E104: The Intellectual Domain of Family Planning

Katie: Have you ever heard that being on birth control might make you attracted to the wrong partner? Could your hormones on the pill lead you into a relationship you'd regret? This has been all over social media lately, and it's based on research that has been thoroughly debunked. So today, I'm going to tell you the story about how I know that.

I'm Katie Ward. I'm a women's health nurse practitioner. I'm a professor in the College of Nursing, and I recently finished a PhD in biological anthropology, which is going to be relevant to today's story.

I'm here, as always, with my co-host, Dr. Kirtly Parker Jones. Kirtly is a reproductive endocrinologist who also studies hormones, and she's encouraged my studies every step of the way. But today, I'm going to hog the conversation because this is a story I am really anxious to tell.

Kirtly: Okay, Katie, the microphone is yours.

Katie: Thank you. Thank you for going on this journey with me.

Kirtly: Yeah, right.

Katie: So this episode today is exploring the intellectual domain of family planning. I've been on a career-long intellectual journey through some fascinating and some challenging science here, so I'm going to take you back to where this started for me.

Sixteen, 17 years ago, I was pursuing my doctorate in nursing practice, and that curriculum allowed me to take an elective. And I'd always been interested in anthropology, so I enrolled in an evolutionary psychology class with a very respected researcher in that field.

Evolutionary psychology is kind of the study of how human behaviors might be adaptive, that is ways of being that helped our ancestors survive and that persist with us today. And so you kind of look backwards and say, "How might that have been useful?"

And if you're interested, I'd highly recommend "The Hidden Brain" podcast. It explores a lot of these ideas really beautifully.

But what I was interested in, what kind of captured my imagination, was research suggesting that, during the fertile phase of the menstrual cycle, that is the three to five days in the middle of the cycle where intercourse can lead to conception, that the human female might behave differently than the rest of the month.

People theorized that perhaps you'd feel things differently and, more importantly, be attracted to different people. The idea was that even though pregnancy might not be your intention in your intellectual brain, your egg was motivating your body to do things to ensure fertilization. And not just any fertilization, but rather with someone who had the best genes, and even if those genes weren't the genes of the partner you chose in life.

So I was intrigued by this possibility. We certainly see fertility-driven behavior in other animals. Animals we're familiar with, cats, dogs, cows, are physiologically capable of sex only when they're fertile. Their anatomy literally changes to make it possible. Birds are very picky about their mates, and in lots of animals, the males kind of battle it out with each other, and only the winner of those competitions gets the girl, so to speak.

So it sort of makes sense to apply some of this evolutionary logic to human behavior and to test these hypotheses. People wondered if we would see subtle shifts in who females were attracted to when they're fertile. It's a hypothesis, and it's certainly worth testing.

I dove into this research with abandon, because as someone prescribing family planning, if there was a thing that shifted around ovulation and we were turning that off with the birth control pill, certainly women deserve to know.

Kirtly: Wait a minute. During the fertile window, we were only looking for the big, strong, bad, dark, handsome creeps, and what we really ought to have is the fathers who are going to stick by us.

Katie: Right? That's the crux of this hypothesis.

Kirtly: Okay. Sorry. Keep going.

Katie: And then people would sort of come up with this whole dual strategy idea, that you want both kinds of guys, the strong one to mate with, but the nice one to help you raise your children.

There were studies out there on everything. They would try to figure out when people were fertile and then check to see if they were different. And probably the most famous of these studies was "Do strippers get more tips when they're ovulating?"

Kirtly: Oh, god.

Katie: Do waitresses get more tips? Do women wear more red during that fertile window?

And then lots and lots of studies on who you're attracted to. Do you like beards or no beards, or deep voices, or symmetrical faces? Or do you take more financial risks?

There were little studies everywhere, usually not big studies, and most of them had a lot of flaws in how they calculated the fertile phase. But the ones that got published seemed to point to this phenomenon, and it got its own name, the ovulatory shift hypothesis, or sometimes the good genes ovulatory shift hypothesis. And this research has been going on for a generation.

