Reasons for Low Milk Supply

There are many possible reasons for a low milk supply, from infrequent feeds and using formula supplements to a pre-existing condition in a mother’s medical history or insufficient glandular tissue. For most women, a low milk supply can be easily prevented or corrected with the right information and timely support from an IBCLC lactation consultant. However for a small minority of women medical factors may mean that exclusive breastfeeding may not always be possible.

This article

This article looks at some of the reasons for an absent or very low milk supply. For ideas to increase milk volume see How to Make More Breast Milk and to gauge how much milk your baby is getting see Is My Baby Getting Enough Milk?

Nine reasons for low milk supply

Reasons for low milk supply often include a combination of things—from poor breastfeeding management, to baby related factors such as a poor suck, or mom related factors such as insufficient glandular tissue. Here are nine frequent reasons:

#1 Breast milk coming in late (delayed onset of lactation)

Delayed lactation is a risk factor for low milk supply particularly if the mother doesn’t have the correct support and information along with personal determination. Check through the ideas in No Breast Milk After Delivery for several potential reasons for milk coming in late.

#2 Poor breastfeeding management

One of the biggest risk factors for low milk supply is not enough milk removal in the first few days (and nights!) after birth. And the following weeks are important too. Poor milk removal might be due to a baby not sucking well (#3) or poor breastfeeding management e.g. delaying feeds by using a pacifier, being separated from your baby after the birth, restricting the length of feeds, scheduling feeds, keeping to one breast per feed or leaving a sleepy baby to sleep. If milk removal doesn’t happen, milk production will start to shut down.

Supplemental feeds interfere with milk production

Topping up with formula can interfere with breastfeeding too. For every supplemental feed of formula you give your baby today your breasts won’t make that amount of milk tomorrow. This can quickly lead to a downward spiral of more and more supplements and less and less breast milk until you have a really low milk supply. With good support, formula supplements are seldom needed. However there may be situations where your baby does need supplements of human donor milk or formula e.g. if he is very jaundiced or your milk supply is very late to come in after delivery. Or later on, if your milk supply has dwindled and your baby isn’t gaining any weight.  Until you can get help with breastfeeding, hand expressing or pumping every couple of hours or more can help protect your milk supply and provide breast milk for top ups.

Mother breastfeeds skin to skin

#3 Baby not transferring milk properly

A baby not removing milk from the breasts properly will have the same end result as poor breastfeeding management—low milk supply. Just because a baby is in position and seems to be latched on to the breast every two hours or ‘all the time’, doesn’t necessarily mean that baby is drinking and swallowing. Good clues for milk transfer are discussed in Is My Baby Getting Enough Milk? and include looking and listening for swallows of colostrum, watching the jaw for active sucking and monitoring the amount of baby poop. Poor milk transfer could be due to baby related factors such as a poor suck, or difficulties with mother’s anatomy.

Poor suck

Causes for a poor suck include poor latch, poor tongue function or tongue tie, prematurity or being small for dates, being in pain or having a headache from a traumatic birth, cardiac or respiratory problems, low or high muscle tone, anatomical variations such as a tiny jaw (micrognathia), cleft palate, or any illness affecting the baby e.g. severe jaundiceSore nipples for mother usually indicate a problem with latch which can interfere with driving the milk supply correctly. Medications used during the birth can make for a sleepy baby who may be too tired to suck properly.

Flat, inverted or unusual nipples, or unusual anatomy

Unusual nipples such as very flat or inverted nipples, very large, very long or differently shaped e.g. double nipples or with a skin tag can affect how easily a baby latches. Nipple piercing may have led to scarring or closure of nipple pores which can block milk flow. A mismatch in breast to mouth fit or very tight inelastic breast tissue can be an issue until baby grows. A mother and baby can often overcome any difficulties in anatomy with the right skilled help.

#4 Insufficient glandular tissue

When milk truly doesn’t seem to come in after birth (rather than it started to come in but was suppressed by poor management or other medical issues) it may be due to insufficient glandular tissue (IGT). Other names for this include primary lactation failure, lactation insufficiency, delayed or failed lactogenesis 2, or hypoplastic breasts. IGT is rare and normally there might be some clues in your medical history or physical characteristics. Indicators might include having had breast reduction or augmentation surgery (#5), hormone or endocrine issues (#6), very small and widely spaced breasts, tubular shaped breasts, if one breast is markedly different to the other, if your breasts hadn’t enlarged and been tender during puberty or pregnancy or if there wasn’t a feeling of fullness after the birth 1.

