Changing your birth control won’t change how much you love your partner, global study finds

Recent findings published in the journal Scientific Reports suggest that changing hormonal birth control habits during a romantic relationship might not negatively impact a woman’s feelings of love and satisfaction. The study looked at thousands of women across the globe and found that switching on or off hormonal contraceptives generally does not alter relationship quality. This provides evidence that for most people, choosing or changing a contraceptive method is unlikely to disrupt existing romantic bonds.

Hormonal contraception has been widely used by women around the world for over sixty years to prevent pregnancy. These medications work by temporarily stopping ovulation, which is the release of an egg from the ovaries. This biological process reduces the natural fluctuations of hormones like estrogen and progesterone that usually happen across a normal menstrual cycle.

Because of these hormonal shifts, women taking these medications often experience a biological state similar to the period just after ovulation. In addition to preventing pregnancy, this altered state is associated with lowered testosterone and changes in oxytocin levels. Oxytocin is a brain chemical famously linked to social bonding, trust, and romantic attachment.

A growing body of evidence connects these physical changes to a variety of psychological and behavioral differences. Some studies suggest that altering these hormone levels can affect a person’s mood, general well-being, and even sexual desire. Specifically, research has pointed to potential shifts in the types of traits women find attractive in a romantic partner.

One idea explaining these shifts is the ovulatory shift hypothesis. This concept proposes that a woman’s preference for certain characteristics in a partner changes depending on where she is in her menstrual cycle. During peak fertility, women might prefer men with highly masculine traits, but during non-fertile phases, they might favor more nurturing and dependable partners.

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Because hormonal contraception stabilizes a woman’s body in a non-fertile state, it might dampen the preference for traditionally masculine features. Building on this idea, the Congruency Hypothesis suggests that a woman’s romantic satisfaction depends on keeping her birth control status the same over time. Previous studies testing this idea have produced mixed results, with some supporting the hypothesis and others finding no such link.

“Millions of women worldwide use hormonal contraception. Yet we still know surprisingly little about how it might shape romantic relationships,” said corresponding authors Marta Kowal, a researcher at the Institute of Psychology at the University of Wrocław in Poland, and S. Craig Roberts, a researcher at the University of Wrocław and the University of Stirling in the United Kingdom. “One influential idea, the Congruency Hypothesis, proposes that what matters is not whether a woman uses hormonal contraception, but whether her use is consistent over time.”

If a woman met her partner while using the medication and later stopped, she might perceive him differently, the authors explained. The same logic would apply if she met him while not using birth control and later started taking it.

Much of the previous research on this topic focused on populations from societies that are Western, educated, industrialized, rich, and democratic, often referred to as WEIRD populations. Relying entirely on these specific populations can create a biased understanding of human psychology that ignores global diversity.

“Early studies supported this, but several more recent and well-powered studies did not,” Kowal and Roberts noted. “Moreover, almost all of this work has been conducted in WEIRD populations, so we decided to go beyond WEIRD. We used semi-representative samples from 51 countries to test the idea on a much broader scale.”

The authors specifically aimed to look at overall relationship satisfaction alongside the intensity of romantic love. To measure love, the researchers relied on the Triangular Theory of Love. This psychological framework divides love into three main parts: intimacy, passion, and commitment.

Intimacy involves feelings of emotional closeness, mutual understanding, and connectedness. Passion encompasses physical attraction, sexual desire, and romantic arousal. Commitment represents the active, cognitive decision to stay in the relationship and maintain the bond over time.

The researchers recruited an initial sample of 10,482 participants from 51 different countries and regions. For their primary analysis, they focused on a specific subgroup of 2,224 women. These women were aged 45 or younger, were currently in a romantic relationship, and provided information about their current and past birth control habits.

The average age of this specific group of women was about 32 years old, and their average relationship length was eight years. The participants completed a survey that asked about their relationship status, relationship length, and socioeconomic status. Socioeconomic status refers to a person’s social standing or class, which is often measured by their education, income, and occupation.

To test the hypothesis, the survey asked women if they were using hormonal contraception when they first met their partner. It also asked if they were using hormonal contraception at the time of the study. The scientists then categorized the women into groups based on whether their contraceptive use remained the same or changed over the course of their relationship.

Overall, 1,611 women maintained the exact same habits, meaning they either consistently used the medication or consistently avoided it since meeting their partner. Another 613 women had an inconsistent pattern, meaning they either started or stopped taking the medication after meeting their current partner. The participants also filled out a 15-item questionnaire rating their current levels of intimacy, passion, and commitment toward their partner.