So in 2014, a couple of researchers took on what we call a meta-analysis, where they take all of these little studies and pile them into one big study and sort of see where all that data points if it had been done all at once.

And so these two groups looked for all the research they could find. And they even wrote authors who published stuff and said, "Hey, do you have anything in your desk that you didn't publish because it didn't turn out the way you expected?" So they really tried to get their hands on everything.

Both groups really looked at pretty much the same literature. There was a little difference between the two groups, but by and large, the same studies were included in these two meta-analyses.

They did ask slightly different questions and use slightly different statistical analyses, but what was interesting is these two groups came to completely opposite conclusions.

One group said, "Robust preference shifts. Can't miss it. It's everywhere." And the other group said, "Not only is there nothing there, but there's really clear evidence that the researchers are cooking the books." That is, they're adjusting their methods or statistics to show differences that didn't actually exist. And for the nerds out there, this is a thing called "p-hacking."

So 2014 was significant for me because it was also the year I decided to go back to school after finishing the nursing doctorate and do this PhD in anthropology. This is where I stepped in, this hot debate between these two camps of people whether or not the ovulatory shift hypothesis was a real thing.

What I came into school thinking is, "I know how to do this. I know something these psychologists don't know, and that is that women with IUDs are still ovulating, at least most of them, and they don't necessarily know where they are or when they're ovulating because they're not having regular periods to cue them into that information." So I thought, "I am going to walk into this debate and settle it once and for all with my amazing study design." That was my plan.

Fortunately, the advisor from that original evolutionary psychology course was willing to take me on, and Kirtly was willing to be on my committee. And I settled in to work on this PhD.

So I spent a few years paying my dues as an anthropology student learning about all the aspects of anthropology, and I spent a year doing some lab work on chimpanzees. In the meantime, I was reading everything that came out on this ovulatory shift hypothesis thing.

And it turns out I wasn't the only one who thought we could do better studies. So those two competing meta-analyses really highlighted a bunch of flaws in that research. In the meantime, the field really improved dramatically. Researchers started using larger sample sizes, they analyzed the data correctly, they looked at within-person changes instead of comparing two different groups of people. They got better at identifying the fertile phase and applying more robust statistical testing.

And here's what they found time after time: nothing, zip, nada, zero. No preference changes across the menstrual cycle. So really, once people started doing better research, there was just nothing there.

There was a brief, sort of subtle uptick in interest in sex generally, but not in who you're attracted to. And to be honest, this was a little tough for me as a researcher because I had to think up a whole new thing to study.

Spoiler: I found something else to study because feelings and hormones do change across the cycle, but it's not this ovulatory shift towards good genes or bad genes idea.

So that is the story I want to tell, that I've spent the last nearly 20 years really immersed in this research. I've read everything that's been written. And I am absolutely, positively convinced that there's no evidence that who you're attracted to changes in this specific way across the menstrual cycle.

That was a long story. Thank you for going with me.

Why are we talking about this now? As someone who's thinking deeply about family planning and paying attention to what my patients are coming in telling me, and I'm listening to what's on social media and reading what's in the news, there are a lot of platforms where influencers are telling people compelling stories about how their birth control, especially hormonal birth control, the pill, IUDs, implants, have harmed them. That's sort of how these influencers are telling their story, and they're encouraging people to switch to cycle tracking apps or wearable technology.

And I want to be clear, these can be really valuable approaches to following your menstrual cycle, especially if you're trying to get pregnant or if you're not at risk for pregnancy and you simply want to understand your body better.

I love the cycle tracking apps. I'd encourage anybody to tune into those signals. There are some really interesting things you can see that your body is doing. Your cervical mucus changes. After ovulation, your body temperature goes up a small amount. All of this can be really fascinating and fun to learn about how your body works. Genuinely educational.

