What is blood pressure?
Blood pressure is the pressure in the blood vessels in your body. It is the force with which the blood moves through the blood vessels. Doctors and nurses measure blood pressure by putting a cuff around your upper arm. Then they listen to your blood flow with a stethoscope. High blood pressure (also called hypertension) occurs when your blood moves through your blood vessels at a higher pressure than normal.
What are the different types of high blood pressure during pregnancy?
There are three types of high blood pressure in pregnant women:
- Chronic hypertension: High blood pressure that develops before the 20th week of pregnancy or is present before the woman becomes pregnant. Sometimes a woman has high blood pressure for a long time before she gets pregnant, but she doesn’t know it until her first prenatal check-up.
- Gestational hypertension: Some women just get high blood pressure near the end of pregnancy. They don’t have any other associated symptoms.
- Pregnancy-induced hypertension (PIH), also called toxemia or preeclampsia: This condition can cause serious problems for both the mother and the baby if left untreated. PIH develops after the 20th weeks of pregnancy. Along with high blood pressure, it causes protein in the urine, blood changes and other problems.
What are the risks of PIH to the baby and me?
PIH can prevent the placenta (which gives oxygen and food to your baby) from getting enough blood. If the placenta doesn’t get enough blood, your baby gets less oxygen and food. This can cause low birth weight and other problems for the baby.
Most women who have PIH still deliver healthy babies. A few develop a condition called eclampsia (PIH with seizures), which is very serious for the mother and baby, or other serious problems. Fortunately, PIH is usually detected early in women who get regular prenatal care, and most problems can be prevented.
What are the symptoms of PIH?
If you have any of the following symptoms of PIH, call your doctor right away:
- Severe headaches
- Vomiting blood
- Excessive swelling of the feet and hands
- Smaller amounts of urine or no urine
- Blood in your urine
- Rapid heartbeat
- Excessive nausea
- Ringing or buzzing sound in ears
- Excessive vomiting
- Double vision
- Blurred vision
- Sudden blindness
- Pain in the abdomen (tummy)
Does high blood pressure mean I have PIH?
Not necessarily. If your doctor sees that your blood pressure is high, he or she will watch you closely for changes that could mean you have PIH. In addition to high blood pressure, women who have PIH also have excessive swelling. They may also have protein in their urine. Many women who have high blood pressure during pregnancy don’t have protein in their urine or extreme swelling, and don’t get PIH.
Does swelling mean I have PIH?
Swelling alone doesn’t necessarily mean you have PIH. Some swelling is normal during pregnancy. For example, your rings or shoes might become too tight. Swelling is more serious if it doesn’t go away after resting, if it’s very obvious in your face and hands or if it’s a rapid weight gain of more than 5 pounds in a week.
Who is at risk for PIH?
PIH is more common during a woman’s first pregnancy and in women whose mothers or sisters had PIH. The risk of PIH is higher in women carrying multiple babies, in teenage mothers and in women older than 40 years of age. Other women at risk include those who had high blood pressure or kidney disease before they became pregnant. The cause of PIH isn’t known.
What tests can show if I have PIH?
No one test diagnoses PIH. Your blood pressure will be checked during each doctor’s visit. A big rise in your blood pressure can be an early sign that you might have PIH. A urine test can tell if there is protein in your urine. Your doctor may order certain blood tests, which may show if you have PIH. If you have signs of PIH, your doctor may want to see you at least once a week and possibly every day.
How is high blood pressure treated in pregnant women?
The treatment will depend on the type of high blood pressure:
- Chronic hypertension: If you are already taking medicine for high blood pressure, your doctor may want you to keep taking that medicine. If that medicine is not safe for the baby, your doctor might want you to change to another medicine or to stop taking medicine while you are pregnant. Your doctor will pay special attention to how your baby is growing. You might have ultrasound exams more often. You might have some other tests near the end of your pregnancy to make sure that your baby is healthy. Your doctor will monitor you closely for signs of PIH.
- Gestational hypertension: This condition doesn’t need any treatment. But it can be hard to tell this condition from early or mild PIH, so your doctor will monitor you very closely to make sure your high blood pressure does not turn into PIH. Your doctor might tell you to take aspirin or extra calcium to prevent PIH. Your doctor might also tell you to lie on your left side while you are resting. This will improve blood flow and take weight off your large blood vessels.
- PIH: How your doctor treats this condition depends on how close you are to your due date and how you and your baby are doing. The only treatment that stops PIH is to deliver the baby. If your baby is born very early, it may have serious health problems. But your doctor may want your baby to be delivered early if you or the baby are very sick. If your doctor thinks it is safe for the pregnancy to continue to full term, he or she will monitor you and your baby very closely until delivery. You will see your doctor often and get blood tests. Your baby will also get some tests to make sure he or she is healthy. You might need to stay home from work and rest in bed. In some cases, hospitalization may be necessary.
A note about salt
One way to control high blood pressure when you’re not pregnant is to cut the amount of salt you eat. This is not a good idea if you have high blood pressure during pregnancy. Your body needs salt to keep up the flow of fluid in your body, so you need a normal intake of salt. Your doctor will tell you how much salt to eat each day and how much water you should drink each day.
If my doctor decides to deliver the baby early, will I have to have a Cesarean section?
This is up to your doctor and you. A Cesarean section (an operation to deliver the baby) is more likely if your health or your baby’s health is in danger. If things aren’t this serious, your doctor may use medicine (such as oxytocin) to start your labor, and you can deliver your baby through a vaginal delivery.
What happens to high blood pressure after delivery?
- Chronic hypertension: Your blood pressure will probably stay high after you have your baby. You will have to keep taking medicine for high blood pressure, watch your diet and exercise.
- Gestational hypertension: Your blood pressure will go back to normal within a few weeks after you have your baby, but you are more likely to develop chronic high blood pressure later in life.
- PIH: Your blood pressure will go back to normal within a few weeks after you have your baby.
Why is high blood pressure during pregnancy a problem?
High blood pressure during pregnancy can cause the following problems for you and your baby:
- Chronic hypertension: High blood pressure can make your baby grow too slowly, or not get enough nutrients or oxygen. This can hurt your baby’s health. Women who have chronic hypertension are also more likely to develop PIH, which can be very dangerous.
- Gestational hypertension: This condition does not cause any problems for you or your baby, but it can increase the risk that you will develop high blood pressure later in life. Gestational hypertension can also turn into PIH.
- PIH: High blood pressure is not the main problem, but it is one of the main signs of this health condition. PIH can cause headaches, blurred vision, vision loss, abdominal pain and dizziness. It can cause slow growth of the baby, low birth weight and premature delivery. If you get PIH with seizures (called eclampsia), you and your baby are at risk of dying. Many doctors give magnesium sulfate to their patients during labor and for a few days afterward to help prevent eclampsia. Talk to your doctor about these things.
NHBPEP Report on High Blood Pressure in Pregnancy: A Summary for Family Physicians by MA Zamorski, M.D., M.H.S.A. and LA Green, M.D., M.P.H. (American Family Physician July 15, 2001, http://www.aafp.org/afp/20010715/263.html