準媽媽每天需攝入最少400微克葉酸
故此，懷孕期進食適量葉酸（1000 微克以下）有助減低嬰幼兒日後出現自閉症的機會，更能減低胎兒神經管缺陷、減低小產機率及增加試管嬰兒成功率。
故此醫生建議，準媽媽（包括計劃懷孕及孕婦）不要一刀切戒高葉酸食物，或者含葉酸的補充劑，因為吸收不足對胎兒的影響，遠遠大於吸收過量。
孕婦及計劃懷孕的女性每天需進食至少 400 微克的葉酸，因為單靠日常進食，未足以應付身體每日所需，應按醫護人員的指示揀選及服用補充劑，切忌胡亂在坊間自行購買多種補充劑混合服用，以免進食過量。
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