A study found that women on the pill prefer men who look more feminine. Photo: Shutterstock

A recent study found that women taking oral contraceptives are attracted to faces that look less masculine. Anthony Little and colleagues found that after about three months on the ‘pill’, women started to prefer men who look more feminine.

Craig Roberts, of the University of Stirling, and others have recently reviewed a growing body of research showing that the choice of partner a woman makes changes through the menstrual cycle.

At the time of ovulation, when a woman is most fertile, she prefers a more masculine and genetically-unrelated man. The ‘pill’ removes this natural preference and women on the pill instead demonstrate a preference for men with more feminine facial appearance and voice.

Roberts says that these studies taken together show that oral contraceptives alter women’s mate preference judgements. They have the potential to influence the partner that a single woman chooses. If a woman stops using oral contraceptives her attraction to her partner may also alter.

A further factor that could affect the stability of marriage is that partnered women report higher levels of jealousy when on the ‘pill’. This was recently reported in the journal Evolution and Human Behaviour by Kelly Cobey and colleagues.

Oral contraceptive use could ultimately affect the stability of relationships.

It is possible that these factors could explain a link between the contraceptive pill and divorce.

Oral contraceptive use could affect the stability of relationships

The contraceptive pill was first marketed in 1960 and, by 1965, 26 per cent of married women in the USA had used it. The divorce rate started to increase about five years later and doubled from 25 per cent to 50 per cent, between 1965 and 1975 (see figure).

In 1978, Robert Michael, of Stanford University, showed that contraceptive use accounted for 45 per cent of the increase in divorce. These new data make further research on the link between divorce and the ‘pill’ essential and urgent.

Neurobiological research is beginning to reveal that oral contraceptives produce alterations in several fundamental brain processes. For example, combined oral contraceptives alter sexual desire in 23 per cent of users (15 per cent decreased and eight per cent increased). Also, about 10 per cent of women on the pill have disturbances of mood, like depression, and it was found that, in these women, the normal response to emotion is decreased in some brain areas on functional brain imaging.

We are increasingly finding out that oral contraceptives have widespread effects on brain pathways, quite apart from their direct effects on the body.

The fact that the pill is taken regularly on a daily basis for a long period of time means that a woman’s behaviour is effectively altered over a very important part of her live emotionally, a time when she is making choices about a lifelong partner.

Since the brain pathways affected include those that are central to mate preference and emotional learning, there is a danger that use of the ‘pill’ may negatively influence the choice of partner.

It is important that women are fully educated about these effects of the oral contraceptive and the potentially-devastating effects they could have on their lives.

Patrick Pullicino is professor of clinical neurosciences at the University of Kent.