There are many women who will tell you their early breastfeeding experience was easier with the second baby. In particular they will say that they had better milk production. Some of this ease of breastfeeding the second time around is undoubtedly due to mother being more relaxed, already having experience recognizing baby feeding cues and knowing how to get baby to latch on well. New research indicates that these anecdotal stories may also have a scientific basis to back them up.
Camila dos Santos of Cold Spring Harbor Laboratory in New York and her colleagues looked at the mammary tissues of mice prior to pregnancy, during and after first pregnancies, and again during and after subsequent pregnancies. In their research they confirmed that pregnancy is the key change agent for the mammary gland.
During the first pregnancy, as any pregnant woman can tell you, there is a tremendous expansion of cells within the breast tissue. The pregnant and lactating breast has alveoli (hollow cavities, a few millimeters large) lined with milk-secreting cells and surrounded by epithelial (surface) cells. The alveoli join to form groups known as lobules. Each lobule has a duct that drains into openings in the nipple. The results of the dos Santos study showed that many of these cellular changes to the alveoli and epithelial cells created during the first pregnancy are maintained after the first period of lactation has ended.
When the test mice became pregnant for the second time the mammary tissues responded to the pregnancy hormones more quickly than during the first pregnancy. The mice were also seen to create additional alveolar structures and additional epithelial cells during the second pregnancy. This increase in cellular structure enhances the body’s ability to produce mature milk and produce it more quickly. The researchers suggest that the cellular “memory” from the first pregnancy primes the body for mammary function in the future.
Looking at this “lactation cellular memory” from a human evolutionary perspective it has a clear advantage. The mother with her first baby has more time available to spend feeding the baby. When baby #2 (or more) comes along the mother needs to be able to feed the baby and keep up with the needs of older children. Those mothers who had the ability to produce a greater milk supply for subsequent babies had the greatest likelihood of their genes being passed on to the next generation.
This study gives hope to mothers who struggled with milk supply with their first babies and provides another layer to the explanation why there was more breastmilk the second time around for mothers who have already had a second baby.
Even though your breasts will be primed for increased milk supply with baby #2 there is always value in getting encouragement and information from a knowledgeable breastfeeding supporter if you are currently struggling with breastfeeding or if you are expecting a second baby and struggled the first time around. To contact a La Leche League Leader or find a meeting near you click HERE.