PI: Armstrong, Don MD

According to population-based data, 7-9% of pregnancies are complicated by hypertension [i.e., diastolic blood pressure (dBP) = 90mmHg](1;2). Approximately 1% of pregnancies are complicated by pre-existing hypertension, 5-6% by gestational hypertension without proteinuria (half present preterm), and 2% by pre-eclampsia (usually defined as gestational hypertension with proteinuria)(3). Pre-existing hypertension presents before pregnancy or before 20 weeks gestation, and may be primary or secondary (e.g., to renal disease)(4). Gestational hypertension presents at = 20 weeks (with/without proteinuria)(5). Pre-existing or gestational hypertension may be non-severe or severe, usually defined as a BP of =160-170/110mmHg. For the planned CHIPS Trial, our focus is women with hypertension that presents at <34 weeks, and is non-severe, non-proteinuric, and either pre-existing (1% of all pregnancies) or gestational (2-3% of all pregnancies). At present, it is unclear how best to manage their non-severe, non-proteinuric hypertension. Current practice approaches include both ‘less tight’ control (allowing BP to be higher than normal) and ‘tight’ control (normalising BP). The effects of each approach on perinatal and maternal outcomes needs to be determined. As emphasized by the apparent perinatal advantages of ‘less tight’ control in the CHIPS Pilot Trial, a definitive RCT, such as the proposed CHIPS Trial, now needs to be conducted.

According to population-based data, 7-9% of pregnancies are complicated by hypertension [i.e., diastolic blood pressure (dBP) = 90mmHg](1;2). Approximately 1% of pregnancies are complicated by pre-existing hypertension, 5-6% by gestational hypertension without proteinuria (half present preterm), and 2% by pre-eclampsia (usually defined as gestational hypertension with proteinuria)(3). Pre-existing hypertension presents before pregnancy or before 20 weeks gestation, and may be primary or secondary (e.g., to renal disease)(4). Gestational hypertension presents at = 20 weeks (with/without proteinuria)(5). Pre-existing or gestational hypertension may be non-severe or severe, usually defined as a BP of =160-170/110mmHg. For the planned CHIPS Trial, our focus is women with hypertension that presents at <34 weeks, and is non-severe, non-proteinuric, and either pre-existing (1% of all pregnancies) or gestational (2-3% of all pregnancies). At present, it is unclear how best to manage their non-severe, non-proteinuric hypertension. Current practice approaches include both ‘less tight’ control (allowing BP to be higher than normal) and ‘tight’ control (normalising BP). The effects of each approach on perinatal and maternal outcomes needs to be determined. As emphasized by the apparent perinatal advantages of ‘less tight’ control in the CHIPS Pilot Trial, a definitive RCT, such as the proposed CHIPS Trial, now needs to be conducted.