Expressing Colostrum Antenatally

Small volumes of colostrum (the first breast milk) are usually enough for most newborn babies until their mothers’ milk arrives in larger volume on the second or third day of life. Sometimes however, there are situations where a baby may need additional milk feeds before his mother’s milk comes in. For example a baby born to a diabetic mother might be born with low blood sugar, and need food quickly to address this. Expressing and storing colostrum antenatally (before birth) means the perfect food will be available if needed, and avoids having to use infant formula. Avoiding formula where possible is desirable as it is an industrially made substance missing the important protective factors, hormones and friendly bacteria that a newborn baby needs at birth.

This article

This article looks at whether expressing colostrum during late pregnancy is safe, what the potential benefits could be and answers frequently asked questions.

Antenatal expression of colostrum

Other names used for expressing colostrum before birth include antenatal expression, harvesting colostrum and antenatal banking of colostrum. The technique involves hand expressing and collecting drops of colostrum during late pregnancy. Colostrum is particularly valuable to a newborn baby, it is low in volume but each drop is rich in antibodies and concentrated nutrition.

Is antenatal expression safe?

Several NHS (National Health Service) foundation trusts in the UK advocate antenatal expression (referenced below), and breastfeeding charities offer information on the subject.12 However, in the literature, there are mixed opinions about the safety of harvesting colostrum in pregnancy. The main safety issue is that nipple stimulation releases oxytocin, a hormone that causes the uterus to contract in labour. There is a concern therefore that antenatal expression could potentially trigger premature labour resulting in complications from an early birth. Those who advocate antenatal expression usually recommend doing so after 36‑37 weeks gestation—as long as there are no risk factors present for premature birth (see below), and as long as the mother’s health care professional has no concerns.

What does research say?

A recent study, known as the DAME study (Diabetes and Antenatal Milk Expressing), looked at the safety of antenatal expression amongst over 600 women with diabetes in pregnancy and found:

There is no harm in advising women with diabetes in pregnancy at low risk of complications to express breastmilk from 36 weeks gestation.

Another study in diabetic women found that learning to express in the last month of pregnancy can result in less formula use after birth.3

Previous to the studies above however, several authors and researchers expressed concerns about the safety of expressing colostrum in pregnancy. Lawrence and Lawrence4 say antenatal expression is a controversial procedure which could cause premature labour and occasionally antenatal mastitis, and risks outweigh benefits. Soltani and Scott5 found a higher rate of admission of babies to the special care baby unit (SCBU) when mothers expressed antenatally. And several other studies concluded that more research was needed before deciding whether antenatal expression was safe. 678

Antenatal expressing and the uterus

Feldman and Singh explain why oxytocin release from antenatal expression would be unlikely to cause labour contractions in the early antenatal period—because there are considerably fewer sites for oxytocin to be absorbed by the uterus (oxytocin receptors) before a mother’s due date. This may also be why intravenous oxytocin used to induce labour will not always work if the uterus isn’t ready. Another hormone, progesterone, also has a tight control on when birth will start, and the amount of nipple stimulation needed to trigger labour is thought to be much higher than that involved in antenatal expression.910

Breastfeeding through pregnancy

Nipple stimulation due to a mother continuing to breastfeed a sibling during late pregnancy is not thought to trigger premature labour in a normal, low risk pregnancy 1112 and is likely to be at a higher frequency than antenatal expression. For more reading see Can You Get Pregnant While Breastfeeding?

When can breast or nipple stimulation trigger labour?

Rebecca Dekker discusses the research regarding breast or nipple stimulation triggering labour in Natural Labor Induction Series: Breast Stimulation. Dekker concludes that nipple stimulation can help induce labour at term, and can also help ripen the cervix, reduce cesareans and reduce postpartum haemorrhage. She shares that although several large randomised trials have not found any adverse effects, there have been case studies where nipple stimulation has caused uterine hyperstimulation which could be harmful to the foetus, so caution and monitoring are advised. Recommendations are to only stimulate one breast at a time, have rest intervals and mothers with high risk pregnancies are not advised to use nipple stimulation to trigger labour.

What are the benefits of antenatal expression?

Collecting colostrum before birth can:

  • Provide a human milk supplement for after birth. Stored colostrum provides the perfect complete food a baby needs if for any reason he has difficulty breastfeeding or needs a supplement before his mother’s milk has “come in”.
  • Prevent the need for industrially made formula and its associated disadvantages13
  • Help establish a full milk supply more quickly and get breastfeeding off to a good start 14
  • Increase a mother’s confidence in hand expressing.15 Even if the drops of colostrum are not saved, once the technique of hand expression is learned, a mother can start hand expressing straight after the birth if her baby isn’t able to latch immediately.

Why is colostrum so important?

  • Colostrum raises a baby’s blood sugars better than formula16
  • Colostrum acts as a laxative and helps to pass meconium quickly which helps prevent jaundice17
  • Colostrum helps keep baby hydrated
  • Colostrum helps the immune system develop and contains antibodies to protect baby
  • Colostrum helps protect babies against developing diabetes. Formula can trigger diabetes in some babies and avoiding formula milk for the first six months can help protect against this 1819
  • Colostrum protects against allergies. Colostrum helps the digestive system develop normally, introduces friendly bacteria to colonise the gut and avoids exposure to cows’ milk formula which can trigger cows’ milk protein allergy in susceptible children, particularly those with a family intolerance to dairy. 20

mother in hospital holding baby skin-to-skin

In what situations might expressing colostrum be useful?

