Clinical characteristics and sequelae of intrapartum hypertension - a retrospective cohort study

Background In a significant proportion of pregnant women, elevated blood pressure may first present during the intrapartum period. This phenomenon, intrapartum hypertension, is often overlooked as blood pressure during delivery is attributed to labour pain, analgesic agents and haemodynamic changes. Thus the true prevalence and clinical significance of intrapartum hypertension remains unknown. This study sought to define the prevalence of intrapartum hypertension in previously normotensive women, identify associated clinical characteristics, and its impact on maternal and fetal outcomes. Methods In this single-center retrospective cohort study, all available partograms were reviewed over a 1-month period at an outer metropolitan hospital in Sydney (Campbelltown Hospital). Women with diagnosed hypertensive disorders of pregnancy during the incident pregnancy were excluded. A total of 229 deliveries were included in the final analysis. Intrapatum hypertension (IH) was defined as two or more systolic blood pressure (SBP)> 140 mmHg or diastolic blood pressure (DBP)> 90 mmHg during the intrapartum. Demographic data at the time of the first antenatal visit for the incident pregnancy as well as final maternal outcomes (intrapartum and post-partum) and fetal outcomes were collected. Statistical analyses were carried out using SPSSv27 with adjustments for baseline variables. Results Amongst 229 deliveries, 32 women (14%) had intrapartum hypertension. Older maternal age (p = 0.02), higher body mass index (p < 0.01) and higher diastolic blood pressure at the first antenatal visit (p = 0.03) were associated with intrapartum hypertension. A longer second stage of labour (p = 0.03), intrapartum non-steroidal anti-inflammatory medications (p < 0.01) and epidural anaesthesia (p = 0.03) were associated with intrapartum hypertension, while IV syntocin for labour induction was not. Women with intrapartum hypertension had a longer inpatient admission following delivery (p < 0.01), and elevated postpartum BP (p = 0.02) with discharge on antihypertensive medications (p < 0.01). Intrapartum hypertension was not associated with poor fetal outcomes, though subgroup analyses showed that women who had at least a single elevated blood pressure reading during the intrapartum experienced poorer fetal outcomes. Conclusion In previously normotensive women, 14% developed intrapartum hypertension during delivery. This was associated with postpartum hypertension, longer maternal admission and discharge with antihypertensive medications. There was no difference in fetal outcomes.