Affectionate couple
It was meant to revolutionise life in the bedroom - but taking the Pill switches off the look of love. A new study shows that women who choose the daily contraceptive see their men in a less flattering light.

Kissing and cuddling trigger the release of oxytocin - the so-called love hormone - which sparks reward activity in the brain and makes partners appear more attractive to each other. However, researchers from Bonn University in Germany have discovered that the Pill shuts down the besotted response.

The team recruited forty women in their twenties and loving long-term relationships, half of whom were taking hormonal contraceptives. Some were given an oxytocin boost using a nasal spray while the rest were administered a placebo. Then they were shown a series of photos featuring their partner, a close female friend and similar-looking strangers of both sexes. The women were asked to rate them all out of 100 for attractiveness while brain scans kept watch on their mental responses to the pictures.

Lovers topped the poll in every case, though the oxytocin boost came into play too. Husbands and boyfriends whose partners had taken the spray but not the Pill outscored male strangers by an extra ten per cent. The same sub-group of women experienced far more activity in the nucleus accumbens - the part of the brain which deals with pleasure and emotional arousal - when photos of their lovers flashed up. However, for those on the Pill, oxytocin caused the region to light up more when pictures of their friends were shown.

The study - published in Social, Cognitive and Affective Neuroscience - states: 'Treatment with oxytocin increased the perceived attractiveness of the partner relative to other men, which was paralleled by elevated responses in reward-associated regions, including the nucleus accumbens. 'These effects were absent in women using hormonal contraceptives.' It adds: 'To some extent [the Pill] mimics hormone profiles during pregnancy, [so] oxytocin may increase the reward value of a female friend as a potential source of social support.'

Previous research has shown that oxytocin levels are higher in new lovers compared with single people. Among men already in a relationship, the hormone has been shown to deter flirting with strangers and to increase the attractiveness of wives or girlfriends.

The study says: '[It appears that] oxytocin interacts with the brain reward system to reinforce partner value representations in both sexes, a mechanism which may significantly contribute to stable pair-bonding in humans and appears to be altered in women using hormonal contraceptives.'

Psychosexual therapist Pauline Brown said the research presents women with a dilemma. She said: 'There's no doubt that the Pill lowers the libido in many women and this explains why. 'It's a paradox that contraception can be seen by some couples as a way to help their relationship and yet it may end up having the opposite effect.

'There is nearly always more than one reason why a couple seeks therapy, but the Pill's dampening of libido is often one of the factors putting pressure on a relationship. 'Sometimes, simply changing the method of contraception can have a significant effect.
'Oxytocin is such a powerful hormone and is part of what it means to be alive and a human being. 'The more we know about how it affects our behaviour and the brain, the better the decisions people will be able to take for themselves.'

The Pill was introduced to the UK in 1961. It contains excesses of the hormones oestrogen and progesterone which lead the body to stop the ovulation process.