Obesity on Vagal Tone and HbA1c during Pregnancy

描述（由申请人提供）：肥胖是导致许多不良妊娠结局的原因，因此对妇女及其子女的健康有很大影响。据推测，与非肥胖女性相比，肥胖女性在怀孕期间HbA1c升高，迷走神经反应和氧合降低。来自四个主要民族的40名孕妇将在妊娠20周、28周和36周分别进行三次30分钟的观察，其中20名孕妇的肥胖和非肥胖状态由她们的体重指数决定。选择观察的时间点是因为20周后的胎儿如果出生就可以存活；在28周时，胎儿如果出生将是早产，在这个阶段，随着妊娠压力和妊娠体重增加，孕妇的高血压或糖尿病等疾病可能在临床上变得明显；在36周时，胎儿将接近足月分娩。妊娠并发症和婴儿结局将随后进行图表审核和受试者访谈。暂定分析计划将包括描述性统计、两组比较的t检验和重复测量方差分析，以检验随时间变化的组差异。将进行相关性和回归分析，以检查肥胖和妊娠体重增加水平与迷走神经反应、糖化血红蛋白、氧合、妊娠并发症和分娩结局的关系。如果效应量为1，则需要17个受试者才能检测到80%的差异。考虑到20%的流失率，如早产可能发生的，建议每组20名妇女。

DESCRIPTION (provided by applicant): Obesity is the cause of many adverse pregnancy outcomes and as a result, has a great impact on the health of women and their children. It is hypothesized that during pregnancy obese women will have increased HbA1c, decreased vagal response and oxygenation compared to non-obese women. Forty pregnant women of four major ethnic groups will be observed three times for 30 minutes at 20, 28, and 36 weeks gestation, 20 each with obese and non-obese status determined by their body mass index. The time points for observation have been selected because after 20 weeks the fetus could be viable if born; at 28 weeks the fetus if born would be preterm and at this stage, maternal disorders such as hypertension or diabetes may become clinically apparent with the stress of pregnancy and gestational weight gain; and at 36 weeks the fetus will be close to term birth. Pregnancy complications and infant outcomes will be followed by chart audits and interviews of subjects. The tentative analysis plan will include descriptive statistics, t-tests for two group comparisons, and, repeated measures ANOVA to test the group differences with changes over time. Correlations and regression analyses will be performed to examine the association of obesity and levels of gestational weight gain on vagal response, HbA1c, oxygenation, and pregnancy complications and birth outcomes. For an effect size of 1, 17 subjects will be needed to detect a difference with a power of 80%. Considering a 20% attrition rate, as may occur with preterm birth, 20 women per group is proposed.