From sabotaging sex to axing attraction, new research is showing that the birth control pill can have impacts you never imagined. Dr Sarah Hill is a renowned evolutionary social psychologist who focuses on women and health. She is also the author of How the Pill Changes Everything: Your Brain on Birth Control.
The Psychological Impact of Hormonal Birth Control (HBC)
- Dr. Sarah Hill's interest in researching HBC stems from her personal experience of feeling a profound "waking up" approximately three months after discontinuing it, noting increased energy, libido, interest in men, and engagement in activities like downloading new music.
- Her mission is to empower women by providing scientific insights into how hormones, particularly HBC, influence their self-perception, relationships, and societal roles, emphasising that this conversation is relevant for everyone – women, their partners, and those who love women.
- HBC has been crucial for women's political and economic independence through recent history, enabling greater planning for education and careers by ensuring they can finish programmes without interruption due to pregnancy.
Natural Hormonal Cycles and Their Influence
- Women's natural ovulatory cycles involve predictable fluctuations of ovarian hormones, primarily estrogen (estradiol) and progesterone, which profoundly impact brain structure, function, mood, and behaviour. The brain is a plastic organism that changes its structure and function throughout the cycle.
- During the periovulatory phase (typically days 9-14/15 of a 28-day cycle), high estrogen levels lead to increased sexual desire, more frequent sexual behaviour, and a heightened preference for masculine cues (e.g., masculinised male faces, voices, testosterone scent) in potential partners, as the body prepares for conception. This phase is generally associated with feeling sexy and energetic.
- Conversely, during the luteal phase (after ovulation), progesterone dominance is associated with decreased sexual interest, increased sleepiness, hunger, and sometimes moodiness, as the body shifts its focus to potential embryo implantation.
- It is a misconception that women are more "hormonal" than men; everyone's behaviour and mood are influenced by hormones. Men's testosterone levels also fluctuate dynamically and unpredictably throughout the day and in response to various environmental and social cues (e.g., time of day, relationship status, presence of attractive women, competitive events, even the presence of weapons).
- The idea that sex differences are purely culturally imprinted is considered disempowering for women, suggesting they are passive products of patriarchy rather than having an evolved "female nature" shaped by inherited evolution and wisdom from successful ancestors.