What to know about fever during pregnancy

Although the average body temperature is usually around 98.6^oF (37^oC), it does fluctuate throughout the day. Minor increases in temperature do not necessarily mean that a person has a fever.

There are five areas of the body that a person can take a temperature measurement from:

• Armpit or forehead: Doctors consider 99.3^oF (37.4^oC) and above a fever.
• Mouth: Doctors consider 100.4^oF (38^oC) and above a fever.
• Rectum or ear: Doctors consider 101^oF (38.3^oC) and above a fever.

Other symptoms of a fever include:

• fatigue
• dizziness
• nausea
• feeling very cold
• alternating between feeling cold and feeling hot
• sweating

Some studies have suggested that fevers during pregnancy may increase the likelihood of congenital irregularities and autism. However, the research so far is inconclusive.

The sections below look at the research into the possible effects of a fever on a developing fetus.

Congenital irregularities

According to the Centers for Disease Control and Prevention (CDC), congenital irregularities affect around 1 in every 33 babies in the United States.

A 2014 review of 46 previous studies found that experiencing a fever during the first trimester of pregnancy may increase the chance of the baby being born with oral clefts, congenital heart defects, and neural tube defects by around 1.5 to 3 times.

However, the results of several of the studies that the researchers reviewed had insufficient evidence to confirm any association between fever and congenital irregularities.

According to the CDC, women who reported experiencing a fever during pregnancy were at least twice as likely to give birth to a baby with neural tube defects. However, there is evidence to suggest that consuming the recommended dosage of folic acid may reduce this likelihood.

According to a 2017 study, however, there is very little evidence to support the idea that maternal fever contributes to the likelihood of congenital irregularities.

Although there appears to be some evidence to suggest that experiencing a fever during pregnancy can increase the chance of congenital irregularities, more recent research appears to contradict this.

Pregnant women or those who wish to become pregnant can talk to a doctor to discuss their individual risk factors if concerned.

Autism

A 2018 analysis found a link between maternal fevers and autism, particularly when the fever occurred during the second trimester.

The same study also found that more frequent fevers further elevated the likelihood. However, the chance of autism in fetuses exposed to fever was lower if the woman took antifever medication during pregnancy.

Pregnancy loss, or miscarriage, occurs in roughly 20% of pregnancies. Fever does not necessarily cause pregnancy loss, but it can be a sign of an infection. Infections are more likely to cause pregnancy loss.

A 2015 study suggests that infections can cause 15% of early and up to 66% of late pregnancy losses.

These figures suggest that even when a woman experiences a fever during pregnancy, it is fairly unlikely that a pregnancy loss will occur.

To treat a fever, it is important for a doctor to diagnose the underlying cause. A doctor will prescribe different medications depending on what is causing the fever.

Antibiotics

If the cause of the fever is a bacterial infection, a doctor may prescribe antibiotics.

Generally, health professionals consider the majority of antibiotics to be safe during pregnancy.

However, only 10% of antibiotic medications "have sufficient data related to safe and effective use" during pregnancy. A doctor should therefore perform a risk assessment and monitor their use.

Antiviral medications

If a pregnant woman notices any symptoms of the flu, they should see a doctor as soon as possible.

They may prescribe antiviral medications, which are most effective when a person takes them within 48 hours of noticing the symptoms.

Over-the-counter medication

Women should not take ibuprofen during pregnancy. According to a 2013 cohort study, ibuprofen use during the second trimester was associated with low birth weight. The use of ibuprofen during the second and third trimester was also associated with asthma.

However, it is possible to take acetaminophen if necessary. This appears to be the safest pain and fever relief medication to use during pregnancy.

That said, pregnant women should only use acetaminophen for as long as it is necessary to reduce the fever.

Home remedies such as resting and drinking lots of fluids may help with the symptoms of a fever and shorten the length of many illnesses.

Folic acid is an important prenatal supplement, as it may decrease the chance of neural tube defects.

A 2017 study of women who had fevers right before pregnancy or very early in pregnancy found that those who consumed under 400 micrograms of folic acid per day had the highest chance of giving birth to a baby with a neural tube defect.

However, because illness in pregnancy can endanger the developing fetus, it is vital to see a healthcare professional before trying any form of home treatment.

Although people cannot always prevent a fever, they may be able to reduce the risk of getting sick in the first place.

Some methods of prevention include:

• getting the flu shot
• frequently washing the hands
• staying away from sick people when possible

Fevers are not usually a sign of a serious illness, but during pregnancy, they may cause complications.

If any of the following symptoms occur during pregnancy, seek medical help:

• severe thirst
• low urine output
• dark urine
• lightheadedness
• severe cramps
• difficulty breathing
• decreased movement of the fetus

It is also important to seek help if the fever does not go down.

If a person is concerned for any other reason, they should contact a doctor.

Fevers are not usually a sign of anything serious, but it is crucial to seek help to identify the underlying cause.

Some research has shown fever during pregnancy as associated with a higher chance of pregnancy loss, autism, or congenital irregularities. However, having a fever does not make these outcomes inevitable.

In fact, research is inconclusive regarding the effects of a fever on pregnancy and the developing fetus. A person can talk to a doctor if they are concerned.