Is it normal to sweat more during pregnancy?

Feeling warmer and sweating more is commonly reported. Blood volume rises about 40 to 50% by late pregnancy, metabolic heat production increases, and more blood flows to the skin, so the body has more heat to release through sweat (Soma-Pillay 2016).

Why do night sweats happen after giving birth?

After delivery, estrogen and progesterone fall sharply and the body sheds fluid retained during pregnancy, partly through sweating. This is linked to night sweats that are usually most intense in the first couple of weeks and then ease.

How long do postpartum night sweats last?

They tend to decline over weeks as hormones return toward baseline. In one longitudinal study, the share of women reporting night sweats fell from 58.6% at 3 days to 15.2% at one month after birth (Ishihara 2020).

When should postpartum sweating be checked by a clinician?

Sweating with fever, chills, a red or tender breast, or feeling unwell can signal infection and should be reviewed promptly. Persistent night sweats beyond the early weeks, or symptoms like a racing heart or unexplained weight change, are also worth discussing.

Is this page medical advice?

No. It summarizes verified figures from published sources. Only a midwife or clinician can determine whether an individual's sweating during or after pregnancy needs evaluation.

Research

Sweating During Pregnancy and After Birth

Many people feel warmer and sweat more during pregnancy and again in the weeks after giving birth. There are clear physiological reasons. In pregnancy, blood (plasma) volume rises by roughly 45%, metabolic heat production increases, and blood flow to the skin goes up, so the body has more heat to shed. After delivery, estrogen and progesterone fall steeply and the body offloads retained fluid, a combination linked to night sweats. In one prospective study, 35% of women reported nighttime hot flashes during pregnancy and 29% reported them after delivery (Thurston 2013). This page traces each figure to its source. It is general education, not medical advice.

By the Sweat Explained Editorial Team · Published 2026-07-20 · Last reviewed 2026-07-20 · Educational information, not medical advice.

Key statistics at a glance

35%
of women reported nighttime hot flashes during pregnancy in a prospective study of nearly 450 women
Thurston 2013 (Fertil Steril)
29%
reported nighttime hot flashes in the year after delivery in the same cohort
Thurston 2013 (Fertil Steril)
~45%
rise in blood (plasma) volume by late pregnancy, raising skin blood flow and the heat the body must lose
Soma-Pillay 2016
58.6% to 15.2%
share of postpartum women reporting night sweats, falling from 3 days to 1 month after birth
Ishihara 2020

Why pregnancy changes how you sweat

Pregnancy reshapes the circulation and metabolism in ways that make heat easier to feel and harder to hold in. Blood (plasma) volume expands by roughly 40 to 50% by the third trimester, cardiac output rises, and blood flow to the skin increases (Soma-Pillay 2016). Resting metabolic rate and oxygen use also climb to support the growing fetus, so the body generates more heat at rest than before.

Sweating is the body's main way to shed that extra heat. When more warm blood reaches the skin, the eccrine sweat glands are recruited more readily, which is why many pregnant people report feeling flushed, warm, and sweaty, especially later in pregnancy and at night. Higher progesterone, which is associated with a small rise in body temperature, adds to the sense of running warm. None of this is a sign that something is wrong; it is the expected consequence of a larger blood volume and a higher heat load.

What the research measured

Hot flashes and night sweats are usually filed under menopause, but a prospective study followed women from pregnancy into the year after birth and found the same symptoms are common in reproductive life too. Thurston and colleagues (2013) assessed nearly 450 women at weeks 20, 30, and 36 of pregnancy and again at 2, 12, 26, and 52 weeks after delivery. 35% reported nighttime hot flashes during pregnancy and 29% reported them after delivery.

The predictors overlapped with those seen at menopause: younger age, higher pre-pregnancy body mass index, and higher depressive symptoms were each associated with reporting nighttime hot flashes. The authors framed vasomotor symptoms as a feature of large hormonal shifts in general, not menopause specifically. Because these were self-reported symptoms in one cohort, the exact percentages should be read as a snapshot rather than a fixed rate for everyone.

Reported figures across the perinatal period

Prevalence depends on how sweating is defined and when it is measured. Postpartum night sweats are reported most often in the first days and weeks and decline as hormones settle.

Reported prevalence of hot flashes and night sweats around pregnancy and birth
Timepoint	Finding	Source
During pregnancy	35% reported nighttime hot flashes	Thurston 2013
After delivery (over the year)	29% reported nighttime hot flashes	Thurston 2013
3 days postpartum	58.6% reported night sweats	Ishihara 2020
2 weeks postpartum	33.1% reported night sweats	Ishihara 2020
1 month postpartum	15.2% reported night sweats	Ishihara 2020

The two studies used different populations and definitions (nighttime hot flashes vs night sweats), so their numbers describe related but not identical experiences.

After birth: the postpartum sweat

The days and weeks after delivery bring one of the fastest hormonal changes in adult life. Estrogen and progesterone, which had risen through pregnancy, drop sharply once the placenta is delivered. At the same time, the body sheds the extra fluid it carried during pregnancy, partly through increased urination and partly through sweating. Together these can produce drenching night sweats, most noticeably in the first couple of weeks.

In a longitudinal Japanese study of postpartum women, the share reporting night sweats fell from 58.6% at 3 days after birth to 33.1% at 2 weeks and 15.2% at one month, tracking the return of hormone levels toward baseline (Ishihara 2020). Breastfeeding, which involves the hormones oxytocin and prolactin, and disrupted sleep can also play a role in how warm and sweaty the early postpartum period feels.

