Feeling cold or experiencing chills during pregnancy is a common sensation. The body undergoes a profound transformation to support the developing fetus, and these changes dramatically affect the body’s temperature regulation system. This altered thermal sensitivity is a direct consequence of shifting hormone levels, adjustments to circulation, and changes in the body’s overall metabolism.
The Primary Hormonal and Metabolic Drivers
The reproductive hormone progesterone significantly influences the body’s internal thermostat, located in the hypothalamus. Progesterone has a thermogenic effect, promoting heat production and conservation, which leads to a slightly elevated basal body temperature. While this hormone maintains the uterine lining, its effect on the hypothalamus can sometimes lower the body’s perceived temperature set point.
When the body’s set point is shifted downward, a normal body temperature may feel like a chill, prompting the sensation of coldness. The basal metabolic rate (BMR) also increases substantially during pregnancy to support the growth of the fetus and associated tissues. Although an increased BMR generates more heat, the resulting fluctuations in heat distribution can contribute to feeling cold.
Circulatory Changes and Anemia
A significant contributor to cold sensations is the dramatic increase in blood volume, which can increase by 30% to 50%. While the total volume of blood fluid increases substantially, the number of red blood cells does not increase at the same rate. This leads to hemodilution or physiological anemia, which lowers the concentration of oxygen-carrying red blood cells and can cause fatigue and coldness.
The body prioritizes blood flow to the uterus and core organs, shunting blood away from the extremities. This altered peripheral circulation is why cold hands and feet are a common complaint. Iron deficiency anemia, the most common type of anemia in pregnancy, impairs the blood’s ability to transport oxygen efficiently, further exacerbating the cold sensation. Healthcare providers routinely test iron levels to monitor for this condition.
When Coldness Signals a Problem
While feeling chilly is often a normal physiological response, coldness accompanied by other symptoms can signal a medical issue requiring professional attention. The most immediate concern is a persistent cold feeling or chills that occur alongside an elevated temperature. A fever, defined as 100.4°F (38°C) or higher, may indicate an underlying infection, such as a urinary tract infection or the flu.
Any fever during pregnancy should be reported to a healthcare provider immediately, as infections pose risks to both the pregnant person and the fetus. Persistent, severe coldness, especially when accompanied by extreme fatigue, dry skin, or unexplained weight gain, may also warrant a check for undiagnosed hypothyroidism. Thyroid imbalances affect the body’s metabolism and temperature regulation, requiring proper blood testing for diagnosis.
Strategies for Managing Persistent Coldness
Simple adjustments to daily habits can effectively manage the discomfort of feeling persistently cold. Adopting a layered approach to clothing allows for easy thermal regulation as the body’s temperature fluctuates throughout the day. Wearing multiple thin layers, such as a base layer, a middle layer, and an outer layer, traps heat more efficiently than a single thick garment.
Maintaining adequate hydration is important, as proper fluid balance supports increased blood volume and circulation. Consuming warm liquids, such as herbal teas or broths, can provide internal warmth. If anemia has been diagnosed, increasing the intake of iron-rich foods, like lean red meat, poultry, and beans, can support red blood cell production. Light, safe physical activity, such as walking, can temporarily boost circulation and help warm the extremities.