The link between hypertension and preterm birth

When you think of someone who copes with high blood pressure — also known as hypertension — a pregnant woman isn't likely among the first to come to mind. However, the Centers for Disease Control and Prevention (CDC) reports that 1 in every 12 to 17 pregnant women experiences high blood pressure, which can result in a variety of problems, including preterm delivery.

High blood pressure is very common among all adults, which is why it is so important to understand the importance of maintaining healthy blood pressure levels and how blood pressure is measured. Blood pushes against the walls of your arteries as it is transported from your heart to other parts of your body, creating pressure. Your blood pressure is measured as two numbers:

When your heart beats (systolic blood pressure) / When your heart rests (diastolic blood pressure)

A normal blood pressure level is below 120/80. If that pressure becomes too high — measuring above 130/80 — the risk for other health problems increases. This is especially true for pregnant women.

Hypertension-related complications
One of the complications a pregnant woman with high blood pressure might experience is preterm birth, or giving birth before her 37th week of pregnancy, rather than after the 40th week. High blood pressure during a pregnancy makes it more difficult for a baby to get enough oxygen and nutrients to grow, leading to an early delivery.

According to the March of Dimes, babies born prematurely may experience long-term intellectual and developmental disabilities, which can affect how a child physically develops and learns. Premature babies may also experience the following:

• Low birth weight

• Increased hospital stay after birth

• Neurological disorders, behavior problems and mental health conditions

• Development of asthma and lung disease

• Dental problems

• Hearing and vision loss

• Increased risk of infections

• Intestinal disorders

• Cerebral palsy

Women can also experience health problems caused by high blood pressure during pregnancy. These include heart disease, kidney disease and stroke. Additional complications caused by high blood pressure when pregnant include preeclampsia, a severe blood pressure disorder that can affect all the mother's organs and lead to preterm delivery and increased health risks for the mother later in life; placental abruption, a medical emergency when the placenta prematurely detaches from the uterus; and the need for cesarean delivery.

This is why it is important for women to understand their risk for developing high blood pressure before becoming pregnant, as well as learn how to manage it.

Risk factors for hypertension
The CDC reports that some medical conditions, such as diabetes, can increase your risk for high blood pressure. The same is true of an unhealthy diet, physical inactivity, obesity, overconsumption of alcohol, and tobacco use.

Genetics, family history, race and ethnicity also play a role. Black people develop high blood pressure more often than other racial and ethnic groups do, and develop it earlier in life.

According to the San Diego County Perinatal Equity Initiative (PEI), which raises awareness of poor birth outcomes and inequities among Black women, Black infants are nearly 60% more likely to be born premature. They are also two times more likely to be born with low birth weight.

Managing high blood pressure during pregnancy
If you are diagnosed with high blood pressure during your pregnancy, the CDC offers the following recommendations:

• Get early and regular prenatal care.

• Talk to your doctor about any medicines you take.

• Keep track of your blood pressure with a home blood pressure monitor and contact your doctor if your blood pressure is higher than usual or if you have symptoms of preeclampsia - severe headaches, changes in your vision, upper abdominal pain, nausea, vomiting, decreased urine output and shortness of breath.

• Choose healthy foods and keep a healthy weight.

• Get regular physical activity.

• Avoid alcohol consumption and tobacco or other substance use.

After you give birth, pay attention to how you feel and go to the ER or call 911 right away if you have symptoms of preeclampsia.

Learn more about OBGYN, pregnancy and childbirth care at Sharp HealthCare.

This story was updated February 18, 2021, to reflect the most up-to-date information about pregnancy and newborn classes.