Antenatal expression of colostrum is often suggested for mothers with diabetes or gestational diabetes however there are other situations where it may be useful too. Mid Essex Hospital Services summarise who might find it useful in their patient information leaflet:

  • Women with diabetes in pregnancy (pre-existing or gestational);
  • Infants diagnosed during the antenatal period with cleft lip and/or palate;
  • Infants diagnosed with congenital conditions;
  • Mothers having an elective caesarean section;
  • Infants diagnosed as small for gestational age;
  • Women with breast hypoplasia;
  • Women with hormonal disorder (e.g. Polycystic ovary syndrome);
  • Women who have had breast surgery;
  • Women with multiple sclerosis;
  • Strong family history of dairy intolerance or inflammatory bowel disease;
  • Mothers taking beta blockers (e.g. labetalol);
  • Mothers with a BMI of 37 or above;
  • Mothers expecting twins or triplets.

Royal Berkshire NHS include mothers who have any medical condition where challenges are anticipated, if a mother will be having a planned caesarean or labour will be induced or has a history of metabolic disorders.21

When is antenatal expression not recommended?

Antenatal expression of colostrum is not usually recommended before 36-37 weeks gestation, nor if you have cervical incompetence or a cervical stitch in place, are expecting more than one baby (multiple pregnancy) or have a history of threatened or actual premature labour.2223

When can I express colostrum?

Colostrum is produced in the breast quite early in pregnancy, some mothers may notice they leak small amounts from the second trimester.24 However, it is usually recommended to begin harvesting colostrum much closer to baby’s due date—from around 37 weeks gestation. Mothers are advised to discuss their start date with their health care professionals in case they have any risk factors that mean antenatal expression should be avoided (see above). If a mother notices cramping pains during expressing, she should stop expressing and rest and discuss this with her health care professional.25

A small syringe of colostrum
Drops of expressed colostrum can be collected with a blunt ended sterile syringe

How do I express colostrum?

Hand expressing rather than pumping is the best way to collect colostrum as there will only be drops to collect at first and colostrum is thicker and stickier than mature breast milk. Labour is also more likely to be induced with high frequency pumping than gentle hand expression (Singh, 2009) and pumping is not recommended. The drops of expressed colostrum can be collected with a blunt ended sterile syringe or expressed onto a spoon or into a small cup and then drawn into a syringe for storage (Cox, 2006).

  • For information and videos on techniques for hand expressing colostrum see Hand Expressing Breast Milk
  • For an illustrated step by step guide to collecting and saving colostrum see Colostrum Harvesting ( scroll down to “How to Harvest Colostrum—Antenatal Expressing of Colostrum”.

How often can I express colostrum?

Information varies considerably from once a day26 to at least four times a day27. Mothers in the DAME study expressed twice per day. Your own NHS trust may have their own recommendations.

Some women find they can’t express colostrum before birth, this doesn’t mean they will have difficulty with breast milk production after birth.

How do I store colostrum?

The small syringes used to collect colostrum can be frozen with the colostrum inside and thawed later as needed. After the birth, the syringe can be used to drip the colostrum into baby’s mouth. Maternity hospitals may be able to provide sterile syringes, or medical suppliers online provide individually wrapped small sterile syringes with or without caps e.g. 1ml, 2.5ml or 5ml. Mid Essex Hospital services recommend the following storage times:

You can collect your colostrum 2-3 times on the same day and store in the same syringe. The end of the syringe should be capped off with the bung provided and kept in the back of the fridge between uses to a maximum temperature of 4°C. At the end of the day your colostrum should be frozen in a zip lock bag. Ensure that each bag is labelled with your name, hospital number and the expressing date. Syringes can be obtained from your midwife.
It can be stored in the freezer for:

  • 2 weeks in a freezer compartment of a fridge
  • 6 months in the deep freeze (-18°C)

For general storage information for breast milk see How Long Does Breast Milk Last?

Diabetes and antenatal expression

Some babies born to diabetic mothers can have low blood sugar levels due to high levels of insulin still circulating in their bodies 28. If baby’s blood sugar levels drop too low this is known as neonatal hypoglycaemia and can be dangerous for your baby. Breastfeeding as much as possible after birth is a good way to raise baby’s blood sugar levels and prevent hypoglycaemia. Because some diabetic mothers find their milk comes in later than usual 29 and others find their baby isn’t ready to breastfeed, harvesting colostrum antenatally can ensure a supplement is available as needed. There are benefits for the mother too. Breastfeeding can help protect a mother with gestational diabetes from developing diabetes in later life and reduce the insulin a diabetic mother needs.30

Blood glucose monitoring in the newborn

For guidance on blood glucose monitoring see:

  • The British Association of Perinatal Medicine’s Identification and Management of Neonatal Hypoglycaemia in the Full Term Infant, Framework for Practice, 2017. This document includes clinical signs and operational thresholds to guide interventions, and the recommended care for “at risk” infants born at term.
  • The Academy of Breastfeeding Medicine (US based) also has a 2014 clinical protocol for blood glucose monitoring.31


Expressing colostrum before birth is known as antenatal expression. It involves expressing and storing drops of colostrum during late pregnancy. Having some stored colostrum after birth is a particular advantage to any baby likely to be born needing mothers’ milk quickly, for example babies born to diabetic mothers because they might have low blood sugar. Because nipple and breast stimulation in pregnancy could potentially start labour, historically there has been mixed advice about the safety and advisability of antenatal expression for fear of premature birth. However, many National Health foundation trusts and breastfeeding charities have promoted this practice for low risk mothers for many years. A recent study looking at antenatal expression in diabetic women has helped provide more guidance on safety. Most organisations suggest antenatal expression be started after 36–37 weeks gestation. Harvesting colostrum is not recommended for high risk pregnancies, and there are a number of cautions to be aware of.

This article offers general information regarding antenatal expression of colostrum but it should not be construed as medical advice. Always discuss whether antenatal expression is appropriate for you with your own medical professionals who can advise you based on your medical history.