Colostrum—the first breast milk, low in volume but rich in immune factors—begins to be made in the breasts a long time before your baby is born. After the birth, a sequence of events initiates milk production whether or not you plan to breastfeed your baby. Although you might not be able to express the colostrum yourself at first, or you might be worried that your milk hasn’t come in or is late; true lactation failure is very rare. There will almost certainly be some milk. However, how much milk depends on getting breastfeeding established early and often and, for a minority of women, whether you have any other potential Reasons for Low Milk Supply. This article discusses the causes for milk coming in late after delivery.
What triggers breast milk to come in?
During pregnancy the placenta has a vital role in generating hormones to develop the milk making factory in the breasts. After the birth of your baby the placenta separates from the uterus and is expelled. This causes a sharp drop in the hormone progesterone which triggers the breasts to start milk production about 32-40 hours after birth.1 The increase from drops of colostrum to plentiful milk is often described as milk coming in. Important hormones that are needed for milk production include prolactin, thyroid hormones, insulin and cortisol (stress hormone). Oxytocin is another hormone that triggers the let-down (milk ejection reflex) of milk at each feed.
When does breast milk come in?
Mothers usually notice their milk coming in two to three days after the birth. Around this time full or engorged breasts replace the small volumes of colostrum that are already present. Milk supply continues to increase as long as the baby—or hand expression or pump—empties the breasts. However if milk removal doesn’t happen, milk production will start to shut down. Anything that affects any of the hormones involved in making milk, the let-down or the milk removal process has the potential to cause a delay in milk coming in, or a low milk supply.
Milk coming in late (delayed onset of lactation)
In a quarter of all mothers, milk can take longer than three days to come in, sometimes taking up to five days2. When milk is very slow to come in it is known as delayed onset of lactation. Just because your milk is late coming in doesn’t necessarily mean you will ultimately have no breast milk or low milk supply but it is a high risk factor. Women with milk that is late arriving are more likely to get stressed about it—which can itself interfere with let-down—leading to a vicious negative cycle of events. If you find yourself in this situation, getting good help from an IBCLC lactation consultant is highly recommended because the sooner you can take action to boost your milk supply and reduce your stress levels, the better 3.if milk removal doesn’t happen, milk production will start to shut downClick To Tweet
No breast milk?
Certain birth practices and some medical conditions can delay milk arriving. It is unlikely that there would be no breast milk at all, as small volumes of colostrum (the first breast milk to appear) will usually have been present for some time before your baby is born. If milk is late arriving it can create a cycle of formula supplementation and a corresponding down regulation of your milk supply leading to more formula and lower milk supply. Possible reasons for no breast milk after delivery are set out below under the headings of birth, breastfeeding management and hormonal issues:
#1 Birth factors
- A very traumatic or stressful birth such as a long labour and/or long pushing stage, or the use of ventouse or forceps will affect levels of stress hormones which can delay milk coming in.4
- Caesarean birth. An emergency caesarean can be very stressful, disrupt optimal feeding patterns and delay milk coming in5 and even planned caesareans can affect breastfeeding due to early delivery before the due date, and without labour, birth hormones that help initiate breastfeeding are missing. One study found babies born by caesarean had a weaker suck.6
- Large amounts of intravenous fluids (IV fluids) used during birth can engorge breasts (due to water retention or oedema) and delay the availability of milk until the engorgement goes down.78
- Synthetic intravenous oxytocin during labour may interfere with the let-down of milk after birth and contribute to engorged breast tissue.9101112
- Pain relief medications given during childbirth have been linked with delayed onset of lactation.13 Any medications given to the mother during labour that make baby sleepy can delay getting breastfeeding off to a good start. One study showed that synthetic oxytocin and fentanyl (a strong pain killer by epidural) decreased the likelihood of a baby sucking during the first hour after birth.14
- Losing a lot of blood e.g. maternal postpartum haemorrhage 1516 or Sheehan’s Syndrome17 may damage the pituitary gland in the brain which controls breastfeeding hormones. Normal limits of blood loss after birth, according to one author, are 1000ml (2 pints) or 500ml after a vaginal birth. 18
- Retained placental fragments can delay milk coming in as progesterone levels remain higher instead of dropping to trigger milk production.
- Nerve damage that affects key nerves involved in milk release, spinal vertebrae that are misaligned can affect milk production and let-down. Body work or manual therapy has helped some mothers.19
- A premature birth or a placenta not working properly. Pregnancy is an important time for mammary gland development. If a baby is born prematurely the breasts may or may not have had enough time to fully develop sufficient glandular (milk-making) tissue and similarly if the placenta wasn’t working optimally (placental insufficiency) the breasts may not have fully developed. Although this can affect the initial milk supply, with careful management, glandular tissue can continue to develop after the birth.
- Heavier babies? One study20 cites heavier birth weight of babies born to first time mothers as a risk factor for delayed onset of lactation.
#2 Breastfeeding management
Separation from baby and a poor start to breastfeeding affects milk coming in because early milk removal in the first hours and days is associated with higher milk supply. Breastfeeding or hand expressing in the first hour after birth is especially important 2122. Without frequent feeds or good milk removal by hand expressing at this time, milk production begins to shut down. See the useful video Successful Breastfeeding Begins Right at Birth by Jane Morton of Stanford University for more information about hand expression in the first hour after birth to stimulate your milk supply. Unrelieved engorgement reduces milk production too.
