It's normal to have a slightly higher body temperature when you're pregnant, although this varies among women. However, if you notice your body temperature is abnormally high or low, it could be a sign of an illness that could harm you and your baby. See your doctor if you're concerned, especially if you have other symptoms. In general, it's more dangerous to be too hot than too cold. Make sure you take extra care to avoid overheating during hot weather or exercise.
Basal Body Temperature and Ovulation
A slight rise in body temperature can be one of the first signs you're pregnant. The average basal, or resting, body temperature is 98.6 degrees F, but this varies during your menstrual cycle. After ovulation, your body releases progesterone, causing your temperature to rise by roughly 1 degree. When you're pregnant, your body continues to release progesterone, causing your temperature to remain elevated. Your metabolic rate increases, generating extra heat. For consistency, it's best to measure your basal temperature as soon as you wake up, using an oral or rectal thermometer.
Changes In Temperature During Pregnancy
According to the University of Tennessee's Center for Physical Activity and Health, your temperature is likely to fall gradually during pregnancy. It usually falls by around 0.5 degrees during the first trimester, and 0.2 degrees each month afterward. Increased blood flow to the skin helps reduce your temperature to your normal level by the time you give birth.
Abnormally High Temperature
If your temperature is 101 or above during pregnancy, this can be a concern. The most common cause is a fever due to illness. Studies have found an increased risk of birth defects if mothers have abnormally high temperatures early in pregnancy. There's some evidence it could lead to an increased risk of heart defects, abdominal wall defects, oral clefts and miscarriage, but results are not conclusive. Sepsis, a serious condition and one of the most common causes of maternal death, can result in high or low temperatures, as well as changes in skin color, vomiting and difficulty breathing. If you think you have a fever or sepsis, seek immediate medical attention.
Abnormally Low Temperature
Low temperatures usually are less concerning than high ones, but if your temperature falls below 95, talk to your doctor, as it can be a sign of a serious condition. You might have anemia, which is caused by an iron deficiency and is common in pregnant women. Other symptoms include dizziness, fatigues and headaches. If you get the flu, it can lead to pneumonia, which is particularly dangerous for pregnant women. You need immediate treatment to avoid birth complications.
The Organization of Teratology Information Services advises pregnant women not to become overheated and to limit use of hot tubs. Never let your core body temperature rise above 102. A warm bath is a safer way to relax. When exercising, wear loose, cool clothing and avoid strenuous activity in hot, humid weather. Make sure you drink plenty of water to stay hydrated.
- MayoClinic.com: Getting Pregnant: Symptoms of Pregnancy; February 2011
- University of Tennessee Center for Physical Activity and Health: Body Changes During Pregnancy;
- Organization of Teratology Information Specialists; Hyperthermia and Pregnancy; August 2010
- PDR Health: Pneumonia in Adults Treatment; 2011
- American Congress of Obstretricians and Gynecologists: Exercise During Pregnancy; June 2003
- World Health Organisation: Maternal Mortality; August 2008
- Medline Plus: Sepsis; September 2010