Maternal and perinatal outcomes according to blood pressure levels for prehypertension: A review and meta-analysis

Aim: This study aimed to examine whether blood pressure >= 130/80 mmHg is an appropriate reference value for hypertension in pregnant women by conducting a meta-analysis of studies reporting maternal/perinatal outcomes according to blood pressure levels at < 20 weeks of gestation. Methods: The meta-analysis of studies identified through PubMed/MEDLINE and Ichushi-Web searches was conducted to evaluate the incidence of preeclampsia, gestational hypertension, hypertensive disorders of pregnancy, preterm birth, and small-for-gestational-age birth. Results: The meta-analysis of 12 prospective and retrospective cohort studies revealed that the risks of preeclampsia, gestational hypertension, and hypertensive disorders in pregnancy were higher in women with blood pressure >= 120/80 mmHg, particularly >= 130/80 mmHg, relative to < 120/80 mmHg. The risk of preterm birth was higher in women with blood pressure >= 120/80 mmHg, and significantly higher in those with blood pressure >= 140/90 mmHg, relative to < 120/80 mmHg. The risk of small-for-gestational-age birth did not differ significantly by blood pressure status. Conclusions: Blood pressure >= 120/80 mmHg, particularly >= 130/80 mmHg, is associated with increased maternal and perinatal risks. We propose new blood pressure categories as normal (< 120/80), high normal (120-129/<80), and elevated (130-139/80-89), although further studies will be needed to set >= 130/80 mmHg as a new reference for hypertension in pregnant women.