If you had high blood pressure before you conceived a baby or it develops during the first 20 weeks of pregnancy, your condition is called chronic hypertension. Women may have high blood pressure for different reasons—either because it runs in their family or because of an underlying condition, such as kidney disease.
Only 5 – 8 percent of all pregnant women have their pregnancies complicated by chronic hypertension, but those who do need to be closely monitored. As a normal part of pregnancy, blood pressure may fall at the end of the first trimester and, in the third trimester, it may rise to whatever it was prior to pregnancy. If blood pressure rises too much, it can increase the risk of stroke and other complications.
If your top number in a blood pressure reading (the pressure when the heart contracts) is 140 or greater, or the bottom number (the pressure when your heart relaxes) reads 90 or greater, you have chronic hypertension. One of the biggest concerns linked to uncontrolled chronic hypertension is the increased possibility of a related health condition—preeclampsia. Preeclampsia is a pregnancy-related condition that includes increased blood pressures. It can disrupt the normal function of many organs in a mother’s body, including the kidneys and liver. Preeclampsia can have a serious effect on a pregnancy, such as a higher risk of bleeding or seizures.
Another risk of uncontrolled chronic hypertension is that it can cause the placenta to separate from the wall of the uterus, resulting in premature birth. It can also interfere with normal development of the placenta, which can affect your baby’s nutrition and growth.
If you have uncontrolled chronic hypertension and you get pregnant, the possible complications are significant enough that your pregnancy will be considered high-risk. For this reason, many pregnant women with high blood pressure are encouraged to seek prenatal care by maternal-fetal specialists such as those found at Riley at IU Health. These specialists can guide you and your baby toward a healthy pregnancy, and care for any special needs you or your baby may have before, during or after birth, including diagnosis, monitoring, treatment and delivery.
It is always a good idea to stay in tune with your body and watch for signs of high blood pressure, but especially so during pregnancy. Typical signs that yours is running higher than usual are headache and swelling. Your doctor may also want to run certain tests to check your kidney function before you get pregnant. Women who are overweight may also be encouraged to lose weight prior to getting pregnant.
While it is normal for the feet and ankles to swell during pregnancy, you should call your doctor if your face, hands and calves swell. Pregnant women should watch for a change in their baby’s movement patterns, especially during the third trimester. A decrease in fetal activity is reason to contact your physician.
If you have chronic hypertension, you may have more frequent prenatal visits, especially during your third trimester, when blood pressure is prone to rise in most pregnancies. Doctors will keep a close watch on your blood pressure throughout pregnancy, and they may ask you to check your blood pressure at frequent intervals. You may have more than one ultrasound to monitor your baby’s growth, plus blood tests to monitor your liver and kidney function and urine tests to watch for loss of protein. Additional fetal monitoring may be recommended to make sure your baby is doing well.
If you plan to get pregnant and you have high blood pressure that is controlled by medication, you should see your physician prior to conception. Some common blood pressure medications cannot be used because they are not safe for unborn babies. Certain classes of medications can increase the risk of fetal kidney failure or birth defects, and your physician may suggest a change of medication to control blood pressure.
During your pregnancy, taking your medications as prescribed and eating a nutritious diet that is low in sodium can help you manage chronic hypertension. Unless your physician restricts your activity level, moderate exercise may be a healthy part of your routine during pregnancy.
Doctors sometimes recommend early delivery to avoid the risk of mothers having a stroke or organ dysfunction. This increases the likelihood that a baby will be born by cesarean section.
Visit the following websites for reliable information about chronic hypertension.
Riley at IU Health offers a broad range of supportive services to make life better for families who choose us for their children's care.
This professional organization for physicians provides patient education resources about conditions such as chronic hypertension during pregnancy.
As part of the National Institutes of Health, the NHLBI shares information with the public about conditions such as chronic hypertension in pregnancy.