Postpartum night sweats: why they happen, how long they last and what helps

Postnatal recovery · Updated July 2026 · All articles

Waking up drenched in sweat in the middle of the night is one of those postnatal experiences nobody quite warns you about. You have just fed the baby, changed a nappy, and got back into bed, only to find yourself soaking through your pyjamas. Postpartum night sweats are very common, they do not last forever, and they are not a sign that anything is wrong. Here is why they happen and what you can do to make them more manageable.

Why postpartum night sweats happen: the hormonal cause

During pregnancy, your levels of oestrogen and progesterone are significantly higher than usual. These hormones support the pregnancy and play a role in regulating many body systems, including fluid balance and temperature regulation. After birth, your placenta is delivered and these hormone levels fall sharply and rapidly. For oestrogen in particular, this drop can be dramatic.

One consequence of this hormonal shift is that the hypothalamus, the part of the brain that acts as the body's thermostat, becomes more sensitive. It is the same mechanism that drives hot flushes during menopause, and the experience can feel similar: a sudden wave of heat, followed by heavy sweating as the body tries to cool down. The difference is that postpartum sweating is temporary, because hormone levels gradually stabilise in the weeks and months after birth.

There is a second reason for the sweating. During pregnancy, your body retains a substantial amount of extra fluid: your blood volume expands, you hold more fluid in your tissues, and amniotic fluid adds to the total. After birth, your body works to shed this excess. It does so through several routes, including increased urination and sweating. This process is most intense in the first one to two weeks, which is why early postpartum night sweats can be particularly striking.

Typical timeline: how long does it last?

For most people, postpartum night sweats are most intense in the first two to three weeks after birth and begin to improve significantly by weeks four to six as hormones stabilise and the body sheds the excess fluid it accumulated in pregnancy. By around six weeks, most people notice a marked reduction or complete resolution.

If you are breastfeeding, the timeline can be longer. Breastfeeding suppresses ovulation and keeps oestrogen levels lower than they would otherwise be, which is why the night sweats can persist throughout the breastfeeding period for some people. The sweating is usually not as dramatic as the very early postpartum sweats, but it can continue at a lower level for months. This is a recognised effect of sustained lactation and does not indicate a problem.

People who are formula feeding or who choose not to breastfeed often find that their hormones restabilise more quickly and the sweating resolves sooner.

Practical tips to manage postpartum night sweats

You cannot speed up the hormonal process, but there are several things that help with comfort.

Bedding makes a big difference. Swap thick duvets for lighter alternatives and consider natural fibres such as cotton or bamboo, which breathe better than synthetic materials. Having a light sheet to hand so you can easily adjust your covers during the night helps too. Some people find it useful to put a light towel over their pillow so they can turn it over quickly without disrupting sleep further.

Moisture-wicking nightwear, the kind designed for exercise or for menopause, is much more comfortable than cotton when you are sweating heavily. Several brands make postnatal sleepwear specifically with this in mind. Whatever you choose, loose-fitting and breathable is better than fitted or synthetic.

Keeping the bedroom cool is one of the most effective steps. A fan directed towards the bed, keeping a window open, or lowering the room temperature on a thermostat if you have one all help. If your partner prefers a warmer room, a personal fan on your side of the bed is a reasonable compromise.

Hydration matters too. When you are sweating heavily and also breastfeeding, your fluid needs are higher than usual. Aim to drink water consistently through the day rather than large amounts all at once, and keep a large bottle of water on your bedside table so you can rehydrate easily after a sweaty night and during feeds.

Night sweats versus fever: how to tell the difference

The key question many people ask is whether their postpartum sweating is normal or might be a sign of infection. The distinction is important because some postpartum infections, including mastitis, uterine infection, and wound infection, do cause fever and can make you feel unwell.

Normal postpartum night sweats feel like episodes of heat and sweating without other symptoms. You feel hot and wet but not systemically unwell. Your temperature, if you take it, is within the normal range (below 37.5 degrees C). The sweating passes and you return to feeling relatively normal.

A fever, by contrast, is a temperature of 38 degrees C or above. If you have a high temperature alongside night sweats, or if the sweating is accompanied by shivering or chills, flu-like aching, a very tender breast or breasts, foul-smelling vaginal discharge, increasing pain in the abdomen, or the wound feels hot and red, contact your midwife or GP. You should not assume that all postnatal sweating is hormonal without ruling out an infectious cause, especially in the first two weeks.

Breastfeeding and night sweats: the longer picture

As mentioned, breastfeeding can prolong the period of night sweats. This is because prolactin, the hormone that drives milk production, suppresses the release of the hormones that normally trigger ovulation, keeping oestrogen at a low level for as long as you are nursing. This sustained low oestrogen is beneficial for lactation but means that some of the effects of low oestrogen, including increased heat and sweating, can continue.

This does not mean you should wean your baby to solve the problem. For most people the sweating, while inconvenient, is manageable with the practical steps above. If it is severe and significantly affecting your sleep or wellbeing beyond what you can manage, mention it at your postnatal check so that other causes can be ruled out.

When to seek advice

In most cases, postpartum night sweats are a normal part of recovery and do not need investigation. However, speak to your midwife or GP if your sweating is accompanied by a fever or any of the infection signs described above; if you are sweating heavily during the day as well and feel generally unwell; if the sweating persists and is severe well beyond six weeks and you are not breastfeeding; or if you have concerns about thyroid function, as both postpartum thyroiditis and other thyroid conditions can affect sweating and temperature regulation.

Frequently asked questions

Why do I sweat so much after having a baby?

The main cause is a rapid drop in oestrogen and progesterone after birth. Your body also needs to shed the extra fluid it accumulated during pregnancy, and sweating is one of the ways it does this.

How long do postpartum night sweats last?

For most people, night sweats are worst in the first 2 to 3 weeks and ease off within 4 to 6 weeks. If you are breastfeeding, they may continue longer because oestrogen stays lower while you are nursing.

Do postpartum night sweats affect my milk supply?

Sweating does increase fluid loss, and staying well hydrated supports both your comfort and your milk supply. Aim to drink water consistently through the day and keep a bottle of water nearby for night feeds.

How can I tell if my night sweats are caused by a fever?

Normal postpartum sweats are not accompanied by other symptoms. If you have a temperature of 38 degrees C or above, chills, a headache, tender breasts, or feel unwell beyond just hot and sweaty, this may indicate an infection and you should contact your midwife or GP.

Can postpartum sweating last for months?

It is less common but possible, particularly in people who are breastfeeding, because low oestrogen levels can persist throughout lactation. If sweating is severe or persistent and bothers you, mention it at your postnatal check.

What is the best way to manage postpartum night sweats?

Light, breathable bedding and moisture-wicking nightwear help the most. Keeping the bedroom cool, sleeping with a fan, and staying well hydrated also make a significant difference for most people.

This article is for general information only. Always speak to your midwife, GP, or health visitor if you have concerns about your physical recovery after birth.