Book Review: This is Your Brain on Birth Control

Most of the books I review on the tremendoulas blog pertain specifically to the childbearing journey — getting pregnant, being pregnant, birthing, and postpartum. Today I will make a slight diversion into the territory of preventing pregnancy.


This is Your Brain on Birth Control: The Surprising Science of Women, Hormones, and the Law of Unintended Consequences, published in 2019 and written by Sarah E. Hill PhD, promised a neutral, up to date, scientific examination of our options, and I was excited to learn what she had to share (how couldn’t I with the intriguing subtitle!), even though most of the parents who hire me for doula work may feel the information in this book is irrelevant to them, either because by breastfeeding they have the side benefit of lactational amenorrhea, or because delaying a repeat pregnancy isn’t desired (especially if they struggled to get pregnant before or really crave closely born children).

However, for a mom who has just birthed by cesarean, it is commonly recommended to avoid giving birth again for around 18 months in order to reduce the odds of the scar rupturing. For all women who have just given birth, the risk of postnatal depletion increases when the babies are spaced closely together.

Regardless, all moms seem to be posed the question of their family planning or contraception goals around the 6 week postpartum mark. By this point in time, most midwives and doctors consider it safe for you to resume sexual intercourse. Having physically healed from birth, it is also considered safe to insert any intrauterine device (IUD) through the cervix.

Therefore, let’s consider the choices! We have today an overwhelming number of options. There are fertility awareness apps and fancy basal body thermometers like the TempDrop armband, Ava bracelet, and Femometer (which looks like a lipstick case) to help you monitor when abstinence or condoms are advisable. There are assorted barriers such as sponges, condoms, cervical caps, and diaphragms, which can (and in some cases should) be combined with spermicide for extra protection. We also have hormone injections, patches, devices such as vaginal rings and copper and hormonal IUDs, the morning after pill, and of course, “the pill” (of which we have close to a hundred types).


I’m copying below the table of contents so you can have a glimpse of what the book covers:

Part I — You Are Biology

  • 1. WHAT IS A WOMAN? Evolution’s answer to a philosophical question
  • 2. YOU ARE YOUR HORMONES. The basics, the controversial, and a fish with three genders
  • 3. YOU IN THE TIME OF FERTILITY. A twenty-eight-day case study on women’s sex hormones

Part II — This is Your Brain on Drugs

  • 4. HORMONES ON REPLAY. How the pill works, and what’s in yours
  • 5. SEXY IS IN THE EYE OF THE PILL-TAKER. Attraction and mate choice on the pill
  • 6. SEX ON DRUGS. Sexual side effects, hers and his
  • 7. THE CURIOUS CASE OF THE MISSING CORTISOL. The pill and your stress response
  • 8. WHAT THE FUNK? Your mood on drugs

Part III — The Big Picture

  • 9. THE LAW OF UNINTENDED CONSEQUENCES. The effects of the pill on other people’s bodies
  • 10. WHY DIDN’T I KNOW THIS ALREADY? Competition, politics, and self-deception
  • 11. WHAT NOW? A LETTER TO MY DAUGHTER. To pill or not to pill? That is the question

This book also includes an introduction plus a very lengthy back section loaded with notes from referenced scientific articles as well as an index.


Sarah Hill pretty much focuses on the pill in this book, though at times I wondered if some studies she referenced didn’t also include participants using hormonal IUDs or injections, too. With few exceptions, she divides all women into only 2 groups: “naturally cycling” (not on birth control) and “pill-takers.” I would have liked more information about non pill contraceptives than was provided.

Overall, I expected Sarah Hill to deliver the facts to me, and was pretty pleased to have that expectation met. I will focus on the facts in the below section, “key findings & takeaways.”

The biggest disappointment to me was her super feminist slant. Injecting her opinions into the book withdrew from some of the richness of the facts, I thought, and felt at times alienating to my Judeo-Christian worldview, which does not encourage loose sexual relationships (a purported benefit for pill-takers). However, I do genuinely appreciate that her point of view was probably very inclusive to other women, who no doubt have so much to gain from this book (probably more than a woman who has only ever had one partner).

I agreed with Sarah Hill on some things: the consequences of our existing pills are unacceptable, and we should keep conversation lines open with other women when it comes to our use and experience of the pill. This is for our individual safety and well being (so our sisters and friends can help us notice if we’ve changed for the worse after starting a new pill), for the general awareness needed by our public (so other women can be warned of dangers associated with the pill), and to corroborate for each other the symptoms that have in the past been dismissed as just “all in your head.”


To set an appropriate context for discussion of all the research on modern day mating psychology, Sarah Hill begins with a biological and evolutionary perspective on mating and the differences in brains between women and men. I actually enjoyed this section greatly. The main point here was that women have a much stronger instinct to be choosy about who we mate with than do men (who have more incentive to spread their seed widely). One of many examples why was that “children of single mothers, historically, are more likely to die from every recordable cause of mortality than are children whose dads stick around to help provide food, care, and protection” (location 283 on Kindle version), therefore, women historically would want to make sure they only mated with healthy, loyal, supportive men.

