High blood pressure during pregnancy

Blood pressure is the force of blood that pushes against the walls of your arteries. Arteries are blood vessels that carry blood away from your heart to other parts of the body. If the pressure in your arteries becomes too high, you have high blood pressure. High blood pressure also is called hypertension.

Your blood pressure reading is given as two numbers: the top (first) number is the pressure when your heart contracts and the bottom (second) number is the pressure when your heart relaxes. A healthy blood pressure is 110/80. High blood pressure happens when the top number is 140 or greater, or when the bottom number is 90 or greater.

High blood pressure can stress your heart and cause problems during pregnancy. Some women have high blood pressure before they get pregnant. Others have high blood pressure for the first time during pregnancy. About 8 in 100 women (8 percent) have some kind of high blood pressure during pregnancy.

What kinds of high blood pressure can happen during pregnancy and how are they treated?
There are four main kinds of high blood pressure during pregnancy:

  1. Chronic hypertension. This is high blood pressure you already have before you get pregnant or that develops before 20 weeks of pregnancy. It doesn’t go away once you give birth.

    During pregnancy, your health care provider makes sure your blood pressure is under control. Without treatment, chronic hypertension can lead to health problems like heart failure or stroke. He also checks for signs of preeclampsia.

    Your provider changes any medicine you take if it’s not safe for your baby. Some blood pressure medicines, called ACE inhibitors and angiotensin receptor blockers, can harm your baby during pregnancy. You may be able to stop taking your medicine during the first half of pregnancy. Blood pressure tends to fall during this time. Don’t stop taking any medicine, though, before you talk to your health care provider.

    Your provider may use ultrasound and fetal heart rate testing to check your baby’s growth and health. You may need to give birth early if your hypertension gets worse or if you go on to have preeclampsia.
  2. Preeclampsia. This is a high blood pressure that only pregnant women can get. It happens when you have both high blood pressure and protein in your urine. It usually starts after 20 weeks of pregnancy and goes away after you give birth.

    Preeclampsia can be a serious medical condition. In rare cases, it can become a life-threatening condition called eclampsia. Eclampsia causes seizures and can lead to coma. Even if you have mild preeclampsia, you need treatment to make sure it doesn’t get worse. Without treatment, preeclampsia can cause kidney, liver and brain damage. Treatment depends on how severe your preeclampsia is. Treatment can range from careful monitoring by your provider to inducing labor.
  3. Gestational hypertension. This is high blood pressure that only pregnant women can get. Unlike preeclampsia, women with gestational hypertension don’t have protein in their urine. This condition starts after 20 weeks of pregnancy and goes away after you give birth. Some women with gestational hypertension have preeclampsia later in pregnancy.

    We don’t know how to prevent gestational hypertension. But if you’re overweight or obese, reaching a healthy weight before pregnancy may lower your chances of having this condition.

    During pregnancy, your provider checks your blood pressure and urine at every prenatal visit to monitor your hypertension. She may use ultrasound and fetal heart rate testing to check your baby’s growth and health.
  4. Chronic hypertension with preeclampsia. About 1 in 4 women with chronic hypertension (25 percent) have preeclampsia later in her pregnancy.

    During pregnancy, your provider montiros your conditiona at every prenatal visit. She may use ultrasound and fetal heart rate testing to check your baby's development.

What pregnancy complications can high blood pressure cause?
If you have high blood pressure during pregnancy, your provider can help you manage most health problems through regular prenatal care. Pregnant women with high blood pressure are more likely than women without high blood pressure to have these complications:

  • Low birthweight. This is when a baby weighs less than 5 pounds, 8 ounces. High blood pressure can narrow blood vessels in the uterus (womb). Your baby may not get enough oxygen and nutrients, causing him to grow slowly.
  • Premature birth. This is birth that happens too early, before 37 completed weeks of pregnancy. Even with treatment, a pregnant woman with severe high blood pressure or preeclampsia may need to give birth early to avoid serious health problems for her and her baby.
  • Placental abruption. In this condition the placenta separates from the wall of the uterus before birth. It can separate partially or completely. If this happens, your baby may not get enough oxygen and nutrients. Vaginal bleeding is the most common symptom of placental abruption after 20 weeks of pregnancy. If you have vaginal bleeding during pregnancy, contact your health care provider immediately.

