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High Blood Pressure in Pregnancy
Gestational hypertension or high blood pressure during pregnancy is one of the most common hypertensive disorders that women face during pregnancy. It is asymptomatic and affects about 5-10% of pregnant women. These are women who do not have hypertension before their pregnancy but develop it from 20 weeks of pregnancy onwards.
Developing high blood pressure during pregnancy can result in pregnancy complications and should be taken seriously. Furthermore, women who develop hypertension during pregnancy are five times more likely to develop high blood pressure later in life than the general population. At the same time, their risk of developing health problems like coronary artery disease, heart attack, stroke and heart failure in the long term will be about two times higher than the general population.
Types of High Blood Pressure During and After Pregnancy
Chronic hypertension
Hypertension is defined when an individual has a high blood pressure reading where their systolic pressure measures 140mmHg or more and/or a diastolic pressure of 90mmHg or more.
A normal blood pressure reading of a young healthy woman should be between 90/60mmHg to 120/80mmHg. Blood pressure readings between 130/85 to 139/89mmHg are considered borderline high blood pressure.
Chronic hypertension is a lifelong condition that can happen to women before pregnancy.
Women with chronic hypertension will have gestational hypertension.
Gestational hypertension
Gestational hypertension is diagnosed when a pregnant woman has a high blood pressure reading where her systolic pressure is 140mmHg or more and/or diastolic pressure is 90mmHg or more. It is also known as pregnancy-induced high blood pressure. Gestational hypertension usually goes away after the delivery of the baby, within two to three months.
Expectant mothers who have borderline high to high blood pressure should work with their health care provider to closely monitor and work to prevent high blood pressure from escalating into more severe hypertension.
Symptoms
Gestational hypertension is asymptomatic and does not present any symptoms. It can only be detected through regular blood pressure monitoring.
Causes
While the cause of gestational hypertension is unknown, there are factors that put expectant mothers at an increased risk.
Risk Factors
- Pre-existing conditions prior to pregnancy such as:
- Diabetes
- High blood pressure
- Overweight
- Autoimmune conditions such as:
- Lupus
- Underlying kidney disease
- Age
- Women who are at extreme ages during pregnancy, such as less than 20 years old or more than 40 years old
- History of preeclampsia or high blood pressure disorders during a previous pregnancy
- Family history
- Women whose family members have had gestational hypertension during their pregnancies
- Having multiple babies, i.e. twins, triplets, etc.
- Women who received assisted reproduction therapies
- Antiphospholipid syndrome
Complications
High blood pressure during pregnancy hinders blood flow to vital organs such as the liver, brain, uterus and placenta. This affects the baby’s growth and they tend to be smaller.
Up to 50% of women with gestational hypertension will eventually develop preeclampsia. This progression is more likely when hypertension is diagnosed before 32 weeks of pregnancy.
Treatment
Doctors will determine the best course of action based on the severity of the mother’s blood pressure, the overall health of the mother during pregnancy and their medical history. The doctor may run blood tests to rule out preeclampsia and ensure that vital organs are not affected. An ultrasound scan may also be conducted to estimate the baby’s weight.
To keep blood pressure under control, blood pressure medication that is safe for both mother and baby may be prescribed.
Preeclampsia
Preeclampsia is a potentially life-threatening complication resulting from untreated high blood pressure during pregnancy. Preeclampsia is diagnosed when the expectant mother has high blood pressure and protein in her urine. It affects 3 out of 100 pregnant women and usually develops after 20 weeks of pregnancy. Sometimes it can develop after the birth of the baby.
Symptoms
- High blood pressure
- Protein in the urine
- Sudden swelling in both feet and face
- Persistent headache
- Vision blurring
- Nausea or severe nausea and/or vomiting
- Abdominal pain
Complications
Preeclampsia can impair the expectant mother’s kidneys and liver and affect blood platelets and the heart. When the relaxation function of the heart is affected, it can cause water retention in the lungs typically during the third trimester, close to delivery. This could lead to the development of heart failure.
Preeclampsia can also cause fetal growth restriction as the blood supply to the uterus and placenta, which supplies nutrients and oxygen to the baby, is hindered. This may result in early delivery of the baby.
If preeclampsia is left untreated, eclampsia, the most severe form of pregnancy high blood pressure, can develop. In eclampsia, the mother could develop potentially life-threatening complications such as seizures or fits.
Treatment
Aggressive monitoring is needed in preeclampsia. In severe cases where treatment is ineffective and the condition of mother and baby worsens, delivery of the baby via caesarean section will be the only option.
Preventing Abnormal Blood Pressure During Pregnancy
- Preconception screening is encouraged so that health conditions such as diabetes, hypertension or weight issues can be flagged out.
- Expectant mothers are encouraged to maintain a heart-healthy lifestyle to prevent elevated blood pressure. This includes:
- Having a healthy diet to maintain a healthy weight. While the amount of weight gain differs based on pre-pregnancy weight, pregnant women are encouraged to have a BMI of between 18 and 23kg/m2.In general, healthy eating can optimise pregnancy outcomes and assist with the overall growth and development of the fetus. A healthy balanced diet consists of a diet rich in whole grains, fresh fruit and vegetables, lean protein, healthier vegetable oils and low-fat dairy products.In addition, avoid foods high in saturated and trans-fat, fatty cuts of meat, full-fat dairy, baked products, and sugar-sweetened beverages.Intake of essential nutrients is encouraged during pregnancy. Hence, pregnant women should include healthy foods high in folate, iron, calcium, and vitamin B12 in their diet as they will support their health and baby’s development and growth.
- Doing 150 minutes of moderate-intensity exercise per week. The Health Promotion Board recommends for pregnant women to reduce the intensity of activity and avoid contact sports or exercises with fall risk. Light cardiovascular exercises such as walks, runs and swims which help take pressure off joints are encouraged. According to the Singapore Physical Activity Guidelines, exercising before and during pregnancy is associated with a reduced risk of gestational diabetes, weight gain and a lowered risk of premature birth.
- Get adequate sleep of 6 to 8 hours a day to manage stress levels, a contributing factor to high blood pressure.
When to see a Doctor
A serious medical emergency can be prevented if gestational hypertension is detected early – either at regular prenatal care checks or through blood pressure monitoring at home. Women who discover high blood pressure during pregnancy should seek immediate review from their obstetrician and cardiologist to manage elevated blood pressure.
Conclusion
Grasp the key points on hypertension and pregnancy from our healthcare experts here:
No matter what stage of life you are at, continuous management of blood pressure is important to keep a serious medical condition such as heart disease from developing in the long run.