But if you're using these methods for contraception, there are some limitations. First, they require constant vigilance. If you take your eye off the ball, if you're not consistently paying attention to the data, say you go on vacation or it's the holidays, it's easy to slip up.

And the irony, one of the things that does increase during your fertile window is an interest in sex. So that little nudge can be hard to talk yourself out of if that's the one nudge you get. 

Second, ovulation is best identified retrospectively after it's over, when your temperature rises. So if you ovulate a day or two earlier than expected and you've had sex based on your predictions, well, sperm can live in the reproductive tract for up to five days. An eager egg that ripens quickly plus long-lived sperm can equal an unplanned conception. So that makes the window where you need to avoid unprotected sex fairly wide and somewhat unpredictable.

And then third, and I think sort of most important today, is you're outsourcing this decision to technology. So if your app's algorithm hasn't quite learned you yet, or the data is corrupted, or you take your ring off for a couple days, or their servers go down, and you're not really paying attention but relying on your phone to tell you what's safe, you could end up where you don't want to be.

And so in the real world, the apps are actually a fair amount of work to use.

What concerns me is that, within this sphere of influencers encouraging people off hormonal contraception, I hear references to this old research that's really been proven not true, that if you are on the pill or hormonal birth control, you might get in a relationship with the wrong person, that your mate preferences are somehow changed or distorted by using hormones.

I want to say this again and over and over: That research has been resoundingly falsified. There's no evidence that people get in relationships because they're ovulating or because they're using hormonal birth control.

What's concerning me now is there's the social media influence out there, people are being influenced onto the app, and then researchers are kind of using that study population to do new studies.

The problem becomes apparent right away. You've got a study population that was primed before they became research participants based on what they heard on social media, and they're getting recycled back into that influencer ecosystem. And then this recent evidence starts to look like there's something there in terms of how people feel about their partners. So that's a problem with the researcher pipeline.

But I want to throw this out there. If you really want to study how hormones affect desire or mate attraction, I've got the population for you: people using IUDs who are naturally cycling behind the scenes and weren't curated through an app, already influenced into this controversy.

So, yeah, that's the story I wanted to tell. I know that's taken up a long time and I've kind of hogged the whole episode here.

I don't want to dismiss real side effects on birth control. There are side effects. People experience mood changes and weight gain and unexpected bleeding, and those are all legitimate concerns. And your healthcare provider can help you manage those. But the message that you might end up with the wrong partner is misinformation. There's no scientific evidence for it.

Attraction to your partner ebbs and flows with time, and that's okay. But your contraceptive choices should be based on what works for you and your body and the importance of not getting pregnant right now.

I want people making those decisions with their healthcare provider, not based on some influencer they heard on TikTok or Instagram who doesn't know this research the way I do.

So thank you for letting me share my long journey.

Kirtly: Well, I'm a little worried about my privacy if I think about all these apps and who knows exactly where I am in the cycle, because all of a sudden, I'm going to be having more advertisements for pads or tampons or whatever, or chocolate, if they think that chocolate cycles with me. You could go back to the 7 Domains of Chocolate and check out that one.

Well, I'm going to grab the mic back and . . .

Katie: It's yours.

Kirtly: And before we sign off on this episode, I want to get back to our, or your, meaning our listeners, mental or physical spreadsheets about your family planning plans.

As you plan out the effectiveness, risks, and benefits of all the contraceptive methods available . . . And maybe you don't do it that way. Certainly I did, and Katie probably did in her way. But what you would do if your method fails, or you or your method fails. Abortion? Have a baby? Adoption?

It is really important to know yourself. And the biggest reason that birth control methods fail is the human factor. If you know yourself and you always know how much money is in the bank and you check it every day, and you always brush your teeth and floss them, and you always put on your seatbelt before the car starts and yells at you, and you have a partner who always supports your method, you might be a candidate for methods that take a lot of daily input.

