Post-Partum Hypertension

Working in obstetrics and gynaecology, a common job is to review women after delivery to ensure that they are fit for discharge from hospital to the community. It is not uncommon for patients to be found to be hypertensive following delivery. In the BMJ this week there is a clinical review article on post-partum hypertension which I'll aim to summarise here, mainly focusing on raised BP <6 p="" post-partum.="" weeks="">

The most common cause for hypertension after delivery is due to pregnancy induced hypertension or pre-eclampsia which occurred prior to delivery. Hypertension is common in pregnancy and affects 6-10% of pregnancies. There are certain anti-hypertensives which have been shown to be safe in women who are breast-feeding, including labetalol and enalapril. Women who continue to have raised BP and proteinuria 6 weeks after delivery need referral to a specialist for further investigation. It's important to remind women that if they have had PIH then they are at increased risk of high BP in future pregnancies, particularly if they have had pre-eclampsia. 

Pre-eclampsia, eclampsia or HELLP (haemolysis, elevated liver enzymes, low platelets) may present for the first time in the post-natal period. BP usually falls immediately after delivery but then steadily rises and peaks at day 3-6 post-partum as a physiological event. Transient hypertension may occur post-partum in normal pregnancies for reasons such as pain, fluid administration and change in vascular tone resulting in fluid shift into the intra-vascular space. Automated BP cuffs may underestimate BP and readings should be confirmed manually. New onset of pre-eclampsia would involve the patient complaining of symptoms such as headaches, epigastric pain, visual changes or possibly seizures.

Several studies have reported that BP should be expected to normalise within 3-7 days after delivery although this will clearly increase if there has been pre-existing hypertension. NICE recommend checking BP 6 hours after delivery and again at day 5 to identify women with late presentation of pre-eclampsia. Measurement of proteinuria immediately post-partum is not recommended due to the presence of lochia. Any patients who have been discharged to the community and are found to have BP >160/>110 will need re-referred to hospital for assessment and treatment. NICE have created guidelines and a useful flowchart for the safe management of out-patients with hypertension during the first 6 weeks post-partum. After discharge from hospital, BP must be checked at least every other day by the community midwife until targets are met. Data on anti-hypertensives used post-partum is extremely limited and mostly based on expert consensus but treatments should be chosen carefully to reduce risk of transmission to the baby during breastfeeding.