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The neurobiologist Belinda Pletzer from the University of Salzburg is researching the psychological effect of the contraceptive pill. She is focusing on the neurobiological effects on the structures inside the brain – and whether these are reversible. She is particularly interested in puberty as one of the most sensitive phases of brain development.

There are about 9000 known studies on health risks and side effects of the pill. In addition to physical symptoms such as weight gain, high blood pressure and thrombosis, the psychological effects have also been studied. Until now, however, only about fifteen studies have explored the influence that the contraceptive pill has on the brain. As she has studied amongst other things biology and psychology, observing the causes of psychological effects on the brain is also an appropriate method for Pletzer.

In her study, the researcher is looking at contraceptives which contain two different active ingredients:

  • Levonorgestrel has androgenic – as in more masculine – effects;
  • Drospirenone has an anti-androgenic – as in more feminine – effect;

Women react very differently emotionally when taking the various birth control pills available. Pletzer adds:

“For some women, using these may cause depressive moods. For others, they have a stabilizing effect. After all, some birth control pills are prescribed for premenstrual syndrome (PMS) as well.”

PMS refers to complex physical and emotional discomfort associated with a woman’s menstrual cycle.

Cognitive tests

The project aims to reveal what distinguishes women who can tolerate the contraceptive pill easily, from women who cannot. It also aims to study how the various contraceptives affect the brain during sensitive periods of the brain’s development, such as puberty.

The tests are carried out using fMRI scans at the Christian Doppler Clinic. The test subjects have to solve various cognitive problems and their scans must be recorded in order to determine whether taking the pill alters the brain structure or brain activity.

The tests are performed before, during and after taking contraceptives. After a contraceptive pill has been discontinued, a check is carried out to see whether the effect is reversible.

Pletzer works at the Centre for Cognitive Neuroscience in Salzburg. Her project was awarded a €1.5 million ERC Starting Grant from the European Research Council. The exceptional 36-year-old researcher studied biology, psychology, philosophy and mathematics and has two doctorates. She is also the mother of four children. The funding runs for five years and will allow her to conduct a comprehensive study with 300 test subjects.

An interview with Belinda Pletzer:

DDR. Belinda Pletzer , NAWI Salzburg
BRD. Belinda Pletzer, University of Salzburg (c) Andreas Kolarik/Herbert Rohrer


Are there any reasons why there are hardly any studies to date on the pill’s effect on the psyche?

When we talk about the psyche, we think about emotional well-being. We have known since the 1960s that the pill has an effect on the psyche. There are also studies on this, but the results are contradictory. Some studies have found an increase in depression, whereas others have shown stabilizing effects on emotional well-being. Both have merit, women have different reactions. These effects have been observed by gynecologists and proven in studies.

I am concerned with the neurobiological structures in the brain – and as of yet there are practically no relevant studies on this. For example, there are studies that examined in group comparisons whether the brain structure of women who take the pill differs from that of those who do not. This is questionable from a methodological point of view. Every person is different.

We are conducting a longitudinal study and comparing the development of women’s brain structure before, during and after use of the pill.

What kind of cognitive tasks do the test subjects have to perform during the tests?

Because there are scarcely any studies in this field, we are trying to cover cognition in as comprehensibly as possible. As a general rule, these are the aspects – spatial, verbal and memory. We test:

  • Navigational ability
  • Working memory
  • Verbal fluency
  • Face recognition ability

For facial recognition, we did a preliminary study wherein we were able to show that facial recognition skills are improved when taking certain types of contraceptive pills. Face recognition has a correlation with the gray mass in the area of the brain responsible for face recognition.

Separately from us, another group looked at brain activity, which is also correlated. The longer women take the pill, the greater its effect.

Face recognition should be included in studies that examined the influence of the contraceptive pill on memory. In fact, and with a considerable amount of circumspection, it could be said that the common denominator among the few available studies is that taking the contraceptive pill seems to slightly improve memory function.

This does not mean that taking the contraceptive pill is either good or bad, but merely that it may have an effect. As every woman reacts differently to using the pill and there are still very few relevant studies, it is not yet possible to make recommendations.

What were the findings on this topic in earlier studies?

Our hypotheses are based on findings concerning the effect of endogenous hormones on the brain. We have looked at a number of brain regions that have consistently responded to hormones in a similar way – across a variety of studies and in different test subjects. When estradiol levels rise, there is more gray matter and more activity in the hippocampus. As the pill usually contains a very strong synthetic estrogen (ethylene estradiol), we can expect a very similar effect. But this still has yet to be proven.

Note: estradiol is a sex hormone and the most effective natural estrogen (estrogen) in comparison with estrone and estriol. It is produced mainly in the ovarian follicles.

Thank you for this interview.

Also of interest:

How the brain distinguishes between voice and sound

Study using AI: men’s and women’s brains are different