Prediction and prognosis of hypertension in pregnancy

Abstract

Hypertensive disorders represent the most significant complication of pregnancy and affect about 10% of all pregnancies. Early referral for specialist care for those who are at risk might translate into improved management of these women, while the possibility to identify women at very low risk for developing hypertensive disease, might be of great benefit to the organisation and planning of antenatal care, by redirecting the burden of frequent visits for all women to those who may really benefit. We developed and validated a prediction model for the development of hypertension in healthy nulliparous women. The model, based on three simple clinical variables, accurately identifies women at very low and very high risk of becoming hypertensive before 36 weeks of gestation. Application of this prediction model in a midwifery care setting may lead to a reduction in frequency of antenatal visits for low-risk and increased surveillance for high-risk women. Furthermore, we developed a model for early-onset pre-eclampsia (PE) in apparently healthy women, and a model for recurrent early-onset PE, both based on combinations of easy to measure clinical and biochemical risk factors, to be used in a preconceptional care setting. When confirmed in recent cohorts, these models may facilitate prepregnancy risk stratification, enabling selection of high-risk women eligible for further testing and/or intensive surveillance in pregnancy, while low-risk women may be monitored safely by routine antenatal care. Hypertensive disorders of pregnancy do not only pose the mother at risk of adverse pregnancy outcomes, but also imply an increased risk later in life. We studied apparently healthy primiparous women with a history of early-onset PE and found high rates of major independent risk factors for cardiovascular disease (CVD) already present within the first years after delivery, when compared to a population based same-age reference group. Although the estimated absolute 10-year CVD risk is low at the age of 30 years, a considerable proportion of these women are expected to develop a high CVD risk with increasing age, for which risk factor management is indicated. The primary care physician may play an important role in the follow-up of these women after pregnancy, in terms of early identification of high risk subjects and early initiation of treatment of hypertension and other risk factors for CVD. We investigated the extent of cardiovascular risk factor management in general practice in these women and found that blood pressure was more often checked after pregnancy in women who experienced PE than in controls, but in half of the cases only within 3 months after delivery with no further follow-up visit. A check for glucose and cholesterol levels was rare, and equally frequent in PE and control women. 20% of the previously normotensive women in the PE group had hypertension at one or more occasions after three months post partum versus none in the control group. Despite the evidence of increased risk of future cardiovascular disease in women with a history of PE, follow-up of these women seems to be insufficient and undeveloped in primary care in the Netherlands.