These compulsive traits of checking your money and always brushing your teeth and doing things always, always, always are hard to maintain if you have a chaotic lifestyle. And isn't that all of us sometimes? So if you do shift work or you have small children at home or . . . You get the drift.

Anyway, choosing barrier methods like condoms, which require your partners be equally OCD, or a diaphragm takes planning. And you and your sex partner are not thinking about planning when they have to think about putting the diaphragm in or using a barrier method. So you're asked to be doing your most cognitive work when you're least likely to be doing that.

And especially those methods that require that you test your temperature and your mucus and your hormones and track daily, you have to have no slip-ups, no irregular periods, no breastfeeding, no vaginal infections, no forgetting, no having sex on days that are risky.

If you think your app is going to figure all that out for you and keep your partner away, good luck with that.

The theoretical failure rate of these methods is 2% per year, meaning 2 out of 100 people who use these methods perfectly every single day will get pregnant per year. Now, you stack the years together and they start to add up.

But the real-life failure rates are 25% per year, meaning one out of four women using these methods in real life are going to get pregnant per year. And you add those years together and they stack up. So you have to have a backup plan.

Now, over my lifetime, I've used almost all the methods because they were right for me at one time or another. I made a calculated choice for all of them. There were many years that I didn't think sex was worth the risk. My teen years. So abstinence was the right choice. I didn't party or drink or go out at night. No behaviors that might put my abstinence at risk. Yeah, I know I was boring, but I was never bored.

There were years that I had irregular periods, and I used birth control pills to control my cycles.

There were times when I was working 100 hours a week with multiple nights on call. I couldn't even figure out what day it was. And during those years, I used an IUD where I didn't have to think about anything.

There were years when my life was more settled at 60 hours a week and I had regular cycles. I used a combination of a diaphragm, which is a barrier method, using it all the time, combined with abstinence during my fertile period. And as a reproductive endocrinologist, I knew the times very well, and I had the perfect partner.

And there were times when I got grouchy before my periods, PMS-y, and I needed to be 100% in charge of my emotional state for my clinic and my home, and I went back on hormonal methods taken continuously.

They all had risks and benefits, and that's what I was looking for at each time of my life. And you as listeners who are reproductively capable will, too.

I had a partner who was 100% beside me. We had one pregnancy and one child, literally planned to the minute. If this sounds very obsessive-compulsive . . . It does, Katie, doesn't it, now as I think about it? Well, it certainly was. I took my fertility very seriously, and I was lucky.

Katie and I have advanced degrees in family planning, and I have an advanced degree in infertility. We take the science and the behavioral science of family planning and baby making very seriously. We want you and the people you love to have the life that you plan, remembering that women plan and God laughs. But to the best of your ability, we want you to have the life you plan. We want you safe, we want you happy, we want you smart about your choices, and we really want to keep those choices available.

We spent our whole careers and whatever intellectual firepower Katie and I have got together, we have put on this hope and this plan.

So family planning is an intellectual, not an emotional, decision. But our emotional splatter, as we talked about in the emotional domain, it splatters our spreadsheets. So you really have to know yourself and make the best plan for you at the time and not let influencers influence you with methods that may not be the best for you.

Katie: Thank you, Kirtly, for helping me think about this, really, for my whole life. I'm a lot more reckless than you are.

Kirtly: I'm very risk-averse.

Katie: Like you, I think I have tried all the methods that were available to me over the years. And you're right, different methods for different stages of life. But it does drive me a little crazy to hear people being told things that I know are just so not true.

And so I think that's why I really wanted to get on the soapbox for this domain, because that one in particular, I know I'm the expert on this. You are not going to pick the wrong mate. I mean, you might pick the wrong mate, but it's not going to be because you were on birth control.

Kirtly: No.

Katie: So thank you, everyone, for listening to us on this domain, and I hope you'll join us for all the domains of family planning. You can get them on every podcast app out there, or at womens7.com on the internet.