Science confirms moms’ experience…again.

I’ve heard this from moms often enough to sometimes repeat it when I am counseling other moms: “Milk seems to come in faster and more abundantly with second babies.”

These images show the effect of pregnancy hormones after 6 and 12 days on breast tissue in mice that have never been pregnant (top row) and mice that have been pregnant once before (bottom row).  The mammary gland in previously pregnant mice responds earlier and produces more branching ductal structures, used in lactation.  New research shows breast tissue retains a cellular memory of prior pregnancy that makes response more rapid and vigorous in subsequent pregnancies.
These images show the effect of pregnancy hormones after 6 and 12 days on breast tissue in mice that have never been pregnant (top row) and mice that have been pregnant once before (bottom row). The mammary gland in previously pregnant mice responds earlier and produces more branching ductal structures, used in lactation. New research shows breast tissue retains a cellular memory of prior pregnancy that makes response more rapid and vigorous in subsequent pregnancies.

Now scientists have shown the mechanism by which this is more than just perception: epigenetic memory. In experiments  on mice, “the mammary glands start expanding faster and also sooner than for those experiencing pregnancy hormones for the first time,” says [researcher Camille] dos Santos.  “It’s as if the gland already knows those hormones.”

The description of the experiments stretches my brain to try to comprehend, but even I can see the difference in the branching in the illustrations published with the article in the May 7, 2015 issue of Cell Reports.

Of course, this is directly applicable for moms in the early days of breastfeeding. But I am also fascinated by these comments:

“These findings have led to another important line of research.  It is well known that women who become pregnant by age 25 have substantially lower rates of breast cancer than women who bear children later in life or not at all. …Dos Santos says her lab is now ‘trying to understand which of the modifications we found in this study might prevent development of breast cancer in a pregnancy-related manner.’ ”

Breastfeeding is important for moms and babies. Breastfeeding is also very important for moms their whole life long.

We want to know what you think!