Low Blood Pressure in Pregnancy: Symptoms and Treatment

If you are pregnant, you have likely experienced symptoms of low blood pressuer. We'll tell you everything about this condition so you know how to take care of yourself.
Low Blood Pressure in Pregnancy: Symptoms and Treatment
Marcela Alejandra Caffulli

Reviewed and approved by the pediatrician Marcela Alejandra Caffulli.

Last update: 27 December, 2022

Blood pressure is one of the most controlled parameters during pregnancy. Usually, this vital sign undergoes variations as a result of changes in the woman’s circulatory system. All of them favor the natural tendency towards low pressure in the first weeks, which tends to normalize after week 20.

Do you want to know more about this? Keep reading!

Blood pressure, what does it represent?

Blood pressure is a vital parameter or sign that translates the force with which the heart pumps blood to the rest of the body. We obtain its values from a measurement of the pressure exerted on the arterial walls, by means of two different parameters, which are the following:

Systolic (or maximum) blood pressure

This reflects the pressure that the blood exerts when the heart ejects it, that is, during cardiac systole. Experts consider it to be normal during pregnancy when it ranges between 90 and 120 millimeters of mercury.

Diastolic (or minimal) blood pressure

This value represents the minimum pressure that the blood exerts on the arterial walls and coincides with the moment of cardiac relaxation (or diastole). Its normal values in pregnancy are those between 60 and 80 millimeters of mercury.

Low blood pressure in pregnant women

A pregnant woman with a headache.

Low blood pressure, or hypotension, is the condition that occurs when blood pressure records are below normal limits. It can occur for both systolic, diastolic, or both. But in general, there’s a decrease in minimal blood pressure.

Unlike hypertension, low blood pressure isn’t a disease. In fact, in pregnant women, it’s an expected condition that occurs as a consequence of the physiological changes of this period.

At the beginning of pregnancy, all these physiological changes seek to increase the flow of blood to the mother’s new organ: The placenta. This favors a decrease in the amount of blood that returns to the heart and translates into a decrease in diastolic blood pressure.

Toward the end of pregnancy, the size of the uterus becomes considerable and this causes compression of the large abdominal blood vessels (inferior vena cava and aorta), especially in the standing position or when the mother lies on her back. This phenomenon also affects the return of blood to the heart and favors hypotension. 

Symptoms having to do with low blood pressure in pregnancy

While hypotension is a physiological condition of pregnancy, some women experience bothersome symptoms from it. The intensity of these depends on many factors, among which are the usual blood pressure levels.

Among the most common clinical manifestations of hypotension in pregnancy, we can mention the following:

  • Palpitations
  • Dizziness
  • Nausea and vomiting
  • Fainting
  • Tiredness

In general, none of these symptoms is serious, but the context may favor the appearance of pregnancy complications. For example, if the mother passes out in public and hits herself hard.

Likewise, the mother’s basic condition is also a determining factor of risk. Sp, a mother who doesn’t hydrate well and suffers from hyperemesis gravidarum (severe vomiting) may become dehydrated more easily and require hospitalization.

Low blood pressure in pregnancy: Does it put the baby’s health at risk?

Hypotension doesn’t have to produce complications in the health of the fetus if the woman receives proper assistance. However, this issue generates certain controversies among specialists, as some argue that this condition could be associated with a lower birth weight in babies.

Beyond this fact, the mother’s blood pressure level can influence the flow of blood to the baby through the placenta.

In this sense, a sudden decrease in it, as can happen after the placement of antepartum anesthesia, could produce health problems for the mother or baby. And, when it happens, it must be resolved urgently.

How can low blood pressure of pregnancy be avoided?

Although it’s an expected phenomenon of pregnancy, there are some measures to prevent the symptoms that accompany hypotension.

Maintain proper hydration

Pregnancy produces changes in the woman’s body to favor the delivery of blood to the baby, such as an increase in blood volume.

Since most of the blood is made up of water, it’s essential that pregnant women ensure a sufficient intake every day. Especially when the losses are increased by high temperatures, exercise, or frequent vomiting.

Avoid prolonged fasting

In line with the above, a large part of the nutrients that travel through the maternal blood is destined to satisfy the demands of the baby. For this reason, maintaining a complete, balanced, and sufficient diet is essential, as well as avoiding  long hours of fasting.

Beware of high temperatures

High temperatures and low atmospheric pressures favor hypotension. For this reason, in this context, it’s important to ensure good hydration, use of light clothing, and stay in well-ventilated environments.

Get regular physical activity (walking and avoiding standing for a long time)

A pregnant couple hiking.

Physical activity favors the adaptation of the cardiovascular system to this new condition. Likewise, it produces beneficial changes in the mother’s mood and this also has a positive impact on her symptoms and her health in general.

Change positions very calmly

Sudden movements, such as jumping out of bed or bending over and standing up quickly, cause a drop in the level of blood reaching the brain. And momentarily, they cause a feeling of dizziness or can lead to fainting.

For this reason, it’ best to avoid high-speed position changes.

Rest on the left lateral decubitus

To promote the return of blood to the heart and thus avoid hypotension, experts recommend lying on the left side while resting in order to free the great vessels.

About low blood pressure in pregnancy

Hypotension in pregnancy is part of the many adaptive changes of the maternal body to this state. Without them, life could not develop within us.

Although low blood pressure during pregnancy has its purpose, the symptoms can sometimes be quite uncomfortable or annoying. For this reason, it’s essential that you discuss them with your obstetrician in order to learn about them and find the best way to cope with them.

All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

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This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.