The authors used statistical models to analyze the data, taking steps to account for factors like age, relationship length, and socioeconomic status. The data analysis did not provide robust support for the Congruency Hypothesis. The researchers found no significant differences in relationship satisfaction, intimacy, or commitment between the women who changed their birth control habits and those who did not.

“For most women, choosing or changing hormonal contraception is unlikely to meaningfully affect the amount of love or satisfaction they experience in their relationship,” Kowal and Roberts explained. “Among the 2,224 partnered women aged 45 or younger in our sample, we found no robust differences in intimacy, passion, commitment, or relationship satisfaction between women whose contraceptive use had changed since meeting their partner and those whose use had remained the same.”

“There was one exception, in one of our models, women who had changed their pattern of contraceptive use reported very slightly lower passion, on average, about 1.6 percent lower,” the researchers added. “Given the small size of this effect and the fact that it was not robust across models, I would be cautious about reading much into it.”

Similarly, they found no evidence that using hormonal birth control at the time of the study was linked to lower relationship quality overall. Women currently taking the medication reported similar levels of love and satisfaction as women who were not taking it. The researchers noted that this was slightly surprising, given past findings.

“There is a substantial literature connecting hormonal contraception to mood, to oxytocin functioning, and to reduced sexual desire, so many people would expect hormonal contraception to be meaningfully related to different experiences of love and relationship satisfaction,” Kowal and Roberts said. “However, if we consider how strong the experience of love is, our results become less surprising.”

The researchers also noticed major differences in birth control usage depending on the country. For example, current usage was as high as 71 percent in Honduras and as low as 3 percent in India. These wide gaps likely reflect differences in healthcare access, cultural attitudes, and national regulations rather than biological differences in reproductive preferences.

Interpreting these findings requires keeping a few limitations in mind. The study relied on a cross-sectional design, which means the researchers observed the participants at a single point in time. Because they did not track the same women over several years, it is impossible to know if changes in birth control directly caused any relationship outcomes.

“Our design was cross-sectional and between-person, comparing different women to each other,” the authors explained. “Women who choose to start, stop, or continue hormonal contraception may differ from one another in ways that also predict relationship quality, quite independently of the hormones.”

This design leaves the study vulnerable to selection bias. For instance, women with naturally higher sex drives might choose to use birth control more frequently, which could skew the results. Likewise, women who experience negative side effects might simply stop taking the pill, leaving only those who tolerate the medication well in the current user group.

Another limitation involves the study’s statistical power, which refers to a mathematical ability to detect very tiny effects. Recent analyses by other scientists suggest that if hormonal contraception does affect relationship quality, the effect size is incredibly small, often denoted in statistical models as an “r” value. The current study was not large enough to reliably detect those microscopic shifts, meaning the findings cannot entirely rule out minor changes.

“First, our null results should not be interpreted as definitive proof that hormonal contraception has no effect on relationships,” Kowal and Roberts said. “Absence of evidence is not evidence of absence. We were well powered to detect the effect size reported in the original Congruency Hypothesis study, but we were not powered to detect the very small effect (r = .04) found in the most recent meta-analysis on the subject.”

The slight drop in passion observed in one specific statistical model also requires context. The authors believe this minor shift is tied to the length of the relationships rather than the medication itself. Women in longer relationships were naturally more likely to have changed their birth control habits at some point over the years.

“Second, the small passion finding should be treated very cautiously,” the authors noted. “It appeared in only one of our two models, it was borderline, and we think it most likely reflects confounding rather than any pharmacological effect. Women in longer relationships were more likely to have changed their contraceptive use, and passion tends to decline with relationship length anyway.”

Memory recall is another potential issue, as women were asked to remember their birth control habits from when they first met their partners. Even though very few women selected the option indicating they could not remember, it is always possible that some participants recalled their past habits incorrectly. Future research could benefit from longitudinal studies, which follow the same people over months or years, to provide a more accurate picture of these transitions.

“Misinformation about hormonal contraception and its psychological side effects is widespread, and many women encounter contradictory information online, especially when making decisions about their own bodies,” Kowal and Roberts concluded. “Our findings offer some careful reassurance, at the population level, we found no meaningful link with love or relationship satisfaction.”

“This study was part of a larger research project, conducted together with Piotr Sorokowski, Michał Misiak, W. P. Malecki, and Agnieszka Sorokowska, and was funded by the IDN Being Human Lab, University of Wrocław.”

The study, “Hormonal contraceptive use is associated with love intensity across 51 countries,” was authored by Marta Kowal, Piotr Sorokowski, Michal Misiak, W. P. Malecki, Agnieszka Sorokowska & S. Craig Roberts.