A slight shift in core body temperature is one of the many physiological changes that occur during pregnancy. The body’s ability to manage heat is altered, moving the internal thermostat to a slightly higher baseline. Monitoring this temperature is a simple yet effective part of prenatal self-care, helping to distinguish between a normal, expected increase and a potentially concerning fever.
The Underlying Causes of Increased Body Heat
The feeling of being warmer than usual is a common experience during pregnancy, largely due to hormonal changes. The hormone progesterone, produced to maintain the pregnancy, acts as a thermogenic agent. This causes the basal body temperature to remain elevated, resulting in a subtle but sustained increase of about 0.2 degrees Fahrenheit above the pre-pregnancy baseline. This elevation is also a result of the body’s increased workload; the metabolic rate accelerates to support fetal development and generates more internal heat, while increased blood volume and cardiac output cause circulating blood to move closer to the skin’s surface, aiding heat dissipation and resulting in the sensation of feeling flushed or hotter. This subtle, non-pathological temperature change should not be mistaken for a fever.
Identifying Fevers and Dangerous Temperature Thresholds
While a minor temperature increase is normal, a true fever is defined as an oral temperature of 100.4 degrees Fahrenheit (38 degrees Celsius) or higher. A temperature at or above this threshold indicates an underlying infection or illness that requires medical attention. It is the sustained elevation of the core body temperature, rather than temporary warmth, that raises concern.
A prolonged or high fever, particularly one exceeding 103 degrees Fahrenheit, can pose risks to the developing fetus, especially during the first trimester when major organs are forming. Exposure to hyperthermia during this early stage is linked to an increased risk of specific birth defects, such as neural tube defects, like spina bifida. High temperatures may also be associated with complications, including an increased risk of miscarriage or preterm labor later in the pregnancy. If a temperature reaches 100.4 degrees Fahrenheit, contact a healthcare provider immediately. Acetaminophen is the preferred and safest medication for reducing a fever, and non-pharmacological methods like cool compresses and hydration can also help.
Managing External Heat Exposure and Safe Cooling Methods
Preventing the core body temperature from rising due to environmental factors is important for pregnant individuals. Since the body is already working harder to dissipate internal heat, it is more susceptible to heat exhaustion and heat stroke. The maternal core temperature should not exceed 102 degrees Fahrenheit due to external sources. Activities that prevent effective cooling, such as using hot tubs, saunas, or steam rooms, should be limited or avoided. Exposure to water temperatures above 102 degrees Fahrenheit can raise the core temperature too quickly, so experts advise limiting time in a hot tub or sauna to less than 10 minutes.
To manage external heat, pregnant people should adopt several cooling strategies:
- Wear loose-fitting, light-colored clothing made from breathable fabrics.
- Stay well-hydrated by drinking ample water.
- Schedule outdoor exercise for cooler parts of the day, such as the early morning or evening.
- Seek air-conditioned spaces or shade during peak heat hours.
- Take a cool shower or bath to quickly lower the body’s surface temperature.