The Control of Hypertension In Pregnancy Study pilot trial

Open Access
Publisher Website
Google Scholar
Abstract
Objective To determine whether ‘less tight’ (versus ‘tight’) control of nonsevere hypertension results in a difference in diastolic blood pressure (dBP) between groups. Design Randomised controlled trial (ISRCTN#57277508). Setting Seventeen obstetric centres in Canada, Australia, New Zealand, and UK. Population Inclusion: pregnant women, dBP 90–109 mmHg, pre‐existing/gestational hypertension; live fetus(es); and 20–33+6 weeks. Exclusion: systolic blood pressure ≥ 170 mmHg and proteinuria, contraindication, or major fetal anomaly. Methods Randomisation to less tight (target dBP, 100 mmHg) or tight (target dBP, 85 mmHg) blood pressure control. Main outcome measures Primary: mean dBP at 28, 32 and 36 weeks. Secondary: clinician compliance and women’s satisfaction. Other: serious perinatal and maternal complications. Results A total of 132 women were randomised to less tight (n= 66; seven had no study visit) or tight control (n= 66; one was lost to follow up; seven had no study visit). Mean dBP was significantly lower with tight control: −3.5 mmHg, 95% credible interval (−6.4, −0.6). Clinician compliance was 79% in both groups. Women were satisfied with their care. With less tight (versus tight) control, the rates of other treatments and outcomes were the following: post‐randomisation antenatal antihypertensive medication use: 46 (69.7%) versus 58 (89.2%), severe hypertension: 38 (57.6%) versus 26 (40.0%), proteinuria: 16 (24.2%) versus 20 (30.8%), serious maternal complications: 3 (4.6%) versus 2 (3.1%), preterm birth: 24 (36.4%) versus 26 (40.0%), birthweight: 2675 ± 858 versus 2501 ± 855 g, neonatal intensive care unit (NICU) admission: 15 (22.7%) versus 22 (34.4%), and serious perinatal complications: 9 (13.6%) versus 14 (21.5%). Conclusion The CHIPS pilot trial confirms the feasibility and importance of a large definitive trial to determine the effects of less tight control on serious perinatal and maternal complications.