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作者：Laurie Barclay, MD  
出處：WebMD醫學新聞

　　May 26, 2010 — 根據線上發表於4月28日美國臨床營養期刊(American Journal of Clinical Nutrition)的世代研究結果，懷孕期間每天攝取超過6單位的咖啡因與胎兒身高不佳有關。
　　
　　荷蘭鹿特丹Erasmus醫學中心的Rachel Bakker與Generation R Study的研究夥伴寫道，咖啡因是廣為使用且被接受的一種藥物活性成分，懷孕期間攝取咖啡因對於胎兒身高和發育的影響還不清楚。
　　
　　研究目標是評估母親在懷孕各階段從咖啡及茶攝取咖啡因對於胎兒身高和不良生產結果的影響。從2001到 2005年，荷蘭共有7,346名孕婦從懷孕初期即參與一項以人口為基礎的世代研究。
　　
　　在懷孕第一、第二、第三期時，以問卷調查確認咖啡與茶的攝取量。然後進行一系列超音波檢查，以確認胎兒生長特徵，回顧病歷紀錄，以確認生產結果。
　　
　　在任一懷孕期，咖啡因攝取和胎兒頭圍或估計胎兒體重都沒有一致關聯。相對的，攝取較多咖啡因和第一懷孕期冠臀長較小、第二和第三懷孕期股骨長和身長較小有關(趨勢P值 < .05)。每天攝取至少6單位咖啡因的母親，嬰兒出生時體重小於妊娠年紀的風險增加。
　　
　　作者們寫道，我們的結果認為，懷孕期間每天咖啡因攝取≧6單位與胎兒身長不佳有關，咖啡因攝取可能先對於胎兒骨骼發育有不良影響，需要後續研究，以評估非歐洲人口的此項關連，並評估嬰兒出生後的結果。
　　
　　研究限制包括，觀察型研究設計，可能有其他干擾因素；關於咖啡和茶攝取量的資料有疏漏，導致研究強度減弱。
　　
　　研究作者們結論表示，似乎從懷孕第一期開始，身高或骨骼相關胎兒發育特徵就受到影響，需要後續的結構性和功能性研究，以評估其對特定器官的影響。我們的結果認為，應建議孕婦在懷孕期間每天的咖啡因攝取量不要≧6咖啡因單位(相當於0.540 mg)。
　　
　　鹿特丹Erasmus醫學中心、鹿特丹Erasmus大學、荷蘭健康研究與發展組織(ZonMw)提供財務支持第一階段的Generation R Study。研究作者之一接受荷蘭健康研究與發展組織之支持。
　　
　　Am J Clin Nutr. 線上發表於2010年4月28日。


High Caffeine Intake During Pregnancy Linked to Reduced Fetal Length

By Laurie Barclay, MD
Medscape Medical News

May 26, 2010 — Caffeine intake of 6 or more units per day during pregnancy is associated with impaired fetal length growth, according to the results of a cohort study reported online April 28 in the American Journal of Clinical Nutrition.

"Caffeine is a widely used and accepted pharmacologically active substance," write Rachel Bakker, from Erasmus Medical Center in Rotterdam, the Netherlands, and colleagues from the Generation R Study. "The effect of caffeine intake during pregnancy on fetal growth and development is still unclear."

The goal of the study was to evaluate the associations of maternal caffeine intake from coffee and tea with fetal growth measured during each trimester of pregnancy and with the risks for adverse birth outcomes. From 2001 to 2005, a total of 7346 pregnant women in the Netherlands participated in a population-based prospective cohort study from early pregnancy onward.

Questionnaires were used to determine coffee and tea consumption in the first, second, and third trimesters. Serial ultrasound studies allowed determination of fetal growth characteristics, and hospital record review allowed determination of birth outcomes.

A regular serving of 125 mL of coffee in the Netherlands contains approximately 90 mg of caffeine (caffeinated), decaffeinated coffee contains 3 mg, and tea contains 45 mg per 125-mL serving. This was used as the standard for calculation of daily caffeine consumption. Each unit of caffeine exposure was based on 1 cup of coffee (90 mg of caffeine), and total caffeine intake was categorized as less than 2 units, 2 to 3.9 units, 4 to 5.9 units, and 6 or more units per day.

Caffeine consumption was not consistently associated with fetal head circumference or with estimated fetal weight in any trimester. In contrast, higher caffeine consumption was associated with smaller first-trimester crown-rump length, second- and third-trimester femur length, and birth length (P for trend < .05). The risk of having a small-for-gestational-age infant at birth was increased in mothers who consumed at least 6 caffeine units per day.

"Our results suggest that caffeine intake of ?6 units/d during pregnancy is associated with impaired fetal length growth," the study authors write. "Caffeine exposure might preferentially adversely affect fetal skeletal growth. Further studies are needed to assess these associations in non-European populations and to assess the postnatal consequences."

Limitations of this study include observational design with possible residual confounding; and missing data on coffee and tea consumption, which may have led to loss of power.

"Length- or skeletal-related fetal growth characteristics seemed to be most consistently affected from the first trimester onward," the study authors conclude. "Further structural and functional studies are needed to assess organ-specific effects. Our results suggest that pregnant women should be advised to not consume ?6 caffeine units (.540 mg) per day during pregnancy."

The Erasmus Medical Center Rotterdam, the Erasmus University Rotterdam, and the Netherlands Organization for Health Research and Development (ZonMw) financially supported the first phase of the Generation R Study. One of the study authors was supported by the Netherlands Organization for Health Research.

Am J Clin Nutr. Published online April 28, 2010.