Image by jcomp on Freepik

For over 75 days, neuroscientist Carina Heller embarked on an extraordinary journey, becoming what she jokingly refers to as the “most-scanned woman in science.” Each morning, she entered her university's brain scanner, lying still for an hour and a half to study how her brain changes throughout her menstrual cycle—both with and without oral contraceptives. Her pioneering research sheds light on a crucial yet often overlooked area in women’s health.

Understanding Hormonal Influence

Oral contraceptives, commonly known as birth control pills, contain synthetic versions of hormones like progesterone and estrogen. These hormones play a vital role in regulating reproductive functions, but their impact on brain health is less understood. While millions use these pills for various reasons—ranging from contraception to managing acne or menstrual symptoms—scientific insights into their effects on brain structure and function have lagged behind.

Heller’s findings, presented at the recent Society for Neuroscience conference, suggest that brain morphology and connectivity fluctuate daily throughout the menstrual cycle and can be influenced by birth control pills. This research is crucial, especially considering that many individuals begin taking the pill during puberty, a critical period for brain development.

A Gap in Research

Despite the widespread use of oral contraceptives—over 150 million individuals of reproductive age globally—research on their neurobiological effects remains sparse. Some individuals report reduced anxiety and depression, while others experience worsening symptoms. Understanding these varied responses is essential for empowering women to make informed decisions about their health.

Most existing studies focus on small sample sizes and single imaging sessions, which fail to capture the dynamic changes occurring in the brain. Heller's approach of “dense sampling,” where she repeatedly scanned herself, offers a more comprehensive view of these variations, revealing rhythmic patterns in brain volume and connectivity throughout her cycle.

The Adaptive Brain

During her study, Heller observed that while on oral contraceptives, certain brain regions showed slight reductions in volume and connectivity. Interestingly, these changes appeared to reverse after she discontinued the pills, demonstrating the brain's remarkable adaptability. This adaptability is a key insight into how hormonal fluctuations can influence brain health and function.

Laura Pritschet, a cognitive neuroscientist who collaborated with Heller, found similar results in her own research, where she scanned her brain over a 30-day menstrual cycle. Her findings indicated that higher estrogen levels enhance the connectivity of brain networks involved in memory and daydreaming, while progesterone appears to have an opposite effect.

The Next Steps

Looking ahead, Heller plans to compare her data with a participant diagnosed with endometriosis, a condition affecting a significant number of women. This comparison could reveal deeper insights into how hormonal changes may impact conditions linked to reproductive health.

As more researchers like Heller and Pritschet conduct similar studies, the hope is to fill the gaps in our understanding of how hormonal contraception affects women’s brains. This knowledge will ultimately enable women and healthcare providers to make better-informed choices regarding contraceptive methods and their broader health implications.

In summary, Carina Heller’s unique approach to studying her own brain serves as a groundbreaking step in women’s health research. By delving into the intricacies of how birth control affects the brain, we are one step closer to unraveling the complex relationship between hormones and brain function, paving the way for more personalized and effective healthcare solutions.


Nature 634, 1026-1027 (2024)

doi: https://doi.org/10.1038/d41586-024-03368-4