An evolutionary psychologist at the University of Groningen claims that using hormonal contraceptive pills can significantly affect and intensify feelings of jealously in women.

Kelly Cobey has found that women in stable relationships experience increased levels of jealousy while being on the Pill. She also discovered that male partners tend to find women more attractive when they are not on the Pill.

What does the Pill change?

The Pill is designed to regulate a woman’s natural fertility cycle and, of course, prevent pregnancy. When a woman is not using the Pill, she might experience a change in herpartner preference or behaviour when she is in her fertile window.

As this is suspected to be due to hormone fluctuations, this change is thus suppressed in any woman who is taking oral birth control.

The method

As the researcher could accurately determine fertile and non-fertile times in women, subjects were able to answer questions about how they felt at very specific periods during their cycle. They were then monitored while they were using the Pill.

Their male partners were also asked to monitor their behaviour and relationship dynamic, in order to test for the effects of both the natural cycle and the Pill on their perceptions of their relationship.

Results for women

The study showed that women who are not on the Pill are more jealous mid-cycle. This was found to occur regardless of age or relationship status and in different cultures.

Interestingly, while the women were using the Pill they experienced levels of jealousy comparable with the jealously levels they experienced during the fertile part in their natural cycle.

There was also a correlation found between increased jealousy and the use of oral contraceptives with higher doses of synthetic oestrogen. These pills in particular might affect intimate relationships through jealousy-induced changes in behaviour.

Cobey concluded that any change in Pill use during a relationship is likely to increase the risk of higher levels of jealousy.

Results for men

Several studies have found that men find women more attractive when they are in the fertile part of their cycle, a finding also demonstrated in this study. Furthermore, the study discovered that men find their partners less attractive when they are on the Pill.

She also found that men considered themselves more attractive when their partners are naturally cycling.

Relevance

Cobey said that the birth control pill has proven its value as a social instrument and that because of its benefits, women are prepared to put up with minor negative consequences.

What she wants to see change, however, is the fact that women are rarely briefed by their doctors on the Pill's subtle effects that influence relationships and behaviour.

She wants doctors to pay more attention to these effects and consider them when advising patients about birth control.

Source: University of Groningen