High Blood Pressure During Pregnancy

Prepared by Dr. Hon Sook Kit,

Consultant Obstetrician and Gynaecologist,

Gleneagles Medini Johor

Non-communicable diseases are on the rise in Malaysia, with hypertension among those leading the way in terms of prevalence. According to the National Health and Morbidity Survey 2015, high blood pressure affects 30.3 of all adults aged 18 years and above, or one in three Malaysians.

Of those diagnosed with the condition, hypertension was prevalent in 14% of women compared to 12.2% of men. While there is no direct link between the disease and gender, pregnancy is a known risk factor.

Blood pressure is one of the vital signs your obstetrician looks out for during an antenatal check-up. The reading is given as two numbers: the first is the pressure when the heart contracts and the second is the pressure when it relaxes. High blood pressure can be confirmed when the first number is 140 or greater or when the bottom number is 90 or greater over a period of weeks.

The condition puts extra strain on the heart and kidneys. Left unchecked, this can lead to heart and kidney diseases in addition to stroke.

While hypertension during pregnancy is a concern, by approximately managing blood pressure, safe pregnancy and healthy baby can be ensured.

Types of hypertension in pregnancy

There are several kinds of hypertension that can arise when you are expecting:

• Gestational hypertension only occurs during pregnancy and usually develops after the first 20 weeks. A warning sign of this condition is the presence of protein in urine or changes in liver function. Though this form of high blood pressure is typically temporary, some women may develop chronic hypertension later in life and could be at risk for more serious complications in pregnancy such as preeclampsia. Women who are overweight or obese prior to pregnancy may lower their chances of having this condition by getting to a healthy weight.
• Chronic hypertension affects women who either had high blood pressure prior to pregnancy or having developed it within the first 20 weeks. It is important to disclose medication intake to your obstetrician so that they can determine its safety, advise lower dosage, or recommend other options. Certain medicines, namely ACE inhibitors and angiotensin receptor blockers, can harm the foetus. It is possible for women to further develop chronic hypertension with superimposed preeclampsia. Those with this condition may experience worsening high blood pressure and abnormal amounts of protein in their urine, which can lead to changes in liver function and problems with the kidneys.
• Preeclampsia is a severe medical condition that usually occurs in the third trimester, and in rare cases, after delivery. It is associated with signs of damage to other organs, including the brain, blood, kidneys, and liver. Left untreated, preeclampsia can lead to life-threatening complications for mother and baby. Among them are eclampsia, which causes seizures and possibly coma, as well as the fatal HELLP syndrome. Mild forms of preeclampsia usually do not exhibit symptoms, though there are some red flags like proteinuria, excessive swelling of face and hands, weight gain, headaches and dizziness, irritability, shortness of breath, nausea, vomiting, blurred vision, and sensitivity to light.

Complications of hypertension during pregnancy

If hypertension has progressed to a severe state, it can pose a number of health risks for mother and baby:

• Decreased blood flow to the placenta leading to the baby receiving less oxygen and nutrients resulting in slow growth and low birth weight. Preterm babies have a higher risk of breathing problems, infection, and other complications.
• Placental abruption is the separation of the placenta from the inner wall of the uterus (womb) before delivery. Severe abruption may lead to heavy bleeding, which is life-threatening for mother and baby.
• Injury to your brain, heart, lungs, kidneys, liver, and other major organs.
• Premature birth may be advised by your obstetrician if your baby is not receiving adequate nutrients or if the mother’s life is in danger.
• Cardiovascular diseases may crop up in the future. The likelihood rises significantly if the mother has experienced preeclampsia or have delivered a premature baby due to high blood pressure during pregnancy.

New test to screen for preeclampsia during pregnancy

Biochemical substances such as angiogenic growth factors (namely sFIt-1 and PIGF) play a major role in the development of preeclampsia imbalance. These growth factors are thought to be in mainly responsible. By taking some blood, these growth factors can be measured to identify patients that need close monitoring. Patients with low risk can be reassured and continue pregnancy as per normal.

Managing high blood pressure before and during pregnancy

Blood pressure can be managed by taking the right steps:

• Attend a pre-pregnancy check-up up to a year before you decide to have a child. The visit will allow you to detect any pre-existing conditions and work on keeping them under control.
• Maintain a healthy lifestyle of a balanced diet and regular exercise.
• Avoid smoking, drinking, and consuming any illicit substances.

Effects of hypertension on childbirth and breastfeeding

Women with hypertension may be advised to induce labour before their due date in order to avoid complications. The timing of delivery depends on degree of severity of your blood pressure, presence of end-stage organ damage, as well as presence of complications to the baby. Severe preeclampsia medication may be given during labour to stave away seizures.

Breastfeeding is not contraindicated. However, the obstetrician needs to make adjustments to the types of medication