Factors affecting how efficiently the breasts are drained in the early days are covered in more detail in Reasons for Low Milk Supply under the headings Poor breastfeeding management, Baby’s breastfeeding skills, and Nipple challenges.
#3 Hormonal or medical issues
An imbalance of any of the hormones needed in lactation could affect milk coming in. Conditions that can influence lactation include:
Diabetes or gestational diabetes
Diabetes is a condition where the body doesn’t produce enough insulin (type 1 diabetes) or can’t use it properly (insulin resistance or type 2 diabetes). A temporary form of diabetes in pregnancy is called gestational diabetes. Insulin is an important hormone involved in breast development and milk production and large fluctuations in insulin can affect milk supply.
- Delayed milk. Breast milk may come in later with diabetes.23 With Type 1 diabetes, insulin requirements are adjusted by the body after birth, and this may slow milk coming in by 24 hours24.
- Insulin used to treat gestational diabetes or type 2 diabetes may be associated with delayed milk increase.25
- Less breast growth. Important hormones for development of the “milk factory” in the breast can be lower in pregnancy with type 1 diabetes, possibly affecting milk making tissue. Insulin resistance has been linked to less breast growth and slowing lactation. (Marasco and West, 2020)
- Early deliveries and caesarean birth are more common with diabetes which can both affect breastfeeding.
Not all mothers with diabetes will have problems with milk supply and careful control of blood sugar and insulin levels will help keep a milk supply stable.
The pituitary gland is a small gland in the brain that regulates many hormones including prolactin and oxytocin. If the pituitary gland is not functioning correctly (previous surgery, a pituitary adenoma or Sheehan’s Syndrome following severe blood loss) this could affect lactation.
Gestational ovarian theca lutein cysts
These cysts develop during pregnancy and produce high levels of testosterone which may temporarily suppress milk production after the birth. Studies have shown that these testosterone levels reduce after three to four weeks when the cysts resolve, allowing lactation to often proceed normally. It is recommended that mothers continue to pump during this time to give the best chance for their milk to come in. Diagnosis can be made by blood tests measuring testosterone levels 2627.
Overweight or obese
A high BMI (above 26-30) is a risk factor for delayed lactation282930 and low milk supply associated with a lower prolactin response in the first week after birth31. If the underlying causes of obesity are due to metabolic disorders e.g. polycystic ovary syndrome (PCOS), or hypothyroidism, these are also risk factors for affecting milk supply in their own right. Obese women may also suffer from insulin resistance and diabetes and excessive weight may be linked with poor breast growth in some cases (Marasco and West, 2020).
Polycystic ovary syndrome (PCOS)
PCOS can be associated with delayed onset of lactation see Polycystic Ovary Syndrome and Breastfeeding.
Untreated thyroid disorders can be associated with milk coming in late (Marasco and West, 2020).
Underdeveloped breast tissue or unusual anatomy
If one or both breasts did not develop fully during puberty this may affect the capacity of the breast to make sufficient milk.
Any surgery on the breast or nipples including a breast reduction procedure, a breast lift or breast implants could potentially affect the milk making or glandular tissue in the breast. It may also cause scarring or blocked ducts which might affect the ability of milk to leave the breast.
Older first time mothers
Older first time mothers may be at risk of delayed onset of lactation (Nommsen-Rivers et al, 2010).
Hypertension in pregnancy (pre-eclampsia)
Hypertension during pregnancy (when blood pressure is higher than normal) could be associated with a delay in milk coming in.3233 Difficulties breastfeeding associated with an increased rate of premature birth at this time may also be a factor influencing breastfeeding success.34 See Reasons for Low Milk Supply for more information.
Some medications can have a side effect of decreasing milk production—for example hormonal birth control in the early months. Medications for certain disorders reduce milk supply too, so although milk might be coming in, the supply may be reduced. Some sources cite large doses of vitamin B6 as being associated with affecting milk coming in (Mohrbacher, 2020 p 439).
Until your milk comes in…
Small but regular amounts of colostrum in the first two to three days of life are normally enough for a newborn baby who is kept close to his mother, after all it is biologically normal for milk not to “come in” immediately. Until your milk comes in, latching your baby often (or hand expressing milk for your baby if they are not transferring milk) and holding your baby in skin-to-skin contact will promote the hormones involved in milk production (oxytocin and prolactin) and put your baby in the right place to feed frequently.
What do I do if my milk is late?
If your milk supply doesn’t come in by day three (or longer) your baby could begin to lose excess weight, or become dehydrated or jaundiced. You may also notice the meiconium in your baby’s nappy isn’t changing colour. In any of these situations it is important to get good breastfeeding help quickly, and ensure your baby is well fed. Hand expressing every couple of hours can help stimulate your milk supply and any expressed milk can be fed to your baby (pumping is not usually recommended before your milk has properly come in). Your health professionals will advise you about supplements as donor human milk or formula milk may be needed. It is very important to keep your baby well fed—see Baby Not Gaining Weight. Supplementing your baby doesn’t mean breastfeeding needs to be sacrificed as long as you have the right support.
After the birth, delivery of the placenta triggers milk production in an automatic process and true lactation failure is very rare. The rate of milk volume coming in will depend on getting breastfeeding established early and often, birth practices, and whether the mother has any medical conditions affecting lactation. For a minority of women, other Reasons for Low Milk Supply may be involved.
For ideas to maximise your milk production and ensure your baby is well fed, contact an IBCLC lactation consultant for a tailor made plan for you. In the mean time the ideas in How to Make More Breast Milk will help to both optimise and increase your milk supply.