Further reading

For more information see Breastfeeding with Hypoplasia Insufficient Glandular Tissue, Breastfeeding Today, by Diana Cassar-Uhl. Even if you do have a low milk supply you can still have a breastfeeding experience by supplementing at the breast with the help of a supplemental nursing system. Ruth Cumming shares her story of breastfeeding with IGT here Making the Most of What We Have.

#5 Breast surgery or trauma

Any previous surgery to the chest area has the potential to damage important nerve pathways and ducts and compromise glandular tissue in the breast. Examples include breast reduction or augmentation procedures (breast implants), lumpectomy or biopsy, incision and drainage of an abscess, a history of trauma to the chest area including having a chest drain as a premature baby, or a history of radiation or burns to the breast. A breast infection could cause a lower supply in the affected breast. Anything affecting breast development during puberty, spinal cord injuries or any surgery affecting the brain and pituitary gland can also affect lactation.

#6 Hormonal or endocrine disorders

If a mother has an underlying hormonal imbalance or needed fertility treatment to get pregnant this could flag an issue with milk production. Possibilities include:

  • Polycystic ovary syndrome (PCOS) has an association with low milk supply for some mothers. See Polycystic Ovary Syndrome and Breastfeeding for further information.
  • Luteal phase defect is associated with insufficient progesterone in the luteal phase (after ovulation) of the menstrual cycle and is associated with IGT 2
  • Thyroid issues may affect both oxytocin and prolactin (breastfeeding hormones) and, if not diagnosed and addressed, could be a factor for low milk supply.
  • Diabetes or gestational diabetes is a risk factor for low milk supply or milk coming in a day or so later than usual for some mothers. Monitoring blood sugar and insulin levels carefully can help to keep the milk supply stable.
  • Pregnancy while breastfeeding can cause a milk supply to drop.
  • Gestational ovarian theca lutein cysts (see No Breast Milk After Delivery for further information).
  • Other health conditions may be related to low milk supply such as autoimmune disease including lupus, kidney failure, or hypopituitarism.
  • Being overweight or obese with a BMI greater than 26 is a risk factor for low milk supply.

#7 Medications, hormonal contraception, herbs, vitamins and minerals

Certain medications and hormonal birth control may reduce milk supply. Individual medications can be checked in the resources listed in Medications and Breastfeeding.

  • Hormonal birth control including the pill, contraceptive implants or hormone impregnated intrauterine devices can affect milk supply in some cases, see Can You Get Pregnant While Breastfeeding? for more information. Postpartum tubal ligation (having ones tubes tied) has also been linked with low milk supply for some mothers 34.
  • Herbs. Some herbs e.g. sage, parsley, or mint can reduce a milk supply if taken in excess.
  • Too much Vitamin B6 is linked with low milk supply for some mothers.
  • Having low iron levels can impact on milk supply; supplemental iron from your doctor and iron rich foods will help to replenish your iron stores 5.
  • Hypertension during pregnancy (when blood pressure is higher than normal) is a risk factor for low milk supply, either via affecting breast development during pregnancy—because hypertension may affect the placenta—or some of the drugs used in treatments may suppress lactation67. High blood pressure that starts during a pregnancy after 20 weeks gestation is called gestational hypertension which encompasses pregnancy induced hypertension (PIH) or preeclampsia. HELLP syndrome (NHS link) is a severe form of this.

#8 Being half hearted from the start

Planning to mix feed or “try” to breastfeed, doubting whether breast milk can satisfy a baby, being embarrassed, having a lack of information and support, and not getting early help for problems—are all possibilities for “low milk supply” even when sometimes it isn’t a low supply at all. Having mixed feelings about breastfeeding can lead to reliance on formula and a self fulfilling prophecy when milk supply drops (see #2 above).

#9 Other factors

Other factors that can influence low milk supply include;

What can I do if I have low milk supply?

Find good support

Finding a good IBCLC lactation consultant to support you to maximise your milk production will be invaluable. They will be able to share good breastfeeding tips, help you with positioning, and latching and make a specially tailored plan for you and your baby. See Baby Not Gaining Weight, How to Increase Milk Supply When Pumping and How to Make More Breast Milk for more reading.

Supplementing at the breast

For mothers who need to supplement additional milk, supplementing at the breast with a commercial or Home Made Supplemental Nursing System can help maximise supply, preserve the breastfeeding experience and provide more time in skin-to-skin contact—with all its many benefits.


There are many possible reasons that could contribute to a low milk supply. Knowing the reasons for a milk supply coming in late, or never seeming to get established can help prevent it happening in the first place, or prevent it with a subsequent baby. It will also provide an explanation for the mother who is grieving for her lost breastfeeding experience. With the right help and information, breastfeeding works well and the number of mothers who truly have low milk supply are a small minority.