Everything You Need to Know About Expressing and Pumping During Pregnancy

Some Background About the Way that Breasts Make Milk During Pregnancy

Your breasts start to produce milk (colostrum) from around 16-20 weeks of pregnancy. This is totally normal.

Some women will notice this instantly as their nipples start leaking milk. For other women, this will come as a surprise as they have never seen a drop come out.

Do not panic! We are all different and all a variation of “normal.”

But from around the middle to end of the second trimester your breasts can actually make milk; whether you see it or not!

The breasts only make tiny quantities of milk at this stage, as the hormones of pregnancy stop the milk cells from being able to make large volumes of milk until both your baby and the placenta are born.

Why is Everyone Talking About Expressing Milk During Pregnancy?

Research showed an increased risk in a baby developing diabetes later on in life if they were fed formula milk and their mother had diabetes in pregnancy. Babies born from mothers who have diabetes during pregnancy are more likely to have low blood sugar levels soon after the birth. This is known as hypoglycaemia.

Hypoglycaemia can potentially affect whether the baby is able to feed at first. If you’ve ever had low blood sugar you will know that it makes you feel really low on energy, tired, and shaky, among other things. Now, imagine a newborn baby trying to breastfeed when they feel like this, not easy!

And, because a baby may not be able to breastfeed to naturally increase his blood sugar level, the midwives or nurses would often have given the baby formula milk instead.

In order to stop giving so many babies formula milk for low blood sugar levels, midwives have started to advise some mothers to hand express their milk during pregnancy, around 35-36 weeks of pregnancy.

Mothers were instructed to expressed anywhere from twice to six times per day and to collect the milk in tiny syringes and store the milk in the freezer. They would then take this antenatally expressed frozen milk into the hospital when they went into labour. This extra colostrum could then be used instead of formula milk if the baby had low blood sugar levels.

A Few Safety Questions with Antenatal Hand Expression

Since then, this practice has gotten more and more common, with many women being advised to express their milk in pregnancy for lots of different reasons.

Until recently, we have not had any good scientific research which has shown whether this practice is advised and safe. There was a small concern that expressing during pregnancy could lead to preterm labour.

When our babies breastfeed or we express we produce a hormone called oxytocin, which helps muscles contract around the milk cells and push the milk down the ducts to the nipple and baby/pump. This is the same hormone which also makes our uterus contract during labour.

Scientific Research Investigating Antenatal Expression

In 2017, the first and only randomised control trial was published, which investigated whether antenatal expression for women with diabetes in pregnancy is safe.

The researchers stated that the “research showed that not only is expressing breast milk before birth safe, but it increased the proportion of mothers who exclusively breast milk fed their child within the first 24 hours of birth and up to seven days after birth.”

Please note: this research only looked at women with healthy pregnancies, who were hand expressing from 36 weeks of pregnancy (not earlier) and only for two times each day (not more).

Using a Pump During Pregnancy

The research and technique of antenatal expression has only ever been done with women using their hands to express, not with a pump (whether a hand-pump or an electric pump). Therefore, it is not advised to use a pump to antenatally express milk.

If you are pregnant and still breastfeeding or expressing for another child, pumping should not cause preterm labour in a healthy pregnancy. Many mums continue to provide breastmilk for their child while pregnant with their next one.

If you have any concerns it is always best to discuss this with your health care provider.

In Summary

Always discuss antenatal hand expression with your midwife or obstetrician first to check if it is a good option for you and your pregnancy.

Never use a pump during pregnancy.

If you have diabetes, discuss this further with your midwife or obstetrician to create a plan for you and your baby.

If you have been advised to antenatally express your milk, your health care provider will show you how to hand express and provide you with an instruction and collection kit.

Do you have any breastfeeding questions? How would you describe your own breastfeeding journey? Let’s have a chat here or on our Medela Australia Facebook page.