Severe hypertension, preeclampsia and small for gestational age in women with chronic hypertension diagnosed before and during pregnancy

Objectives: To compare rates of severe hypertension (SH), preeclampsia (PE) birth of small for gestational age (SGA) neonates between women with chronic hypertension (CH) diagnosed during the first trimester of pregnancy and those with pre-pregnancy CH. Study design: Prospective cohort study of women with CH and singleton pregnancies referred to an Antenatal Hypertension Clinic at 8-14 weeks' gestation. At presentation the patients were subdivided into four groups based on blood pressure (BP) control. Group 1 included women without a preceding history of CH presenting with BP of >= 140/90 mmHg (n = 86). Groups 2-4 had pre-pregnancy CH; in group 2 the BP was < 140/90 mmHg without antihypertensive medication (n = 200), in group 3 the BP was < 140/90 mmHg with anti-hypertensive medication (n = 231) and in group 4 the BP was >= 140/90 mmHg despite antihypertensive medication (n = 173). Main outcome measures: PE, SH (BP >= 160/110 mmHg), SGA (birthweight < 10th percentile). Results: In group 1, the rate of SH (15.1%), was similar to that in group 2 (10.5%) and group 3 (23.8%) but significantly lower than in group 4 (52.6%). In group 1, the rate of PE (12.8%) and SGA < 10th centile (18.6%) were similar to those in group 2 (16.5% and 21.0%) and significantly lower than in group 3 (26.0 and 30.7%) and group 4 (26.6% and 31.8). Conclusion: In women diagnosed with CH in the first trimester of pregnancy, the rates of SH, PE and SGA are similar to those with pre-pregnancy CH who present with BP below 140/90 without the need for anti-hypertensive medication.