1031: Sarah Hill | How Birth Control Rewires Women's Brains Part One

Mood Effects

Hormonal birth control significantly impacts mood and stress responses. Sarah Hill explains that synthetic progestins in birth control pills lack the calming effects of natural progesterone, leading to increased anxiety and depression risks 1. This is because the synthetic hormones do not produce allopregnanolone, a neurosteroid that helps relax the brain. Additionally, women on the pill experience a blunted cortisol response, similar to those with chronic stress or trauma, making stress management more challenging 2.

Women who are using hormonal birth control because they're not getting actual progesterone, they're getting this synthetic progestin that doesn't get metabolized the same way.

--- Sarah Hill

This altered stress response can contribute to the development of anxiety disorders, particularly in teenagers 3.

   

Attraction Shift

Hormonal changes from birth control can alter attraction preferences and partner satisfaction. Sarah Hill notes that women who choose partners while on the pill may experience shifts in attraction when they discontinue it, sometimes leading to increased or decreased attraction to their partners 4. This is due to hormonal influences on libido and attraction cues, which can change when natural hormonal cycles resume.

It's possible that for some women, because they're not really prioritizing those kinds of cues when they're choosing their partners, that all of a sudden when they're off the pill and they start to care about those things again, that they realize that their partner isn't really hitting all the right buttons.

--- Sarah Hill

The balance between seeking genetic quality and long-term partner investment is also affected, as hormonal birth control can suppress cues related to genetic fitness 5.

   

Societal Impact

The societal implications of hormonal birth control extend beyond individual relationships. Sarah Hill discusses how birth control influences reproductive investment and social behaviors, highlighting the evolutionary differences in parental investment between men and women 6. Women historically have had to be more selective in choosing partners due to the higher reproductive costs they bear.

Females are actually defined as females in part because they make a larger investment.

--- Sarah Hill

With birth control reducing the consequences of sex, it raises questions about whether women will adopt behaviors traditionally associated with men, or if evolutionary instincts will prevail 7.