Hypertension and preeclampsia during pregnancy

Hypertension occurs when the blood pressure in your arteries is abnormally high. This condition affects roughly 5 to 10 percent of pregnant women. If hypertension is accompanied by organ malfunction, it’s known as preeclampsia. About 1 to 2 percent of pregnant women in Quebec develop preeclampsia.

Causes

As blood is pumped through your body, it exerts pressure on the arterial walls. A healthy person’s blood pressure is around 120 mm Hg when their heart contracts and around 80 mm Hg between contractions. This is expressed as a blood pressure of 120/80.

Hypertension is defined as a blood pressure higher than 140/90. Some women already have high blood pressure before becoming pregnant. This is the case for about 1 percent of expectant moms. High blood pressure that develops during pregnancy, generally after the 20th week, is called gestational hypertension. The cause of this disorder is unknown.

Gestational hypertension can sometimes put a strain on some of the mother’s organs, such as her heart or kidneys, and make it difficult for them to function properly. This condition is known as preeclampsia. Certain symptoms may be warning signs of organ dysfunction. For example, protein buildup in the urine may point to a kidney problem.

In rare cases, preeclampsia can occur after the baby is born, usually within 48 hours of delivery.

Symptoms

Women don’t generally exhibit symptoms of hypertension. In most cases, it’s only detected when the doctor takes a blood pressure reading during a pregnancy follow-up.

However, women with preeclampsia may experience the following symptoms:

• New severe and persistent headaches
• Pain in the upper abdomen
• Nausea and vomiting
• Vision problems (blurred vision, seeing spots, etc.)
• Chest pain
• Difficulty breathing due to fluid buildup in the lungs

If these symptoms occur, it’s best to consult your doctor, midwife, or hospital birthing unit promptly.

Complications

In general, if hypertension isn’t accompanied by protein in the urine, it will have little impact on the woman’s pregnancy and delivery.

However, preeclampsia can trigger a number of complications.

• Increased blood pressure can interfere with the flow of nutrients to the placenta, which can slow the baby’s growth.
• Preeclampsia can lead to placental abruption, which can cause preterm delivery.
• Severe preeclampsia can cause the mother to develop liver complications and blood clotting issues. It can also cause seizures, and even hemorrhaging in the brain.

In severe cases, the doctor may decide to induce labour before you’ve reached full term. Hypertension therefore increases the risk of premature birth. Delivery by C-section is also more frequent.

Treatment

If your doctor notices that your blood pressure is high, they may want to run blood and urine tests to determine whether you have preeclampsia. This will require you to go to your birthing centre.

If you have gestational hypertension without signs of preeclampsia:

• Your doctor will ask you to rest at home and significantly reduce your activities. You’ll also be told to pay attention to your baby’s movements and to take your own blood pressure readings.
• You may be prescribed medication to lower your blood pressure.
• You’ll be monitored more closely with regular evaluations of the baby’s heart, ultrasounds, and blood or urine tests to make sure you don’t develop preeclampsia.
• Hospitalization may be necessary to monitor you and your baby’s health.

If you have preeclampsia:

• Once your condition has been confirmed, your doctor will arrange for a team of specialists at the hospital to closely monitor your pregnancy to avoid complications.
• It may be necessary to induce labour early to ensure you and your baby’s safety. In this case, you will be given medications to help your baby’s lungs develop.

Prevention

You can limit the risk of developing hypertension before pregnancy by maintaining a healthy weight, namely by adopting a varied and balanced diet and exercising regularly. You should also avoid smoking and drinking alcohol.

If you’ve had preeclampsia or are at high risk of developing it, your doctor may prescribe you aspirin during your pregnancy. This option will be assessed during your first pregnancy follow-up.

Things to keep in mind

• Gestational hypertension is an increase in blood pressure during pregnancy.
• Preeclampsia is a form of hypertension that causes organ dysfunction.
• If you notice symptoms of preeclampsia, see a doctor immediately, as the risk of complications is high.

Scientific review: Dr. Chantal Ouellet, physician Research and copywriting: The Naître et grandir team Updated: September 2020