Sarah Hill proceeds to explain how the pill, by interfering with neurotransmitters in our bodies, influences every aspect of who we are. She details the activities of hormones in our body and explains in particular the hormones estrogen and progesterone which are involved with the ovulatory cycle (more commonly and perhaps inaptly called menstrual cycle).

These are the same hormones that we would want in birth control, however, chemists seem to have not quite figured yet how to synthesize progesterone in a form that matches what our bodies make, and it seems that different forms of synthetic progesterone have different issues for different people. Dr. Hill includes a nice chart showing which form of progesterone is found in which popular pills, so if you’re experimenting with different pills on yourself, you can use it as a guide to help you figure out which is the best form for you. One key point in the book is that there will be a range of effects (very positive to very tragic) for different pill-takers, but that shouldn’t come as a surprise to any reader who has conversed with friends about their different birth control experiences.

What was surprising for me to learn was that, even when they feel stressed out, women who are on the pill seem to have lost some ability produce cortisol, which is a sign of dysfunction in the hypothalamic-pituitary-adrenal (HPA) axis, and normally observed in people who have suffered complex trauma or excessive, chronic stress. As Dr. Hill reports, “Sometimes the researchers find that pill-taking women have a blunted cortisol response to stress (relative to naturally cycling women), sometimes the pill-takers have no cortisol response to stress, and sometimes—as was found in one recent study—levels of cortisol actually decreased in response to stress, which doesn’t make any sense at all” (location 2118). This effect can continue even when a pill-taker discontinues the pill, and may damage the immune system in addition to mood. Perhaps that is why we have the following sobering information:

pill use has now been linked to the development of multiple forms of autoimmunity, suggesting that the pill may have implications for women’s health. This is critical information to know, since 78 percent of people suffering from autoimmune diseases are women” (location 2304)

as well as this:

Almost half of all women who go on the pill stop using it within the first year because of intolerable side effects. And the intolerable side effect that is most frequently cited among those that caused them to quit is unpleasant changes in mood.” (location 2397)

I was particularly startled by the data on depression and suicide risk found in pill-takers. An awesome study of women in Denmark found those “on hormonal contraceptives were 50 percent more likely to be diagnosed with depression six months later, compared with women who were not prescribed hormonal contraceptives” (2418). Depression and suicide were especially pronounced for the teenage cohort of contraceptive users, and within that group, even higher for young women using non-oral products such as IUDs and patches (+220% and +180% increased risk of depression, respectively), even after testing for the influence of third variables! The most heartbreaking statistic in the book was that teenage users of hormonal birth control were three times more likely to have a successful suicide attempt than teens not prescribed birth control over the same period of time in Denmark. Now, I can’t speak to the challenges of being a teen mom or getting pregnant as a teen only to give your baby up for adoption, but either of those scenarios sounds so much better to me than suicide.

Other fascinating points in the book were more lighthearted, fortunately:

I learned that if you meet your future spouse while you are on birth control, you’re statistically more likely to stay married than a woman who meets her spouse while naturally cycling, and also more likely to be the unsatisfied partner if your marriage does not work out (where your naturally cycling counterparts may be more likely to be blindsided by their partners’ unsatisfaction). This information sits nicely next to research that shows a stronger libido in women who are naturally cycling, along with the author’s personal observation that she felt more alive when she came off the pill.

Another tidbit I enjoyed from this book was the fact that naturally cycling women have stronger memory than women on the pill. How sexually active college students trying to memorize the Krebs cycle for an upcoming exam reconcile that information with trying to not get pregnant before graduation is a dilemma many women may not have even realized they had.

Sarah Hill gave some really fun food for thought when she posed the possibility that birth control has increased refrigerator sales and impacted many other aspects of the economy (more obviously, womens’ participation in post-secondary education, grad school, and the workforce). Since birth control has resulted in more young adults delaying marriage, we now have a greater share of single households than in past generations, and that means less sharing of resources like home furnishings and appliances.

The most important piece of the whole book was the final chapter — a letter to the author’s daughter — which summarizes some of the warnings, cautions, and responsibilities that need to be taken with any birth control. I appreciate the candid remarks the author shares in this letter and value the freedom she grants her daughter to decide for herself what she will do with the information she is given. This is the mark of any good advocate: that she offers evidence based information for her client, patient, or family member, and then supports her no matter what choice she makes. God help me do the same!


This is not a book I would necessarily recommend to every woman I know. The research presented was definitely intriguing, and the key points important. Anyone with a passion for women’s health should take the time to go through it. However, I found the author’s messages to build more slowly than I would have liked, and felt that she could be boringly redundant. Worst of all (and some may lose respect for me on this, but I’ll say it anyway), her opinions were highlighted more boldly than I believe was necessary. If you have a fierce feminist agenda and crave up to date evidence with some confirmation bias mixed in, I would definitely highly recommend this book. Personally I (and I suspect many readers who have a traditional Judeo-Christian worldview), would have preferred a more neutral voice, so we could integrate the information into our own lives however feels best to each of us. At the end of the day, though, I was really grateful to have learned what I did from the book.

%d bloggers like this: