Dehydration is more common during pregnancy than at other times. Most cases of dehydration in pregnancy are mild, but severe dehydration can be dangerous for both the mother and the baby.
The fetus places intense demands on the body, and women who are pregnant need to consume extra nutrients. Morning sickness, as well as conditions that cause excessive vomiting, may also play a role in dehydration.
This article looks at how to identify dehydration, the effects of maternal dehydration on the baby, and how to prevent it from happening.
Generally, the first sign of dehydration is feeling thirsty.
People who feel thirsty after sweating, spending long periods of time in the heat, or going for long periods without water are especially likely to be dehydrated.
Other signs of dehydration include:
- a dry feeling in the throat or mouth
- dry, chapped lips
- dry-looking skin
- less elastic skin that looks sunken or thin
- less frequent urination
- dark-colored urine
- urinating less often
- not sweating, even in hot weather
- feeling weak or exhausted
- constipation, hard stools, and hemorrhoids
- feeling lightheaded
Some people may experience Braxton Hicks contractions when they are dehydrated.
When dehydration gets worse, feelings of thirst can disappear. Some signs of more severe dehydration during pregnancy include:
- dizziness and confusion
- a racing heart
- changes in the baby’s pattern of movement
- low blood pressure, which may cause dizziness or fainting
Severe dehydration can cause shock and organ failure. It may also harm the baby.
The causes of dehydration fall into two general categories:
Not drinking enough water
Although there are many recommendations available about how much water people should drink, needs vary from person to person. Pregnancy places additional demands on the body. So women generally need to drink more water during pregnancy than they did before they were pregnant.
Someone who is physically active or who lives in a hot climate will sweat more and will need more water.
Individuals who change their activity level suddenly or move to a warmer climate may need more water than they once did. If they do not adjust the amount they drink, they can become dehydrated.
People with eating disorders, particularly bulimia, may be more vulnerable to dehydration.
When dehydration happens because of not drinking enough water, it is often easy to fix by just drinking more water — particularly in the early stages of dehydration.
Not absorbing enough water
Some medical conditions, especially those that cause vomiting and diarrhea, can make it difficult for the body to absorb the water it needs.
Nausea and vomiting are more common during pregnancy than at other times. Those with hyperemesis gravidarum, which occurs in 3 percent of pregnancies, may experience intense vomiting that causes weight loss and dehydration.
Other health issues, especially those that affect metabolism, can cause dehydration. These include:
- kidney failure
- certain rare metabolic disorders
- intestinal disorders such as Crohn’s disease or celiac disease that make it difficult to absorb nutrients
People with an underlying medical condition are at an increased risk for dehydration in hot weather, following intense exercise, or when they do not drink enough water.
Mild dehydration is not typically dangerous in pregnancy as long as the woman quickly gets enough fluids. Severe dehydration can be dangerous for both the mother and the baby.
Dehydration can cause deficiencies in nutrients that are vital for the health of the pregnant woman and the developing baby.
Dehydration is not, however, the primary cause of preterm labor. A 2016 study found that those showing signs of preterm labor were no more likely to be dehydrated than those who were not experiencing preterm labor.
Rarely, dehydration can cause comas or even be fatal.
It can be difficult to self-diagnose whether dehydration is mild or severe. If drinking water or an electrolyte drink does not quickly improve symptoms, call an obstetrician or midwife. If it is the weekend or after hours, there might be an after-hours line that can help. If no such services are available, consider going to an urgent care provider.
Women should go to the hospital for dehydration when they:
- feel the baby’s pattern of movement changes
- begin to bleed or leak fluid
- experience contractions that they think might be a sign of premature labor
- have already been diagnosed with a serious medical condition, such as kidney failure
- experience vomiting or diarrhea for longer than 12 hours
- have stopped sweating despite drinking fluid
- are producing very little or no urine
- faint, have a seizure or feel confused
Those who have hyperemesis gravidarum or another medical condition should discuss with their doctor when it is time to go to the hospital.
If the doctor suspects that the woman’s symptoms constitute a medical emergency, they should seek emergency care.
Treatment for dehydration may include giving fluids through a needle in a vein (IV). Some women who are dehydrated may also require electrolytes, such as sodium and magnesium, to help them absorb fluids properly.
Some people may need to stay in the hospital for several days for monitoring.
To prevent dehydration, increase fluid intake until the urine becomes clear or very pale yellow. Consider carrying a water bottle or taking frequent water breaks.
Women who exercise or spend time outside in intense heat should increase their fluid intake even more.
Certain foods can make people more likely to experience dehydration, including caffeinated foods or drinks. It is essential to drink plenty of water when consuming these foods.
Prenatal care plays an essential role in preventing dehydration. Dehydration is often due to an underlying condition, such as a metabolic problem or hyperemesis gravidarum. A doctor can help prevent this condition from causing dehydration.
If a woman has a history of dehydration or a condition that causes dehydration, it is a good idea to talk to a doctor about ways to prevent dehydration from happening.
Typically, dehydration is a temporary inconvenience that can be corrected by drinking more fluids. However, people must take dehydration seriously as it can cause many problems during pregnancy.
Anyone who thinks they might be dehydrated or who have a risk factor for dehydration should discuss their concerns with a doctor.
It is safer to overreact to dehydration than to ignore a problem that could be life-threatening to the baby. Even if a woman is not sure whether their symptoms are serious enough to go to the hospital should err on the side of caution by seeking emergency care.