生物谷报道：1月21日，美国研究人员在一项的新的研究结果中宣布，每天喝超过两杯咖啡的孕妇，和不摄入咖啡因的孕妇相比，其流产率要高上一倍。该报告发表在2008年1月在线版的《美国产科学与妇科医学杂志》上。
该研究有力的证据显示，无论是来自咖啡、茶、苏打水，还是热巧克力的咖啡因，每日过量摄入都导致流产的风险大大增加。过量摄入是指一天超过200毫克，即两杯咖啡的咖啡因含量。
Kaiser Permanente研究部的李德坤(De-Kun Li)博士说，这一结果证实了咖啡因和流产的相关性。孕妇或是希望怀孕的妇女，应该在三个月里停止饮用咖啡，最好是孕期都不要喝。
“这方面一直存在不确定。”李德坤在接受电话采访时说：“业界对此没有明确建议，即孕妇应该摄入多少咖啡因。”
李德坤表示，约15项到18项研究都证实了咖啡因和流产的相关性。但该组织表示，许多孕妇因咖啡因会导致恶心而放弃饮用，这可能会让结果有偏差。李德坤和同事们研究时努力避免出现这种偏差。从1996年10月到1998年10月，他们的研究包括Kaiser Permanente健康项目下的1063名孕妇。她们在怀孕期间没有改变自己的咖啡因摄入。
他们发现，那些日饮用超过两杯咖啡，或五罐12盎司、含咖啡因苏打水的妇女，比不摄入咖啡因的流产率高出一倍。这种危险似乎和咖啡因有关，而不是咖啡里的其他化学物质，因为当其他食品，如苏达水，茶和热巧克力中含咖啡因时，结果仍然类似。
李德坤称，一些研究者认为咖啡因有害，因为它会压迫胎儿不成熟的新陈代谢系统，也会减慢胎盘里的血循环，从而对胎儿造成损伤。”
“在我看来，不饮用才是最安全的。”李德坤说：“如果你真想喝咖啡，试着控制到一杯，最多一天两杯。”他也建议换成其他低咖啡因饮品。
以这一结果为依据，位于北加州的Kaiser Permanente女性健康机构主任特雷西・弗拉纳根(Tracy Flanagan)博士表示，孕妇应该将咖啡控制在一天一杯，她们也应考虑完全戒饮。
“很多流产的原因都不可控，”她在电话采访里说：“但这一点是能采取积极措施控制的。”
生物谷推荐英文原文：
American Journal of Obstetrics & Gynecology
The effect of caffeine consumption and nausea on the risk of miscarriage.
Giannelli M, Doyle P, Roman E, Pelerin M, Hermon C
Paediatr Perinat Epidemiol 2003; 17:316-23.
Abstract
Evidence for a harmful effect of caffeine intake on risk of miscarriage (spontaneous abortion) is inconsistent and nausea during pregnancy has been claimed to explain any association seen. The objective of this analysis was to determine whether caffeine consumption both before and during pregnancy influenced the risk of miscarriage in a group of pregnant women in the UK. We examined the association with maternal caffeine intake in a case-control study of 474 nulliparous women. Participants were recruited during the years 1987-89 from the Royal Berkshire Hospital in Reading and from a large group practice situated within the hospital's catchment area. Cases were 160 women with a clinically diagnosed miscarriage and controls were 314 pregnant women attending for antenatal care. Information on coffee/tea/cola consumption and potential confounders was collected by interview and caffeine content was assigned to individual drinks according to published data on caffeine content of beverages. Compared with a maternal caffeine intake of < 151 mg/day, we found evidence that caffeine consumption > 300 mg/day doubled the risk of miscarriage. Adjusted odds ratios were 1.94 [95% CI 1.04, 3.63] for 301-500 mg/day and 2.18 [95% CI 1.08, 4.40] for > 500 mg/day. This effect could not be explained by nausea in pregnancy. Nausea appeared to be strongly independently associated with a reduced risk of miscarriage (test for trend P < 0.0001). There was no evidence that prepregnancy caffeine consumption affected the risk. Our results indicate that high caffeine consumption during pregnancy (>300 mg/day), in particular coffee consumption, is an independent risk factor for increased risk and nausea is an independent protective factor for a lower risk of miscarriage.
MeSH
Abortion, Spontaneous; Adult; Beverages; Caffeine; Case-Control Studies; Coffee; Dose-Response Relationship, Drug; Female; Humans; Nausea; Preconception Care; Pregnancy; Risk Factors