Usually expected, and what is worth mentioning

Perinatal sweating is common and usually settles on its own. A few patterns are worth raising with a clinician, not because sweating itself is dangerous, but because it can occasionally sit alongside something treatable:

Feeling warm, flushed, or sweaty during pregnancy and drenching night sweats in the first weeks after birth are commonly reported and typically ease as hormones and fluid balance settle.
Sweating accompanied by fever, chills, a tender or red breast, or feeling unwell can point to an infection and deserves prompt review.
A racing heart, tremor, unexplained weight change, or heat intolerance out of proportion to the situation are worth mentioning, since thyroid activity shifts around pregnancy.
Night sweats that persist well beyond the early postpartum weeks, or that come with other new symptoms, are reasonable to discuss rather than simply endure.

How to read these numbers

The reliable message is directional. Pregnancy raises blood volume, metabolic heat, and skin blood flow, so more sweating is physiologically expected; after birth, a rapid fall in reproductive hormones and the offloading of retained fluid are linked to night sweats that usually fade over weeks. The specific percentages, roughly a third during pregnancy and a smaller share persisting postpartum, come from individual cohorts and vary with how questions are asked.

This page describes common physiological changes, not a diagnosis. Sweating in pregnancy or after birth that is severe, one-sided, or paired with fever or other new symptoms is worth discussing with a midwife or clinician, who can tell an expected change from one that needs attention.

Methodology and limitations

This page draws on a prospective cohort study of vasomotor symptoms across pregnancy and the postpartum year (Thurston et al., Fertil Steril 2013, n approximately 450), a longitudinal study of postpartum night sweats and hot flashes in Japan (Ishihara et al., Int J Nurs Midwifery 2020), and a peer-reviewed review of the physiological changes of pregnancy for the plasma-volume and circulatory figures (Soma-Pillay et al., Cardiovasc J Afr 2016). Each figure was traced to its source.

Limitations: the prevalence figures are self-reported in specific cohorts and depend on definitions (nighttime hot flashes versus night sweats) and timing, so they should not be merged into a single number. The Japanese cohort was small and its authors note limited generalizability. Associations with body mass index, age, and mood do not establish cause. The plasma-volume and metabolic figures are population averages, not individual guarantees. Nothing here is a diagnosis or medical advice; sweating with fever or other new symptoms should be reviewed by a clinician.

Frequently asked questions

Is it normal to sweat more during pregnancy?: Feeling warmer and sweating more is commonly reported. Blood volume rises about 40 to 50% by late pregnancy, metabolic heat production increases, and more blood flows to the skin, so the body has more heat to release through sweat (Soma-Pillay 2016).
How common are hot flashes and night sweats in pregnancy?: More common than many expect. In a prospective study of nearly 450 women, 35% reported nighttime hot flashes during pregnancy and 29% reported them after delivery, with predictors similar to those seen at menopause (Thurston 2013).
Why do night sweats happen after giving birth?: After delivery, estrogen and progesterone fall sharply and the body sheds fluid retained during pregnancy, partly through sweating. This is linked to night sweats that are usually most intense in the first couple of weeks and then ease.
How long do postpartum night sweats last?: They tend to decline over weeks as hormones return toward baseline. In one longitudinal study, the share of women reporting night sweats fell from 58.6% at 3 days to 15.2% at one month after birth (Ishihara 2020).
When should postpartum sweating be checked by a clinician?: Sweating with fever, chills, a red or tender breast, or feeling unwell can signal infection and should be reviewed promptly. Persistent night sweats beyond the early weeks, or symptoms like a racing heart or unexplained weight change, are also worth discussing.
Is this page medical advice?: No. It summarizes verified figures from published sources. Only a midwife or clinician can determine whether an individual's sweating during or after pregnancy needs evaluation.

Sources

Primary peer-reviewed studies and official sources first, then reviews and institutional framing (secondary).

Thurston RC, Luther JF, Wisniewski SR, Eng H, Wisner KL. Prospective evaluation of nighttime hot flashes during pregnancy and postpartum. Fertil Steril. 2013;100(6):1667-1672. 35% reported nighttime hot flashes during pregnancy and 29% after delivery. Full text
Ishihara R, Nagamine K, Haku M, Uemura H, Matsuura Y, Yasui T. Prevalence and factors related to hot flashes and night sweats in postpartum women in Japan. Int J Nurs Midwifery. 2020. Night sweats reported by 58.6% at 3 days, 33.1% at 2 weeks, and 15.2% at 1 month postpartum. Journal
Soma-Pillay P, Nelson-Piercy C, Tolppanen H, Mebazaa A. Physiological changes in pregnancy. Cardiovasc J Afr. 2016;27(2):89-94. Plasma volume rises about 40 to 50% and cardiac output increases in pregnancy. (secondary) Full text
Sanghavi M, Rutherford JD. Cardiovascular physiology of pregnancy. Circulation. 2014;130(12):1003-1008. Reviews blood volume, cardiac output, and heat-load changes across pregnancy. (secondary) Journal

How to cite this page

Sweat Explained. Sweating During Pregnancy and After Birth. Published 2026-07-20; last reviewed 2026-07-20. Available at: https://sweatexplained.com/research/pregnancy-and-sweating

Please cite the original studies for the underlying figures. Journalists are welcome to link to this page; the charts are original renderings of the cited data.