Fetal Medicine Research Institute, King's College London, London UK.
School of Population Health and Environmental Sciences, King's College London, London UK; National Institute for Health Research Biomedical Research Centre, London UK; Guy's and St Thomas' National Health Service Foundation Trust, London UK; King's College London, London UK.
Am J Obstet Gynecol. 2019 Sep;221(3):249.e1-249.e14. doi: 10.1016/j.ajog.2019.03.027. Epub 2019 Apr 2.
Parous women have a lower risk for pregnancy complications, such as preeclampsia or delivery of small-for-gestational-age neonates. However, parous women are a heterogeneous group of patients because they contain a low-risk cohort with previously uncomplicated pregnancies and a high-risk cohort with previous pregnancies complicated by preeclampsia and/or small for gestational age. Previous studies examining the effect of parity on maternal hemodynamics, including cardiac output and peripheral vascular resistance, did not distinguish between parous women with and without a history of preeclampsia or small for gestational age and reported contradictory results.
The objective of the study was to compare maternal hemodynamics in nulliparous women and in parous women with and without previous preeclampsia and/or small for gestational age.
This was a prospective, longitudinal study of maternal hemodynamics, assessed by a bioreactance method, measured at 11 to 13, 19 to 24, 30 to 34, and 35 to 37 weeks' gestation in 3 groups of women. Group 1 was composed of parous women without a history of preeclampsia and/or small for gestational age (n = 632), group 2 was composed of nulliparous women (n = 829), and group 3 was composed of parous women with a history of preeclampsia and/or small for gestational age (n = 113). A multilevel linear mixed-effects model was performed to compare the repeated measures of hemodynamic variables controlling for maternal characteristics, medical history, and development of preeclampsia or small for gestational age in the current pregnancy.
In groups 1 and 2, cardiac output increased with gestational age to a peak at 32 weeks and peripheral vascular resistance showed a reversed pattern with its nadir at 32 weeks; in group 1, compared with group 2, there was better cardiac adaptation, reflected in higher cardiac output and lower peripheral vascular resistance. In group 3 there was a hyperdynamic profile of higher cardiac output and lower peripheral vascular resistance at the first trimester followed by an earlier sharp decline of cardiac output and increase of peripheral vascular resistance from midgestation. The incidence of preeclampsia and small for gestational age was highest in group 3 and lowest in group 1.
There are parity-specific differences in maternal cardiac adaptation in pregnancy.
经产妇发生妊娠并发症（如子痫前期或小于胎龄儿分娩）的风险较低。然而，经产妇是一组异质性患者，因为她们包含低风险队列，这些患者之前的妊娠无并发症，也包含高风险队列，这些患者之前的妊娠合并子痫前期和/或小于胎龄儿。之前研究对子代产妇血液动力学（包括心输出量和外周血管阻力）的影响的研究没有区分有无子痫前期或小于胎龄儿史的经产妇，报告的结果相互矛盾。
本研究旨在比较初产妇与既往无子痫前期和/或小于胎龄儿史、有子痫前期和/或小于胎龄儿史的经产妇的母代血液动力学。
这是一项前瞻性、纵向研究，通过生物电阻抗法评估母代血液动力学，在 3 组女性中于 11 至 13 周、19 至 24 周、30 至 34 周和 35 至 37 周进行测量。第 1 组由既往无子痫前期和/或小于胎龄儿史的经产妇组成（n=632），第 2 组由初产妇组成（n=829），第 3 组由既往有子痫前期和/或小于胎龄儿史的经产妇组成（n=113）。使用多级线性混合效应模型，在控制母体特征、既往病史以及当前妊娠是否发生子痫前期或小于胎龄儿时，比较血液动力学变量的重复测量值。
在第 1 组和第 2 组中，心输出量随妊娠周数增加，在 32 周时达到峰值，外周血管阻力呈相反模式，在 32 周时达到最低点；与第 2 组相比，第 1 组的心脏适应性更好，表现为心输出量更高，外周血管阻力更低。第 3 组在孕早期表现出高动力状态，心输出量较高，外周血管阻力较低，随后从中孕期开始心输出量急剧下降，外周血管阻力增加。子痫前期和小于胎龄儿的发生率在第 3 组最高，在第 1 组最低。
妊娠时母体心脏适应性存在与产次相关的差异。
