Randomized trial of vitamin B12 in pregnant Indian women

描述（由申请人提供）：在印度，胎儿生长不良和不良母婴结局的发生率相当高，有几条证据表明，母亲的营养状况可能是一个重要因素。我们之前对其他环境中不良的胎儿和婴儿结局进行了广泛的评估，发现艾滋病毒阳性的坦桑尼亚母亲补充微量营养素（B族维生素，包括维生素B12，加上维生素C和E）可使低出生体重（<2500 g）的风险降低44% (RR (95% Cl) 0.56(0.38-0.82))，严重早产（<34周妊娠）的风险降低39% (RR 0.61(0.38-0.96))，出生时胎龄小的风险降低43% （RR 0.57(0.39-0.82)）。在一项对410名印度孕妇的前瞻性队列研究中，我们最近发现孕妇血清维生素B12浓度与婴儿宫内生长迟缓（IUGR）风险之间存在密切关系。在控制了母亲的年龄、体重、教育程度和胎次后，与血清B12浓度最高胎位的妇女相比，最低胎位的妇女更有可能生下IUGR婴儿(OR （95% Cl) 5.98(1.72-20.74)）。我们现在提议在300名印度孕妇中进行一项随机、双盲试验，以确定维生素B12补充（每天50微克）在改善孕妇B12状态方面的有效性。该探索性试验的次要目标包括母体血红蛋白、孕期母体体重增加和婴儿出生体重。所有妇女将接受标准的产前产科护理，包括常规补充铁和叶酸。这项研究将由印度班加罗尔圣约翰研究所营养学部和美国波士顿哈佛大学公共卫生学院营养系共同努力。这项计划研究的结果将用于设计和开展更大规模、更明确的临床试验，正如我们在其他地方成功进行的那样。作为营养、儿科、流行病学和妇幼保健领域的专家，我们的小组致力于进一步评估微量营养素在改善印度妇幼保健结果方面可能发挥的作用。

DESCRIPTION (provided by applicant): The incidence of poor fetal growth and adverse maternal and infant birth outcomes is quite high in India, and several lines of evidence suggest that maternal nutritional status may be an important factor. We have previously performed extensive evaluations of poor fetal and infant outcomes in other settings, and found that maternal micronutrient supplementation (B vitamins including vitamin B12, plus vitamins C and E) in HIV positive Tanzanian mothers decreased the risk of low birthweight (<2500 g) by 44% (RR (95% Cl) 0.56 (0.38-0.82)), severe preterm birth (<34 weeks of gestation) by 39% (RR 0.61 (0.38-0.96)), and small size for gestational age at birth by 43% (RR 0.57 (0.39-0.82)). In a prospective cohort study of 410 pregnant Indian women, we recently found a strong relationship between maternal serum vitamin B12 concentration and risk of infant intrauterine growth retardation (IUGR). Compared to women in the highest tertile of serum B12 concentration, women in the lowest tertile were significantly more likely to have IUGR infants, after controlling for maternal age, weight, education, and parity (OR (95% Cl) 5.98 (1.72-20.74)). We now propose a randomized, double-blind trial among 300 pregnant Indian women in order to determine the effectiveness of vitamin B12 supplementation (50 ug daily) in improving maternal B12 status. Secondary aims for this exploratory trial include maternal hemoglobin, maternal weight gain during pregnancy and infant birthweight. All women will receive standard of prenatal obstetric care, including routine supplementation with iron and folate. The study will be a collaborative effort between the Division of Nutrition, St John's Research Institute, Bangalore, India, and the Department of Nutrition, Harvard School of Public Health, Boston, US. Findings from this planned study will be used to design and carry out a larger, more definitive clinical trial, as we have successfully performed elsewhere. As experts in the fields of nutrition, pediatrics, epidemiology and maternal and child health, our team is committed to further evaluating the possible role of micronutrients in improving maternal and child health outcomes in India.