Health: Oestrogen may be culprit in puzzle over PMT

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The Independent Online
Pre-menstrual tension is not all in the mind, but neither is it caused by high levels of sex hormones. Jeremy Laurance, health editor, says new findings about the puzzling syndrome could point the way to improved treatments.

The female hormone, oestrogen, may make some women ill, researchers have found. Although it has never before been seriously considered as a hormone with negative mood effects, there is now sufficient evidence to suggest it may be a cause of PMT. Millions of women suffer symptoms including depression, irritability and feelings of bloatedness up to two weeks before their periods. In one in 40, symptoms are severe enough to prevent sufferers going to work.

Many doctors were unsympathetic, labelling badly affected women as whingers. Part of the reason came from studies which failed to show any excess level of hormones in sufferers. Support for their view also appeared to come from studies which showed the most effective treatment for PMT was anti-depressants. Over 70 per cent of women with severe symptoms get better when treated with Prozac. But a study has shown the hormones oestrogen and progesterone are at least as important as the central neurotransmitters (brain chemicals) targeted by Prozac in producing the symptoms.

Researchers at the National Institutes of Health in Bethesda, Maryland, studied 20 women with severe PMT who were compared with 15 normal women. In the first part of the study, published in the New England Journal of Medicine, half the women with PMT were given a drug to suppress their ovaries. Their symptoms eased. They were then given, separately, synthetic progesterone and oestrogen. With the addition of each hormone, their symptoms returned. The remaining women with PMT and the normal women, who were treated with a placebo, did not experience a change in symptoms.

The most striking finding is that manipulation of the hormones had a dramatic effect on the PMT sufferers but none on the "normal" women. Blood tests showed hormone levels were the same in both groups. This suggests PMT is the result of a heightened sensitivity to the normal hormonal changes accompanying menstruation and is not caused by excessive levels of hormones.

In an editorial in the journal, Joseph Mortola, of Cook County Hospital, Chicago, says PMT is "probably the result of a complex interaction between ovarian steroids [hormones] and central neurotransmitters."

He says the finding that giving progesterone caused the return of symptoms in PMT sufferers who had had their ovaries suppressed could have been expected from other studies but the finding that oestrogen had the same effect was surprising. The paradox is that most women with PMT report easing of their symptoms during the early follicular phase of the menstrual cycle when oestrogen levels are at their highest. If oestrogen is proved to play a part in development of the syndrome, "it could prompt the development of entirely new treatment strategies based on drugs or hormones with anti- oestrogenic properties".