RANDOMIZED CALCIUM TRIAL IN HIGH RISK PREGNANCIES

高风险妊娠的随机钙试验

• 批准号: 2673801
• 负责人: JORGE A PRADA
• 金额: $ 32.12万
• 依托单位: UNIVERSITY OF CINCINNATI
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-09-10 至 2000-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2673801
• 关键词: 1,25 dihydroxycholecalciferol; adolescence (12-20); age at pregnancy; atomic absorption spectrometry; blood pressure; bone metabolism; calcium metabolism; clinical chemistry; clinical trials; collagen; dietary calcium; dietary supplements; human pregnant subject; longitudinal human study; nutrient requirement; nutrition related tag; osteocalcin; parathyroid hormones; parity; pregnancy; radioimmunoassay; statistics /biometry; urinalysis; women's health; young adult human (21-34)

According to the US. Food and Nutrition Board, the Recommended Daily Allowance (RDA) of calcium during pregnancy is 1200 mg/day. The RDA for the adolescent during the growing years is also 1200 mg/day. There is no recommendation for an increment in calcium intake to meet the presumably greater calcium needs of pregnant adolescents or for multiple gestation pregnancies: specifically calcium and bone metabolism changes during these higher risk pregnancies, and the effect of calcium intake on maternal calcium and bone metabolism are unclear. Recent studies suggest that conventional dietary calcium intake during pregnancy may be inadequate to maintain a positive calcium balance and optimal bone metabolism, and several studies have also demonstrated a direct relationship between low calcium status and higher incidence of hypertension during pregnancy which may lead to a significant neonatal morbidity. Theoretically, calcium imbalances may occur when there is a need for high fetal calcium accretion, such as in adolescent pregnancy, and also in multiple gestation, because pregnancy occurs during the period of active maternal bone growth. The overall objective of this longitudinal randomized trial is to determine whether there are significant alterations in maternal serum calcium, calcium regulatory hormone, and bone mass indices during adolescent pregnancy and adult multiple gestation, and whether these changes are influenced by dietary calcium intake. The hypotheses to be tested are: l) there is a greater need for calcium and a greater increase in serum calcium regulatory hormone concentration (PTH and calcitriol), among adolescent pregnancies and adult multiple gestations compared to adult singleton pregnancy; and, 2) pregnant adolescents and females with multiple gestation who are randomized to receive calcium supplement (1000 mg/day) will have less of a decrease in serum calcium, and less of an increase in serum PTH and calcitriol throughout pregnancy compared to similar women randomized to placebo. Changes in biochemical indicators of bone metabolism (Osteocalcin, serum carboxyterminal propeptide, and serum cross-linked telopeptide of type I collagen) also will be investigated. The trial will be conducted in 336 pregnant women. Participants will include healthy pregnant females between 21 and 40 years of age, with singleton and multiple gestations, and singleton mothers age 12 to 20 years. This study will aid in the understanding of calcium and bone metabolism and calcium requirements in adolescent pregnancy and adult multiple gestation; and may help in the understanding of the pathophysiology of hypertension during pregnancy.

据美国。食品和营养委员会，每日推荐 怀孕期间钙的允许摄入量（RDA）为1200 mg/天。的RDA 青少年在成长期也是1200毫克/天。没有 建议增加钙的摄入量，以满足可能的 怀孕青少年或多胎妊娠需要更多的钙 怀孕：特别是钙和骨代谢的变化， 这些高危妊娠，以及钙摄入量对 母体钙和骨代谢尚不清楚。最近的研究表明 怀孕期间常规的膳食钙摄入量可能 不足以维持积极的钙平衡和最佳的骨骼 代谢，一些研究也表明， 低钙状态与高发病率之间的关系 妊娠期高血压可能导致新生儿 发病率从理论上讲，钙失衡可能会发生时， 需要高的胎儿钙积累，如在青少年怀孕， 多胎妊娠也是如此，因为怀孕发生在 母亲骨生长活跃的时期。本报告的总体目标 纵向随机试验是为了确定是否有 母体血清钙、钙调节 激素和骨量指数在青春期怀孕和成人 多胎妊娠，以及这些变化是否受到饮食的影响 钙摄入量要检验的假设是：l）存在较大的 需要钙和更大的增加血清钙调节 少女怀孕期间的激素浓度（甲状旁腺激素和骨化三醇） 成人多胎妊娠与成人单胎妊娠相比;以及， 2)怀孕的青少年和多胎妊娠的女性， 随机接受钙补充剂（1000 mg/天）的患者， 血清钙降低，血清PTH增加较少， 骨化三醇在整个妊娠期间与随机分配至 安慰剂骨代谢生化指标的变化 骨钙素、血清羧基末端前肽和血清交联 I型胶原的端肽）也将被研究。审判将 在336名孕妇中进行。参与者包括健康 年龄在21至40岁之间的怀孕女性， 多胎妊娠和12至20岁的单胎母亲。本研究 将有助于了解钙和骨代谢和钙 青少年怀孕和成年多胎妊娠的要求;以及 可能有助于理解高血压的病理生理学 孕期