Hypertensive disorders in pregnancy affect between 3 – 10% of pregnancies. Pre-eclampsia is the most severe of the disorders. It accounted for 2% of maternal mortalities in the UK between 2015 to 2017. Worldwide it is one of the leading causes of maternal mortality.
Types of Hypertension:
ESSENTIAL HYPERTENSION – High blood pressure (>140/80mmHg) prior to pregnancy that may require a change in medication.
GESTATIONAL HYPERTENSION – Raised blood pressure in pregnancy that occurs after 20 weeks gestation. Treated with anti-hypertensives and resolves 6 weeks after pregnancy.
PRE-ECLAMPSIA – Raised blood pressure in pregnancy that occurs after 20 weeks gestation associated with dysfunctional kidneys and a small baby. May lead to early delivery and the blood pressure resolves 6 weeks after delivery.
We will discuss management and delivery down below.
- At the initial antenatal appointment with the midwife, the risk factors above are assessed.
- Where there is a risk of pre-eclampsia, the guidance is to take up to 150mg of Aspirin daily until delivery to reduce the risk.
- Exercise and diet in pregnancy may be useful in reducing the risk.
- Women at risk should have more regular blood pressure checks towards the end of pregnancy (consider getting a BP machine)
- Pre-eclampsia is diagnosed with a blood pressure >140/90 and significant protein in the urine. The risk factors and red flag symptoms are explained in the images.
- Potential serious complications of pre-eclampsia are fluid in the lungs, bleed in the brain, liver failure, kidney failure, and death.
Treatment of Pre-Eclampsia
Labetalol is the 1st line treatment of choice. It is usually prescribed for up to three times a day. For a group of women it is not effective in reducing their blood pressure and therefore Nifedipine can replace it. Studies have shown this difference in response is not due to race but individual variation. Methyldopa is an older school medication that can also be used.
Once started on this medication, the blood pressure is measured regularly – at least once a week in the later part of the pregnancy. The aim is to keep the blood pressure below 150/90mmHg. If it exceeds this, then there is risk of a stroke or seizure and admission to the hospital is often needed to help keep it under control.
The cure for pre-eclampsia is delivering the placenta – so in cases where it is becoming difficult to manage the blood pressure, early delivery of the baby and placenta is needed. The baby’s growth is also monitored regularly as well as the heart beat as there is a high risk of having a small baby with pre-eclampsia.
In the post delivery period there is still a risk of seizure and strokes so it is important that the blood pressure is controlled with medication for up to 6 weeks after delivery.