Impact of continuing folic acid after the first trimester of pregnancy: findings of a randomized trial of Folic Acid Supplementation in the Second and Third Trimesters
Impact of continuing folic acid after the first trimester of pregnancy: findings of a randomized trial of Folic Acid Supplementation in the Second and Third Trimesters
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DOI：
10.3945/ajcn.112.057489
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发表时间：
2013-07-01
影响因子：
7.1
通讯作者：
Pentieva, Kristina
中科院分区：
文献类型：
--
作者：
McNulty, Breige;McNulty, Helene;Pentieva, Kristina
背景：世界范围内建议在妊娠前和妊娠早期补充叶酸（FA），因为其预防神经管缺陷的作用已被证实，但 FA 在妊娠第 12 周（GW）后的作用还不太清楚。目的：我们调查了妊娠前三个月后持续补充 FA 对孕妇叶酸和同型半胱氨酸的反应以及对新生儿的相关影响。设计：孕妇，年龄 18-35 岁，正在参加产前检查北爱尔兰诊所的单胎无并发症妊娠并报告在妊娠前三个月服用 FA 补充剂，在妊娠 2 开始时被随机分配接受 400 微克 FA/天或安慰剂胶囊。 结果：共有 119 名女性（安慰剂组 60 名女性；治疗组 59 名女性）完成了试验。从GW 14-36开始，未补充补充剂的女性平均（+/- SD）血清叶酸下降（从45.7 +/- 21.3至19.5 +/- 16.5 nmol/L；P < 0.001），而血浆同型半胱氨酸增加（6.6 +/- 2.3至7.6 +/- 2.3 mu mol/L；P < 0.001）。然而，补充 FA 可阻止这些变化，并导致红细胞叶酸浓度从 1203 +/- 639 显着增加至 1746 +/- 683 nmol/L（P < 0.001；GW 14-36）。 FA 组的脐带血叶酸显着高于安慰剂组（红细胞浓度分别为 1993 +/- 862 和 1418 +/- 557 nmol/L；P = 0.001）。 结论：在妊娠第 2 和第 3 三个月持续补充 400 μg FA/d 可以提高母体和脐带血叶酸状态，并防止同型半胱氨酸浓度升高。在怀孕后期。这些影响是否对妊娠结局或幼儿期有好处还需要进一步研究。
Background: Supplementation with folic acid (FA) is recommended worldwide before and during early pregnancy because of its proven effect in preventing neural tube defects, but the role of FA after the 12th gestational week (GW) is much less clear.Objective: We investigated maternal folate and homocysteine responses and related effects in the newborn that resulted from continued FA supplementation after the first trimester of pregnancy.Design: Pregnant women, aged 18-35 y, who were attending an antenatal clinic in Northern Ireland with singleton uncomplicated pregnancies and reported taking FA supplements in the first trimester, were randomly assigned at the start of trimester 2 to receive 400 mu g FA/d or a placebo capsule.Results: A total of 119 women (60 women in the placebo group; 59 women in the treatment group) completed the trial. From GWs 14 36, mean (+/- SD) serum folate decreased (from 45.7 +/- 21.3 to 19.5 +/- 16.5 nmol/L; P < 0.001) in unsupplemented women, whereas plasma homocysteine increased (6.6 +/- 2.3 to 7.6 +/- 2.3 mu mol/L; P < 0.001). However, FA supplementation prevented these changes and resulted in a significant increase in red blood cell folate concentrations from 1203 +/- 639 to 1746 +/- 683 nmol/L (P < 0.001; GWs 14-36). Cord blood folate was significantly higher in the FA group than in the placebo group (red blood cell concentrations of 1993 +/- 862 and 1418 +/- 557 nmol/L, respectively; P = 0.001).Conclusions: Continued supplementation with 400 mu g FA/d in trimesters 2 and 3 of pregnancy can increase maternal and cord blood folate status and prevent the increase in homocysteine concentration that otherwise occurs in late pregnancy. Whether these effects have benefits for pregnancy outcomes or early childhood requires additional study.