How is high blood pressure diagnosed during pregnancy?
Most women with high blood pressure during pregnancy have no symptoms. So it’s important to go to all your prenatal care visits. Your provider measures your blood pressure and checks your urine for protein at every visit. If you have high blood pressure, your provider can help you manage it.

What can you do about high blood pressure before pregnancy?
If you have chronic hypertension before pregnancy, go for a preconception checkup before you try to get pregnant. Making healthy choices before pregnancy can help you manage your blood pressure. For example, do something active and eat healthy foods every day to help you get to or stay at a healthy weight. If you smoke, quit. Smoking is dangerous for people with high blood pressure because it damages blood vessel walls. Making these changes can help you have a safer pregnancy.

Last reviewed March 2012

See also: HELLP syndrome, Preeclampsia

Most common questions

What is mononucleosis?

Mononucleosis (also called mono) is an infection usually caused by the Epstein-Barr virus (EBV). It’s sometimes caused by another virus called cytomegalovirus (CMV). EBV and CMV are part of the herpes virus family. Mono is most common in teenagers and young adults, but anyone can get it. Mono is called the “kissing disease” because it’s usually passed from one person to another through saliva. In addition to kissing, it can also be passed through sneezing, coughing or sharing pillows, drinks, straws, and toothbrushes.

You can have mono without having any symptoms. But even if you don’t get sick, you can still pass it to others. Symptoms can include:

  • Achy muscles
  • Belly pain
  • Fatigue (feeling tired all the time)
  • Fever
  • Sore throat
  • Swollen glands in your neck

If your symptoms don’t go away or get worse, tell your health care provider. He’ll most likely do a physical exam and test your blood to find out for sure if you have mono.

There’s no vaccine to prevent mono. There’s also no specific treatment. The best care is to take it easy and get as much rest as you can. It may take a few weeks before you fully recover.

Can Rh factor affect my baby?

The Rh factor may be a problem if mom is Rh-negative but dad is Rh-positive. If dad is Rh-negative, there is no risk.

If your baby gets her Rh-positive factor from dad, your body may believe that your baby's red blood cells are foreign elements attacking you. Your body may make antibodies to fight them. This is called sensitization.

If you're Rh-negative, you can get shots of Rh immune globulin (RhIg) to stop your body from attacking your baby. It's best to get these shots at 28 weeks of pregnancy and again within 72 hours of giving birth if a blood test shows that your baby is Rh-positive. You won't need anymore shots after giving birth if your baby is Rh-negative. You should also get a shot after certain pregnancy exams like an amniocentesis, a chorionic villus sampling or an external cephalic version (when your provider tries to turn a breech-position baby head down before labor). You'll also want to get the shot if you have a miscarriage, an ectopic pregnancy or suffer abdominal trauma.

I had a miscarriage. How long should I wait to try again?

Before getting pregnant again, it's important that you are ready both physically and emotionally. If you don't need tests or treatments to discover the cause of the miscarriage, it's usually OK for you to become pregnant after one normal menstrual cycle. However, it may take longer for you to feel emotionally ready to be pregnant again. Everyone responds differently to a miscarriage. Only you will know when you are ready to try to get pregnant again.

Are gallstones common during pregnancy?

Not common, but they do happen. Elevated hormones during pregnancy can cause the gallbladder to function more slowly, less efficiently. The gallbladder stores and releases bile, a substance produced in the liver. Bile helps digest fat. When bile sits in the gallbladder for too long, hard, solid nuggets called gallstones can form. The stones can block the flow of bile, causing indigestion and sometimes serious pain. Staying at a healthy weight during pregnancy can help lower your risk of gallstones. Exercise and eating foods that are low in fat and high in fiber, like veggies, fruits and whole grains, can help, too. Symptoms of gallstones include nausea, vomiting and intense, continuous abdominal pain. Treatment during pregnancy may include surgery to remove the gallbladder. Gallstones in the third trimester can be managed with a strict meal plan and pain medication, followed by surgery several weeks after delivery.

©2013 March of Dimes Foundation. The March of Dimes is a non-profit organization recognized as tax-exempt under Internal Revenue Code section 501(c)(3).