia was associated with referral at gestation <33weeks (RRR 2.8; p<0.01);initial average systolic blood pressure 130-139mmHg (RRR 2.1; p<0.01) and initial average diastolic blood pressure 80-89mmHg (RRR 3.2; p<0.01).

TGH after 20weeks is common in pregnancy. Although initial assessment implies low risk;the risk of progression to gestational hypertension or preeclampsia is substantial and warrants appropriate clinical surveillance.