While so much about a woman’s body changes during pregnancy, one thing that should remain fairly stable is blood pressure levels. You may be surprised to know that normal blood pressure readings for pregnant females should be the same as readings for women who are not pregnant.
Unfortunately, many women do experience high blood pressure during pregnancy, leading to potential complications for mom and baby alike. The good news is that patients and physicians can take steps to manage blood pressure in pregnant women, which usually results in good outcomes for mom and child.
According to the U.S. Centers for Disease Control and Prevention, approximately one in every 12 to 16 pregnancies among women ages 20 to 44 are affected by high blood pressure. With women now tending to become pregnant at older ages, high blood pressure among pregnant women is becoming more common.
As we mark February as American Heart Month, here is an overview of high blood pressure during pregnancy.
A blood pressure reading of 120/80 or less is considered a normal, healthy blood pressure reading. If the systolic reading—top number—is between 130 and 140 and the diastolic reading—bottom number—is between 81 and 89, that is considered prehypertension. Prehypertension is essentially a warning sign that you may develop high blood pressure down the road. High blood pressure, often called hypertension, is a reading of 140/90 or greater.
High blood pressure means that the force of blood against your artery walls is too strong. Mild cases of high blood pressure usually aren’t dangerous to the baby, but if blood pressure is very high, the amount of oxygen the baby receives in the womb can decrease. That can affect the baby’s growth.
Some women develop high blood pressure before becoming pregnant, a condition called chronic hypertension. Physicians don’t depend on a single blood pressure reading to make this diagnosis but instead rely on several readings over a period of a few weeks.
Women who are overweight are at higher risk of developing high blood pressure during pregnancy. Other risk factors include:
• Age: The risk of high blood pressure increases with age. Women in their late 30s and early 40s are more likely to have high blood pressure than their younger counterparts.
• Family history: Women with a family history of hypertension, especially among their parents, are as much as twice as likely to have chronic hypertension.
• Race: African American women are at higher risk of high blood pressure while pregnant.
• Poor diet and lack of exercise: Diets high in sodium can lead to high blood pressure, as can excessive alcohol consumption. Regular exercise can lower the risk of high blood pressure.
Many women with chronic hypertension never experience symptoms so that’s one reason to see your physician prior to pregnancy and to also attend your regular prenatal visits. It’s during these visits that ob-gyns will check your blood pressure and detect any problems.
Medication can help control chronic high blood pressure during pregnancy. Women who are on blood pressure medications before becoming pregnant may need to switch medications if the one(s) they are using are not safe for pregnant women and their babies. Some women won’t need medication and instead will be carefully monitored. It’s not uncommon for blood pressure levels to decrease during the second trimester, but they tend to go back up in the third trimester, at which point medication may be necessary.
We also recommend pregnant women with high blood pressure take a baby aspirin each day to help ward off preeclampsia, a serious condition that can lead to complications for mother and baby.
Preeclampsia is high blood pressure that develops after 20 weeks of pregnancy, though it usually occurs around the 34th week.
It is usually characterized by a finding of protein in the urine. It’s worth noting that some patients have preeclampsia without protein in the urine but instead experience liver or kidney dysfunction. To diagnose preeclampsia, physicians look at blood pressure readings, urine samples and blood tests.
Experts don’t know what triggers preeclampsia. Risk factors are similar to those associated with chronic hypertension. We do know that if a woman had preeclampsia during her first pregnancy, she is likely to have it in future pregnancies. And we know that some women with chronic hypertension also develop preeclampsia.
Others at high risk of preeclampsia include pregnant women with:
• Pregestational diabetes
• Chronic hypertension
• Kidney disease
Women carrying multiples are also at increased risk, as are those who are aged 35 or older.
Just as with chronic hypertension, many women with preeclampsia don’t have symptoms. Other women experience rapid weight gain; swelling of the hands and face; headaches; vision problems; and breathing trouble.
Preeclampsia can prevent the fetus from getting enough nutrients and oxygen. That can lead to intrauterine growth restriction, meaning the fetus doesn’t grow at the normal rate. Preeclampsia can lead to eclampsia, an extremely serious but rare condition that can lead to seizures in pregnant women. While the mom experiences a seizure, oxygen flow to the baby is reduced. The cure for preeclampsia is childbirth. Depending on the severity of the situation, a preterm delivery may be necessary to preserve the life of the mom and the baby.
Preeclampsia usually resolves after the mom delivers the baby, but in some cases, women can first develop preeclampsia after giving birth. Though it usually develops within a day or two after birth, there are cases where women have developed preeclampsia up to eight weeks postpartum. Called postpartum preeclampsia, this condition requires immediate treatment to prevent seizures and stroke.
Convenient, Coordinated Care
Due to the COVID-19 pandemic, the Mid-Atlantic Permanente Medical Group developed an innovative plan to replace some prenatal in-office visits with phone or video visits that women can attend from the comfort of their homes. We’ve expanded this program to care for our higher-risk patients, including those with hypertension. We provide high-risk women blood pressure cuffs so they can take readings at home, and we have a dedicated team of nurses who check in weekly with patients to review the home blood pressure readings and assess for signs of complications.
Our integrated model also enables us to work closely with cardiologists and maternal-fetal medicine specialists so care for women with high blood pressure is well coordinated. Women with a history of preeclampsia will be seen by a maternal-fetal medicine specialist, who can perform advanced ultrasounds to better monitor the condition of the mom and baby.
Pregnant women with a history of heart disease or a pregnancy that was extremely complicated may be referred to a cardiologist. If the baby’s heart is of concern, the mom is referred to a pediatric cardiologist.
As an obstetrician-gynecologist, I recommend anyone contemplating a pregnancy take some time to improve their overall health before becoming pregnant. That means eat a well-balanced diet, exercise regularly and talk to your physician about any health problems you may have. Controlling diabetes or high blood pressure before becoming pregnant will lead to a smoother pregnancy.
That said, just because you have high blood pressure doesn’t mean your pregnancy will be difficult. With care from your medical team, you and baby will be in great shape.
Carla Sandy, MD, is a board-certified obstetrician and gynecologist with the Mid-Atlantic Permanente Medical Group. She sees patients at the Kaiser Permanente Silver Spring Medical Center and provides care through, video visits, phone calls and office visits.