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Why Your Baby Hates Your Period

Photograph by Twenty20

It goes without saying that you're exhausted as a new mother. So when your body decides to let old faithful blow again, you're generally not jumping for joy. (Never mind that you're also too tired for jumping.)

As the cherry on top, many nursing mothers find that, when they have their period, their babies seem to be fussier right along with them. There's a reason for that.

First, some background.

The return of a breastfeeding woman's period is dependent on many factors. Some of them include genetics, if baby is sleeping through the night or if any supplemental formula or solids are being used. Every woman is different, but the average return is around 12 months.

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Andrea Jorgensen, IBCLC, from Lactation Care Inc. in Newton, Mass., works regularly with clients who report a dip in milk supply a few days before menstruation. This dips, which tends to last between 12 and 36 hours, not only worries Mom, but can make for one frustrated kid.

Not only can your little one be annoyed with the tap running low, but the taste of their milkshake can change, too.

Like progesterone, elevated levels of estrogen have a suppressing effect on milk supply and can make the alveoli—the milk producing cells in the breast—become more permeable. Because of this, the cell might leak and not be able to store as much milk. But according to Jorgensen, the data is conflicting on the effects of increased estrogen on women's milk supply.

"While it did have a depressing effect on the volume of milk, there wasn't any impact on baby's weight gain or growth," she told me. In other words, though the amount of milk may decline, it may be more concentrated.

Luckily, our bodies have a natural mechanism in place to help counterbalance that dip in supply. When babies demand more feedings, there's an elevation in prolactin levels, the hormone responsible for milk production. But if Mom is really concerned about her milk supply, adding a few pumping sessions to give the body the go-ahead to produce more could do the trick.

"There's no harm in doing so," Jorgensen says. "As long as all that extra time and effort isn't detracting from your ability to manage your day and interact with your baby."

So that's the supply side of things. There's another factor that could be throwing baby off her nursing game. Not only can your little one be annoyed with the tap running low, but the taste of their milkshake can change, too.

'There's a tendency in American culture to pathologize women's menstruation and women's reproduction in general.'

A study conducted in the '80s found an increase in sodium and protein, and a decrease in glucose lactose and potassium while a woman's progesterone levels were elevated. Similarly, if a mother has a breast infection and is taking antibiotics, the elevated sodium level in the milk can be less appealing to baby.

The flavor of human milk is a dynamic thing that changes every single day from meal to meal—so it's not as if the baby isn't down for change.

"Breast milk's flavor profile changes every day just as the course of what mom's eating," Jorgensen says.

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And while these hormonal changes can certainly affect the taste of breast milk, Jorgensen isn't totally sold on labeling baby a picky eater—or overselling the less-sweet milk as a negative. "There's a tendency in American culture to pathologize women's menstruation and women's reproduction in general. It might be interesting to consider the possibility that maybe it actually makes the flavor of the milk better. Who knows?"

Whether baby is annoyed with the smaller portions or hasn't discovered the deliciousness of a big bag of salty potato chips, fear not: the tantrums, like the periods, won't last forever.

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