Obesity on Vagal Tone and HbA1c during Pregnancy

描述（由申请人提供）：肥胖是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，妊娠期间肥胖女性的HbA 1c升高，迷走神经反应和氧合降低。来自四个主要种族的40名孕妇将在妊娠20周、28周和36周时观察三次，每次30分钟，根据体重指数确定肥胖和非肥胖状态各20名。选择观察时间点是因为20周后，如果出生，胎儿可以存活; 28周时，如果出生，胎儿将是早产，在这个阶段，母体疾病（如高血压或糖尿病）可能随着妊娠应激和妊娠期体重增加而变得临床明显; 36周时，胎儿将接近足月分娩。妊娠并发症和婴儿结局将通过图表审核和受试者访谈进行随访。暂定分析计划将包括描述性统计量、两组比较的t检验和重复测量ANOVA，以检验随时间变化的组差异。将进行相关性和回归分析，以检查肥胖和妊娠期体重增加水平与迷走神经反应、HbA 1c、氧合、妊娠并发症和出生结局的相关性。如果效应量为1，则需要17名受试者才能检测到80%把握度的差异。考虑到早产可能发生的20%的损耗率，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.