Hi everyone, welcome to the LactFact weekly podcast, which highlights recent, clinically relevant research, policy statements, and protocols that you, as a practicing lactation professional, should know about. I am your host, Dr Anne Eglash. I am a board-certified family physician and breastfeeding and lactation medicine specialist at the University of Wisconsin School of Medicine and Public Health.

This podcast is written and produced by the nonprofit organization IABLE, which is the Institute for the Advancement of Breastfeeding and Lactation Education. There are no commercial funders for this podcast series.

Today’s LactFact comes from:

Article– Does Antenatal Expressing Affect Onset of Lactogenesis for Women With Diabetes? Results From a Randomised Controlled Trial and Cohort Study
First author-Anita Moorhead at the 1 Judith Lumley Centre, School of Nursing and Midwifery, La Trobe University, Melbourne, Victoria, Australia
Published– Australian and New Zealand J of Obstetrics and Gynaecology Accepted for publication Dec 15th, 2024

For background:
Antenatal colostrum expression has become a popular practice in the USA, Canada, Australia, NZ, UK, and probably other places. The practice is not new- it involves expressing colostrum during pregnancy, which may be leaking anyway, in case the infant needs supplementation in the first few days of life. For example, newborns might need supplementation for low blood sugars related to gestational diabetes or being small for gestational age. We know that there are a lot of infant risk factors that trigger newborn blood sugar screening which unfortunately tends to increase the likelihood of early supplementation.
Some educational resources have claimed that expressing colostrum during pregnancy is associated with faster secretory activation. In this LactFact I am using the term secretory activation for the ‘milk coming in’ or the older term, lactogenesis II.

The researchers in today’s study evaluated whether it is true that expressing colostrum during pregnancy is really going to bring on secretory activation earlier.

They compared 3 groups of women.
They started with participants from the DAME study. This was a RCT of women who had diabetes during pregnancy, where 319 women expressed colostrum during pregnancy and the other group of 315 women did not. That study looked at whether providing the colostrum early pp decreased newborn admission to the NICU for low blood sugars, which it didn’t. but the study showed that expressing colostrum starting at 36 weeks of pregnancy is safe.

In addition to those 2 groups of women with diabetes during pregnancy, this study recruited 210 women who didn’t have diabetes who were not advised to express colostrum antenatally. This allowed them to compare timing of secretory activation between women with diabetes with and without diabetes, and it was only ½ the women with diabetes who did colostrum expression during pregnancy.

They measured onset of secretory activation by asking the participants when they noticed that their breasts were feeling fuller. They tried to get this nailed to the hour, as close as possible.

They defined a Delay in the Onset of secretory activation as noticeable fullness that didn’t happen until after 72 hours pp.

In their results:
They found that 58% of the women with diabetes who did antenatal colostrum expression had a delay in secretory activation, compared with 56% of those had diabetes who did NOT do antenatal colostrum expression. So basically there was no difference in the timing of secretory activation whether they expressed colostrum during pregnancy or not.

Many fewer women without diabetes, all of whom didn’t do antenatal colostrum expression, had delay in secretory activation. The reason for this is likely because the women without diabetes were much less likely to have a BMI over 30, as compared to the women with diabetes. This makes sense because several studies have shown that elevated BMI is associated with a delay in secretory activation.

So, bottom line, this study shows that secretory activation occurs later in women with diabetes, higher BMI, and antenatal colostrum expression had no impact on secretory activation.

My personal comments are that I am not surprised that expressing colostrum during pregnancy does not hasten secretory activation. Basic physiology is that the drop in progesterone postpartum, along with keeping the prolactin up through frequent suckling, is key to orchestrating the process of secretory activation. This involves the fences between the milk producing cells, called tight junctions, to close in order to start collecting milk in the alveoli.
Antenatal expression can be exciting for some because they can collect a fair amount of colostrum and become quite skilled at hand expression. But others see this as another chore, and many women cannot express much colostrum. There is evidence that some women become discouraged about breastfeeding when this happens.

So far, we have not proven advantages to antenatal expression other than evidence that the practice leads to greater comfort with hand expression. It behooves us as healthcare providers to have an evidence-based discussion with our patients about what the real advantages are, so that they can make their informed decisions on whether to do this. And the bottom line is that antenatal colostrum expression will not bring the milk in faster.
I want to extend a huge thank you to the authors for publishing this very important study. Touche and well done!

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I will talk to you again in 2 weeks!