咖啡喝過量 婦女「孕」藏危機

Carl

http://www.libertytimes.com.tw/2008/new/jul/9/today-life4.htm

〔編譯張沛元／綜合報導〕英國廣播公司（ＢＢＣ）新聞網七日報導，荷蘭的一份研究暗示，喝太多咖啡恐降低有不孕問題婦女的自然受孕率。

日飲逾4杯 受孕率降26％

荷蘭奈美根拉德邦大學研究人員針對從一九八五年到一九九五年所有在荷蘭做過試管嬰兒的九千名婦女進行研究，結果發現，其中七分之一的確自然懷孕，但每天喝超過四杯咖啡者的受孕率降低約二十六％。專家指出，該研究結果僅適應於生殖力差、想提高受孕機率的婦女。

研究結果顯示，十六％的婦女最後自然懷孕，四十五％在做了最後一次試管嬰兒的六個月內懷孕；研究人員透過問卷分析生活方式對受試婦女懷孕的影響程度，發現一週至少喝酒三次跟大量喝咖啡一樣，都會降低受孕率。不過，一天抽菸超過一支以及體重過重對降低受孕率的影響更大。

研究人員估計，一名三十六歲的抽菸、攝取很多酒精與咖啡因、體重超重、已做過三次試管嬰兒的婦女，其自然懷孕機率僅五％；但倘若她的體重正常，不抽菸或不攝取那麼多咖啡因與酒精，其自然懷孕機率為十五％。

研究領導人李斯頓在歐洲人類生殖與胚胎學學會於巴塞隆納召開的會議上表示，醫生必須提醒病患，做過試管嬰兒後，維持健康的生活方式有助於提高自然受孕率。

Coffee 'worsens poor fertility'

Too much coffee can reduce the chances of a woman with fertility problems getting pregnant, a study suggests.

Dutch researchers followed 9,000 women who had received IVF to see if they fell pregnant naturally.

Around one in seven did, but drinking more than four cups of coffee a day cut chances of conceiving by around 26%.

Experts said the findings, presented to a European conference, only applied to women with poor fertility who wanted to maximise their chances of pregnancy.

The researchers, from Radboud University in Nijmegan, studied all women who had received IVF treatment in the Netherlands between 1985 and 1995.

They found 16% of the women went on to conceive naturally, 45% within six months of their last IVF treatment.

They used questionnaires to analyse how lifestyle factors affected a woman's chances of pregnancy.

Drinking alcohol at least three times a week carried the same risk as excessive caffeine intake.

But smoking more than one cigarette a day and being overweight reduced the chances of pregnancy even more.

The researchers estimated that a 36-year-old woman who smoked, drank too much coffee and alcohol and was overweight, and who had been through three cycles of IVF, would have a 5% chance of a natural pregnancy.

If she was a healthy weight and did not smoke or have too much caffeine or alcohol, her chance would be 15%.

'Limitations'

Dr Bea Linsten, who led the research, told the European Society for Human Reproduction and Embryology conference in Barcelona that patients should be advised how they can maximise their chances of a natural pregnancy.

"We have to remind our patients that they may influence their chance of spontaneous pregnancy after IVF with a healthy lifestyle."

However, some experts warned that the findings of the study had to be examined with caution.

Fiona Ford, of the Centre for Pregnancy Nutrition, said: "Whilst the results of this study are interesting, there are evidently limitations to these findings as post IVF patients are a selective group who have already experienced problems with conception.

"There is nothing within this study that provides a reason to change guidance to patients."

She cited previous reseach which said there was no "convincing support" for the claim that coffee was linked to delayed conception.

Fertility expert Professor Bill Ledger, from the University of Sheffield, said caffeine could potentially have a mild, but toxic, effect on ovaries and sperm which could be a problem for those with poor fertility.

But he added: "A lot of women can have 20 cups of coffee a day and get pregnant while falling off a log, but if you're already subfertile it could push you over the edge.

"It is only a problem if you are subfertile and you overdose."

Zoe Wheeldon, from the British Coffee Association, said: "There is no need to cut caffeine or coffee out of the diet completely, scientific evidence demonstrates that for pregnant women or those trying to conceive up to 300mg of caffeine per day is perfectly safe."