The prevalence of pre-eclampsia and obstetric outcome in pregnancies of normotensive and hypertensive women attending a hospital specialist clinic

To study the prevalence of pre-eclampsia (PE) and other obstetric outcomes (growth restriction and fetal mortality) in pregnancies of normotensive and hypertensive women attending an antenatal hypertension clinic, we studied a cohort of 372 pregnancies from 267 women. The prevalence of PE in the groups of pregnancies of normotensive and chronic hypertensive women was 11.9% (19/159 cases) and 16.0% (34/213 cases) respectively (chi 2 = 1.2, p = 0.27). There were no significant differences in respect of ethnicity, being primi- or multigravida and smoking status or age. Treatment with antihypertensive drugs during pregnancy did not decrease the prevalence of PE. In pregnancies with hypertensive complications (with or without PE) there was a trend towards higher rates of pre-term delivery (<37 weeks), caesarean section, small for gestational age babies, stillbirth and lower baby birth weight and ponderal index values. Pregnancies in women with uncomplicated hypertension had an increased risk for emergency caesarean section, pre-term delivery (<37 weeks), birth weight <2500 g and stillbirth (relative risks [with confidence intervals] 2.5 [1.9-3.2], 2.3 [1.8-2.9], 3.1 [2.5-3.7] and 5.5 [2.6-11.9] respectively) compared with the general hospital obstetric population. After classification according to the type of hypertensive syndrome, a progressively higher risk for fetal growth restriction and adverse perinatal outcome was shown in the hypertensive and pre-eclamptic groups. In chronic hypertension, this was irrespective of superimposed pre-eclampsia or antihypertensive therapy. The high prevalence of PE in chronic hypertensive women (16.0%) was not statistically significant to that of normotensive women (11.9%), reflecting the referral selection of 'high risk' normotensive women to our clinic.