How Does High Blood Pressure Affect Your Unborn Baby?

Reviewed on 5/4/2021

High blood pressure during pregnancy is common, and it can affect both the mother and baby. It can cause preterm delivery (premature birth that occurs before 37 weeks of pregnancy), low birth weight (baby weighs less than 5 pounds, 8 ounces at birth), fetal growth restriction, fetal death, and neonatal death.
High blood pressure during pregnancy is common, and it can affect both the mother and baby. It can cause preterm delivery (premature birth that occurs before 37 weeks of pregnancy), low birth weight (baby weighs less than 5 pounds, 8 ounces at birth), fetal growth restriction, fetal death, and neonatal death.

High blood pressure (hypertension) occurs when pressure in the arteries, the blood vessels that carry blood from the heart to the rest of the body, is higher than normal. 

  • Normal blood pressure is below 120/80
  • Blood pressure between 120/80 and 129/80 is elevated blood pressure
  • Blood pressure of 130/80 or above is considered high blood pressure

High blood pressure during pregnancy is common, and it occurs 1 in every 12 to 17 pregnancies among women aged 20 to 44 in the U.S.

High blood pressure during pregnancy doesn’t just affect the mother. High blood pressure can have the following effects on the unborn baby: 

  • Preterm delivery (premature birth that occurs before 37 weeks of pregnancy) 
  • Low birth weight (baby weighs less than 5 pounds, 8 ounces at birth)
  • Fetal growth restriction
    • High blood pressure in the mother can make it more difficult for the baby to get adequate oxygen and nutrients and it may grow more slowly
  • Fetal death
  • Neonatal death (death of the baby in the first 28 days of life)

There are several types of high blood pressure that can occur during pregnancy: 

  • Chronic hypertension 
  • Gestational hypertension
    • Occurs when a woman has high blood pressure during pregnancy and does not have protein in her urine or other heart or kidney problems
    • Generally diagnosed after 20 weeks of pregnancy or close to delivery and usually goes away after giving birth
    • Some women who develop gestational hypertension may have a higher risk of developing chronic hypertension in the future
  • Preeclampsia/eclampsia
    • Preeclampsia is a condition in which women who previously had normal blood pressure suddenly develop high blood pressure and protein in the urine or other problems after 20 weeks of pregnancy
    • Women with chronic hypertension can also get preeclampsia
    • Eclampsia is a medical emergency in which women with preeclampsia develop seizures
    • Postpartum preeclampsia is a rare condition and a medical emergency that occurs when women who did not have preeclampsia during pregnancy develop it after giving birth
    • HELLP syndrome (Hemolysis, Elevated Liver enzymes, Low Platelets) is considered a subtype of preeclampsia with severe features

What Are Symptoms of High Blood Pressure During Pregnancy?

High blood pressure usually doesn’t cause any symptoms. It is often dubbed “the silent killer” because many people don’t know they have high blood pressure until they develop a heart attack, kidney disease, or stroke.

Some pregnant women may have symptoms of high blood pressure, such as:

Not all women have symptoms of preeclampsia, but when symptoms occur, they may include:

  • Persistent headache 
  • Vision changes (blurred vision, seeing spots, or changes in eyesight)
  • Pain in the upper stomach area
  • Nausea or vomiting
  • Swelling of the face or hands
  • Sudden weight gain
  • Difficulty breathing

What Causes High Blood Pressure During Pregnancy?

The cause of high blood pressure during pregnancy is unknown but risk factors include: 

  • First pregnancy
  • Preeclampsia during a previous pregnancy
  • A family history of preeclampsia
  • Chronic high blood pressure
  • Chronic kidney disease
  • A history of thrombophilia (a condition that increases risk of blood clots)
  • Multiple pregnancy (twins, triplets, etc.)
  • Pregnancy occurred using in vitro fertilization
  • Type 1 or type 2 diabetes
  • Obesity
  • Lupus 
  • Being African-American
  • Age younger than 20 years or over 40 years 

How Is High Blood Pressure During Pregnancy Diagnosed?

High blood pressure is diagnosed using a pressure cuff (sphygmomanometer) to get a blood pressure reading. Blood pressure is checked at prenatal visits. 

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What Is the Treatment for High Blood Pressure During Pregnancy?

Treatment for chronic hypertension during pregnancy depends on how high the pressure is. 

  • In the first half of pregnancy, blood pressure normally drops and if blood pressure is only mildly elevated, it may stay that way or return to normal during pregnancy
    • In this case, a doctor may recommend blood pressure medication be reduced or stopped during pregnancy
  • Severe hypertension or health problems associated with it may require starting or continuing blood pressure medication during pregnancy

Treatment for gestational hypertension depends on how close a woman is to her due date. 

  • If a woman is close to her due date and the baby is developed enough, a doctor may recommend delivering the baby as soon as possible
  • If hypertension is mild and the baby is not yet fully developed, a doctor may recommend:
    • Resting, lying on the left side to take the weight of the baby off the major blood vessels
    • Increasing prenatal checkups
    • Reducing salt intake
    • Drinking 8 glasses of water each day
  • If hypertension is severe, a woman may be treated with blood pressure medications until she is far enough along to safely deliver the baby

Treatment for mild preeclampsia may include: 

  • Monitoring fetal movement by doing a daily kick cunt
  • Blood pressure measurement at home
  • Visiting the ob-gyn once or twice weekly
  • Delivery may be considered at 37 weeks of pregnancy either by inducing labor with medications or via a cesarean birth (C-section)

Women who have preeclampsia with severe features may need to be treated in the hospital. 

  • For women at least 34 weeks pregnant, delivery may be considered as soon as the mother’s condition is stable
  • Women who are less than 34 weeks pregnant and in stable condition may be able to wait to deliver the baby
    • Corticosteroids may be given to help the fetus’s lungs mature
    • The mother may be given medications to reduce blood pressure and help prevent seizures
    • Immediate delivery may be considered if the mother’s health or the fetus’s health worsens

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Reviewed on 5/4/2021
References
https://www.cdc.gov/bloodpressure/pregnancy.htm

https://www.acog.org/womens-health/faqs/preeclampsia-and-high-blood-pressure-during-pregnancy

https://americanpregnancy.org/healthy-pregnancy/pregnancy-complications/gestational-hypertension-859/