High blood pressure during pregnancy
High blood pressure can cause problems for you and your baby during pregnancy, including preeclampsia and premature birth.
High blood pressure usually doesn’t cause signs or symptoms. Go to all your prenatal care visits so your provider can check your blood pressure.
If you need medicine to keep your blood pressure under control, take it every day.
If you’re at high risk for preeclampsia, your provider may want you to take low-dose aspirin to help prevent it.
What is high blood pressure?
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 (also called hypertension). High blood pressure can put extra stress on your heart and kidneys. This can lead to heart, disease, kidney disease and stroke.
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. If you have high blood pressure, talk to your health care provider. Managing your blood pressure can help you have a healthy pregnancy and a healthy baby.
How do you know if you have high blood pressure?
Your blood pressure reading is given as two numbers: the top (first) number is the pressure when your heart contracts (gets tight) and the bottom (second) number is the pressure when your heart relaxes. A normal blood pressure is 119/79 or lower. High blood pressure happens when the top number is 140 or greater, or when the bottom number is 90 or greater. Your blood pressure can go up or down during the day.
At each prenatal care checkup, your provider checks your blood pressure. To do this, she wraps a cuff (band) around your upper arm. She pumps air into the cuff to measure the pressure in your arteries when the heart contracts and then relaxes. If you have a high reading, your provider can recheck it to find out for sure if you have high blood pressure.
What pregnancy complications can high blood pressure cause?
High blood pressure can cause problems for you and your baby during pregnancy, including:
- Preeclampsia. This is when a pregnant woman has high blood pressure and signs that some of her organs, like her kidneys and liver, may not be working properly. Signs and symptoms of preeclampsia include having protein in the urine, changes in vision and severe headaches. Preeclampsia can be a serious medical condition. 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. In rare cases, it can lead to life-threatening conditions called eclampsia and HELLP syndrome. Eclampsia causes seizures and can lead to coma. HELLP syndrome is when you have serious blood and liver problems.
- Premature birth. This is birth that happens too early, before 37 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.
- Low birthweight. This is when a baby is born weighing 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.
- Placental abruption. This is a serious condition in which the placenta separates from the wall of the uterus before birth. If this happens, your baby may not get enough oxygen and nutrients in the womb. You also may have serious bleeding from the vagina. The placenta grows in the uterus and supplies the baby with food and oxygen through the umbilical cord.
If you have high blood pressure during pregnancy, you’re also more likely have a cesarean birth (also called c-section). This is surgery in which your baby is born through a cut that your doctor makes in your belly and uterus.
What kinds of high blood pressure can affect pregnancy?
Two kinds of high blood pressure that can happen during pregnancy:
- Chronic hypertension. This is high blood pressure that you have before you get pregnant or that develops before 20 weeks of pregnancy. It doesn’t go away once you give birth. About 1 in 4 women with chronic hypertension (25 percent) has preeclampsia during pregnancy. If you’re at high risk for preeclampsia, your provider may treat you with low-dose aspirin to prevent it.
If you have chronic hypertension, your provider checks your blood pressure and urine at each prenatal care visit. You may need to check your blood pressure at home, too. Your provider may use ultrasound and fetal heart rate testing to check your baby’s growth and health. Your provider also checks for signs of preeclampsia.
If you were taking medicine for chronic hypertension before pregnancy, your provider makes sure it’s safe to take during pregnancy. If it’s not, he switches you to a safer medicine. Some blood pressure medicines, called ACE inhibitors and angiotensin receptor blockers, can harm your baby during pregnancy.
During the first half of pregnancy, blood pressure often falls. If you have mild hypertension and took medicine for it before pregnancy, your provider may lower the dose of medicine you take. Or you may be able to stop taking medicine during pregnancy. Don’t stop taking any medicine before you talk to your health care provider. Even if you didn’t take blood pressure medicine in the past, you may need to start taking it during pregnancy.
- Gestational hypertension. This is high blood pressure that only pregnant women can get. It starts after 20 weeks of pregnancy and goes away after you give birth.
It usually causes a small rise in blood pressure, but some women develop severe hypertension and may be at risk for more serious complications later in pregnancy, like preeclampsia.
During pregnancy, your provider checks your blood pressure and urine at every prenatal visit. She may use ultrasound and fetal heart rate testing to check your baby’s growth and health.
We don’t know how to prevent gestational hypertension. But if you’re overweight or obese, getting to a healthy weight before pregnancy may lower your chances of having this condition. And even though gestational hypertension usually goes away after birth, you may be more likely to develop hypertension later in life. Healthy eating, staying active and getting to a healthy weight after pregnancy can help prevent high blood pressure in the future.
How can you manage high blood during pregnancy?
Here’s what you can do:
- Go to all your prenatal care checkups, even if you’re feeling fine.
- If you need medicine to control your blood pressure, take it every day. Your provider can help you choose one that’s safe for you and your baby.
- Eat healthy foods. Don’t eat foods that are high in salt, like soup and canned foods. They can raise your blood pressure.
- Stay active. Being active for 30 minutes each day can help you manage your weight, reduce stress and prevent problems like preeclampsia.
- Don’t smoke, drink alcohol or use street drugs or abuse prescription drugs.
What can you do about high blood pressure before pregnancy?
Here’s what you can do:
- Get a preconception checkup. This is a medical checkup you get before pregnancy to take care of health conditions that may affect your pregnancy.
- Use birth control until your blood pressure is under control. Birth control is methods you can use to keep from getting pregnant.
- Get to a healthy weight. Talk to your provider about the weight that’s right for you.
- Eat healthy foods.
- Do something active every day.
- Don’t smoke. Smoking is dangerous for people with high blood pressure because it damages blood vessel walls.
Last reviewed: July, 2015