Dizziness during pregnancy: When is it a concern?

By Laura Williamson, American Heart Association News

PeopleImages/iStock via Getty Images
(PeopleImages/iStock via Getty Images)

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Pregnancy often causes discomfort, whether it be morning sickness, backaches or swollen feet. But sometimes, health experts warn, a seemingly minor symptom could be a flag for something more.

Take dizziness.

"It's common, especially in the first trimester," said Dr. Silvana Ribaudo, an attending physician and assistant clinical professor in the department of obstetrics and gynecology at Columbia University in New York City.

But that doesn't mean it should be ignored, she warned. "The important thing is to assess holistically what might be going on. Is there a preexisting condition, like an iron deficiency? Or a cardiac arrhythmia (irregular heartbeat)? These things should be considered to potentially worked up."

Some dizziness is normal, especially in the early stages of pregnancy, Ribaudo said. Hormonal changes cause blood vessels to dilate and relax, causing blood pressure to drop. Lower blood sugar levels also may be a factor.

So, how does a woman know when to be concerned?

She might not, said Dr. Elizabeth Langen, co-director of the cardio-obstetrics program at the University of Michigan in Ann Arbor. And that's why women need to have good communication with their health care team during pregnancy.

"If a woman has any symptom that feels new or different, it's always appropriate to talk with her health care provider," said Langen, who also is a clinical associate professor of obstetrics and gynecology. "It's not her job to know whether she's sick or not. If the symptom is bothersome, she should bring it up with her health care team to see if it is or isn't dangerous."

Dizziness may occur for different reasons at different stages of pregnancy, Ribaudo said.

First trimester

During the first few weeks and months of pregnancy, many women experience nausea and vomiting that can be accompanied by dizziness or lead to dehydration, which in turn may cause dizziness.

Langen said women should be sure to stay well hydrated and stand up slowly to ward off feeling faint.

"For somebody who is generally healthy with no other known risk factors, if you feel dizzy, the first thing we recommend is to pay attention to hydration," she said. "Make sure you have electrolytes, intermittently drink sports drinks, wear compression socks. When you feel tired, allow your body to have the rest you need to feel good."

Fainting is one sign a woman should immediately consult her health care team, Langen said.

"If she actually does pass out and faint, that's very concerning," she said. "If she is dizzy after she sits down and rests or short of breath, that's not normal. Also, if she wakes up short of breath or can't lie flat without being short of breath."

A 2019 study in the Journal of the American Heart Association found women who faint during pregnancy, especially during the first trimester, may be at higher risk for poor pregnancy outcomes, such as preterm births, or may have an underlying heart condition, such as an irregular heartbeat. These women should be monitored closely during and after pregnancy.

Feeling short of breath could signal other, potentially serious heart conditions, Langen said.

Second trimester

For most women, the second trimester brings less nausea and related dizziness, Ribaudo said. "This is when appetite returns and energy improves," she said. "If dizziness occurs now, it's important to get a diagnosis."

One culprit could be vertigo. Unlike dizziness, vertigo – a false perception that things are moving – gets worse during any kind of movement, even while laying down and moving one's head from side to side, Ribaudo said. This condition requires a neurological exam to diagnose.

Another cause of dizziness could be the growing uterus putting too much pressure on the mother's blood vessels.

Third trimester

Dizziness during the third trimester could be a symptom of a hypertensive, or high blood pressure-related, disorder such as preeclampsia. This is a potentially dangerous condition that affects 1 in 25 pregnancies in the U.S. and typically begins after 20 weeks of pregnancy.

When preeclampsia occurs, the mother's high blood pressure can reduce blood flow to the fetus. It is diagnosed when persistent high blood pressure is accompanied by high levels of protein in the urine or decreased blood platelets, liver or kidney problems, fluid in the lungs or neurological issues.

For the baby, preeclampsia's risks include being born premature or small for gestational age, according to a 2021 report from the American Heart Association. For the mother, the condition increases the risk of maternal death and developing cardiovascular and other diseases later in life. If untreated, it can lead to seizures, a condition known as eclampsia.

"Every OB-GYN is worried about preeclampsia," Langen said. This is why health care professionals routinely check blood pressure levels during pregnancy.

Late pregnancy or after the baby is born

Peripartum cardiomyopathy is a rare but serious heart muscle disease that can cause heart failure in the later stages of pregnancy or after the baby is delivered, Langen said. Symptoms may include dizziness and shortness of breath. "People think after the baby is out, the risks for complications go away, but that's not so."

This is why it's important for women to seek follow-up care with their health care team after giving birth and to be aware of any unusual symptoms, she said.

Other causes

Iron deficiency is another potential culprit of dizziness while pregnant. Iron is essential for making oxygen-carrying hemoglobin in the body. As the fetus grows, the oxygen demand increases for the mom and her growing baby, requiring increased iron – and hemoglobin – in the blood. Not having enough is called iron deficiency anemia, and it may increase the risk for premature birth, having a baby with a low birthweight and infant mortality.

Iron levels fall slightly in most women during pregnancy, "but for some it's more than average," Langen said. "It can usually be treated with iron supplements."

Pulmonary embolisms, or blood clots blocking the arteries leading to the lungs, are another serious condition that can cause dizziness, Langen said. Other symptoms include shortness of breath and chest pain and should never be ignored because the condition can be fatal.

Speak up and be heard

Many maternal deaths, including those from cardiovascular diseases, can be prevented if problems are detected early, according to a 2022 report from the Centers for Disease Control and Prevention.

But even when women speak up, they may not be heard. For example, studies show Black women are three times more likely to die from pregnancy-related causes than their white peers and that structural racism and implicit bias play a role.

Ribaudo said women can better protect themselves by learning about pregnancy-related symptoms and complications when they make the decision to have a child.

"Be familiar with what your body will go through," she said. "Inform yourself and trust yourself. If you don't feel well, say something, because you're probably right."

And, Langen said, choose a health care team that makes you feel heard.

"You need a relationship with your health care provider that is safe and supportive," she said.

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