High Blood Pressure During Pregnancy: What You Should Know About Hypertensive Disorders

Our bodies go through enormous changes during pregnancy – more so than at just about any other time in our lives! In order to grow human life inside of us during pregnancy, all of the following changes occur in our bodies: weight gain and water retention, changes in hormone levels, breast enlargement, loosening of ligaments and joints, alterations in vision, taste, and smell, skin and hair changes, and a significant increase in blood volume and number of red blood cells. This normal pregnancy-induced increase in circulating blood volume causes our hearts to have to pump harder and quicker, so it’s normal for pregnant women to have higher than normal heart rates. 

Some women also develop problems with blood pressure when they are pregnant. Blood pressure is a measure of how hard your heart has to work to pump blood throughout your body. Systolic blood pressure (the top number) is the pressure on the walls of your arteries when your heart is pumping blood. Diastolic blood pressure (the bottom number) is the pressure in your arteries between heartbeats, or when your heart is at rest. Normal blood pressure for all people, pregnant or not, is less than 120/80. Obstetricians and midwives check mothers’ blood pressure readings during every single prenatal visit. If a pregnant woman’s blood pressure is persistently higher than 120/80, she will be diagnosed with high blood pressure, which is also called hypertension.

According to the American College of Obstetricians and Gynecologists (ACOG), hypertension during pregnancy can be dangerous because it places extra stress on your heart and blood vessels throughout your body. This leads to an increased risk of stroke, heart disease, and kidney problems. High blood pressure also impacts blood flow from mom to baby across the placenta. This can lead to several pregnancy complications, including fetal growth restriction (from not enough oxygen and nutrients getting to the developing baby), miscarriage/stillbirth, and preterm birth. Hypertension during pregnancy also puts mothers at risk of developing a placental abruption, which is premature separation of the placenta from the uterine wall that can lead to bleeding and hemorrhage.

The three most common types of high blood pressure during pregnancy.

Chronic hypertension is diagnosed if you have a diagnosis of high blood pressure prior to getting pregnant and/or have elevated blood pressure readings during the first half of your pregnancy (prior to 20 weeks gestation). Some women with chronic hypertension are already on blood pressure medication when they get pregnant and others need to be started on medication for the first time during pregnancy. 

Gestational hypertension is when high blood pressure develops during the second half of pregnancy (after the 20th week of pregnancy). A pregnant woman’s blood pressure readings must be higher than 140/90 to be diagnosed with this problem. Hypertension in pregnancy is considered to be severe if a woman’s blood pressures are greater than 160/110. Most women with this condition do end up needing treatment with blood pressure lowering medications to prevent complications. Mothers with gestational hypertension are at a higher risk of developing hypertension later in life. Pregnant women with both chronic hypertension and gestational hypertension need to be carefully monitored for the development of a serious pregnancy complication called preeclampsia.

Preeclampsia develops after the 20th week of pregnancy and is associated with both hypertension and organ dysfunction. This medical condition can be extremely dangerous for mothers and babies – it can prevent a developing baby from getting enough blood and oxygen, and if severe, can harm mothers’ livers, kidneys, and/or brains, leading to a high risk of seizures and strokes.

Preeclampsia is associated with another pregnancy problem called HELLP syndrome, which causes damage to red blood cells and affects blood clotting. HELLP syndrome is diagnosed during pregnancy when all of the three signs/symptoms are present: hemolysis (red blood cell breakdown), elevated liver enzymes, and low platelet count. HELLP syndrome is a medical emergency and women with this condition need to deliver their babies ASAP to prevent serious long-term problems or death. Untreated preeclampsia can also lead to eclampsia, which causes uncontrollable seizures. Eclampsia used to be one of the most common reasons that women died during labor and delivery prior to the era of modern obstetrical care and health information. 

What causes pregnant women to develop preeclampsia?What are the risk factors of preeclampsia? 

Experts do not know the exact cause of preeclampsia. Per ACOG, risk factors for preeclampsia include all of the following.

Risk factors for women at high risk include:

  • Preeclampsia in a past pregnancy
  • Carrying more than one fetus
  • Chronic hypertension
  • Kidney disease
  • Diabetes mellitus
  • Autoimmune conditions, such as lupus (systemic lupus erythematosus or SLE)

Risk factors for women at moderate risk include:

  • Being pregnant for the first time
  • Body mass index (BMI) over 30
  • Family history of preeclampsia (mother or sister)
  • Being older than 35

How is preeclampsia diagnosed? 

In the early stages of preeclampsia, many women do not have any noticeable symptoms. The first sign of preeclampsia is often having higher than normal blood pressure readings during one or more prenatal visits. This is one reason why it is so important to not miss any of your prenatal visits! 

Other symptoms of preeclampsia include swelling (edema), rapid weight gain, persistent headaches, abdominal pain, changes in vision, nausea, and vomiting, and difficulty breathing. Nausea and vomiting from preeclampsia can be differentiated from morning sickness as it usually starts during the second half of pregnancy. Severe preeclampsia is associated with additional symptoms, which include low platelets, abnormal kidney and liver function blood tests, fluid in the lungs, and/or severe headaches.  

What will happen if I develop preeclampsia?

Like gestational hypertension, preeclampsia can often be managed in the outpatient setting. Pregnant women with mild cases of preeclampsia need frequent blood pressure monitoring, to see their obstetricians more often than usual for prenatal care (i.e. up to 1-2 times per week), and have additional ultrasounds to evaluate fetal well-being. Mothers with milder forms of gestational hypertension and preeclampsia often have labor induced around 37 weeks gestation to prevent the development of additional complications. 

Many women with severe preeclampsia need to be hospitalized and/or placed on bed rest. If preeclampsia is severe enough, your OB/GYN might need to induce labor and delivery before 34-35 weeks' gestation. Babies who are born this early are admitted to the neonatal intensive care unit (NICU) after birth for problems related to being born prematurely. These problems may include respiratory distress (due to having immature lungs), difficulty staying warm, an immature and irregular breathing pattern, jaundice, low birth weight, and feeding challenges. 

It’s important for all premature babies, especially those admitted to the NICU, to get their moms’ breastmilk as their main source of nutrition. This means that if you give birth to a preemie, and would like to breastfeed, you will likely need to pump for weeks to months postpartum - a breast pump will become a necessity for you. 

Aeroflow Breastpumps strives to provide pumps and other necessary supplies to all moms through insurance. We can quickly and easily help you see if you qualify. Simply submit your information through our Qualify Through Insurance Form and let us take care of the rest! Your dedicated Specialist will work directly with your insurance company and healthcare provider to verify your coverage and will contact you to discuss your insurance-covered options.

About the Author

Jessica Madden, MD, is the Medical Director at Aeroflow BreastpumpsDr. Madden has been a board-certified pediatrician and neonatologist for over 15 years. She's currently on staff in the neonatal intensive care unit (NICU) at Rainbow Babies and Children’s Hospital in Cleveland, OH. She previously worked in the Boston and Cleveland Clinic Children’s Hospitals. In 2018 she started Primrose Newborn Care to provide in-home newborn medicine and lactation support. She also enjoys traveling, yoga, reading, and spending time with her children.

Information provided in blogs should not be used as a substitute for medical care or consultation.