Bovbjerg Marit L, Siega-Riz Anna Maria, Evenson Kelly R, Goodnight William
College of Public Health and Human Sciences, Oregon State University, Corvallis, OR.
J Phys Act Health. 2015 Jan;12(1):37-47. doi: 10.1123/jpah.2012-0498. Epub 2014 Feb 5.
Previous studies report conflicting results regarding a possible association between maternal physical activity (PA) and cesarean delivery.
Seven-day PA recalls were collected by telephone from pregnant women (n = 1205) from North Carolina, without prior cesarean, during 2 time windows: 17 to 22 weeks and 27 to 30 weeks completed gestation. PA was treated as a continuous, nonlinear variable in binomial regressions (log-link function); models controlled for primiparity, maternal contraindications to exercise, preeclampsia, pregravid BMI, and percent poverty. We examined both total PA and moderate-to-vigorous PA (MVPA) at each time. Outcomes data came from medical records.
The dose-response curves between PA or MVPA and cesarean risk at 17 to 22 weeks followed an inverse J-shape, but at 27 to 30 weeks the curves reversed and were J-shaped. However, only (total) PA at 27 to 30 weeks was strongly associated with cesarean risk; this association was attenuated when women reporting large volumes of PA (> 97.5 percentile) were excluded.
We did not find evidence of an association between physical activity and cesarean birth. We did, however, find evidence that associations between PA and risk of cesarean may be nonlinear and dependent on gestational age at time of exposure, limiting the accuracy of analyses that collapse maternal PA into categories.
先前的研究报告了关于孕产妇身体活动（PA）与剖宫产之间可能存在的关联的相互矛盾的结果。
通过电话收集了北卡罗来纳州1205名未进行过剖宫产的孕妇在两个时间段（妊娠17至22周和27至30周）的7天PA回忆情况。在二项式回归（对数链接函数）中，PA被视为连续的非线性变量；模型控制了初产情况、孕产妇运动禁忌、先兆子痫、孕前体重指数和贫困百分比。我们在每个时间段都检查了总PA和中等到剧烈PA（MVPA）。结局数据来自医疗记录。
17至22周时PA或MVPA与剖宫产风险之间的剂量反应曲线呈倒J形，但在27至30周时曲线反转呈J形。然而，只有27至30周时的（总）PA与剖宫产风险密切相关；当排除报告大量PA（>第97.5百分位数）的女性时，这种关联减弱。
我们没有发现身体活动与剖宫产之间存在关联的证据。然而，我们确实发现有证据表明，PA与剖宫产风险之间的关联可能是非线性的，并且取决于暴露时的孕周，这限制了将孕产妇PA分为几类的分析的准确性。
