First trimester maternal blood rheology and pregnancy induced hypertension

Abstract

This study evaluates the relationship between the first trimester assessment of maternal rheology and the subsequent development of pregnancy induced hypertension. This is a prospective observational study based in the Glasgow Royal Maternity Hospital, Scotland. From an original population of 744 consecutive antenatal attendees a total of 579 women were booked at less than 14 weeks' gestation. The main study group is a further subset comprising 251 primigravid women booking with a singleton pregnancy without essential hypertension. Previously published data from a group of non-pregnant women of similar age drawn from the same local community was used for external comparison. Blood samples were collected at the booking visit, from which fibrinogen, red cell aggregation, haematocrit and plasma, whole blood, relative and corrected viscosities were recorded. Information was obtained from the case notes in retrospect starting approximately 1 year after the first patients had first been recruited into the trial. The overall outcome of the pregnancies was noted with particular reference to pregnancy induced hypertension (PIH), birth weight, antepartum haemorrhage, pre-term labour, perinatal death, condition at delivery and neonatal complication. Our results show PIH is associated with a significantly raised mean blood viscosity and fibrinogen at time of booking. All significance disappears after adjustment for smoking, diastolic blood pressure and age. Viscosity is, however, only marginally non-significant (p=0.07). In conclusion, blood rheology, in particular blood viscosity and fibrinogen, may play a predictive role in the development of pregnancy-induced hypertension. When combined with measurement of smoking and diastolic blood pressure at booking, these measurements could be used to calculate a risk score for the development of PIH, allowing targeting of antenatal care. Further data is required.