Espinoza Jimmy, Kusanovic Juan Pedro, Kim Chong Jai, Kim Yeon Mee, Kim Jung-Sun, Hassan Sonia S, Gotsch Francesca, Gonçalves Luis F, Erez Offer, Friel Lara, Soto Eleazar, Romero Roberto
Perinatology Research Branch, NICHD/NIH/DHHS, Bethesda, MD, USA.
Am J Obstet Gynecol. 2007 Jun;196(6):574.e1-5; discussion 574.e5-6. doi: 10.1016/j.ajog.2007.03.023.
Patients with an episode of preterm labor that subsides in response to tocolysis and who, subsequently, deliver at term are considered to have false preterm labor. However, the episode of "preterm labor" may represent the uterine response (ie, uterine contractions) to an insult not severe enough to trigger preterm parturition, but which may put the fetus at risk for additional pregnancy complications, including growth restriction. The objective of this study was to compare the frequency of small-for-gestational-age (SGA) neonates among patients with an episode of increased uterine contractility who delivered at term and those who delivered preterm.
This retrospective cohort study included 849 patients. Inclusion criteria were (1) regular uterine contractions that required hospitalization, (2) intact membranes, and (3) gestational age between 20 and 36 weeks. SGA was defined as a birth weight of <10th percentile for gestational age. Placental pathologic evidence was reviewed, and the results were used to classify patients into an inflammatory cluster, vascular cluster, or both. Contingency tables, Mann-Whitney U test, and multivariate logistic regression were used for statistical analyses. A probability value of <.05 was considered significant.
The prevalence of SGA neonates in the study population was 16.1% (124/772). Patients who delivered at term had a significantly higher frequency of SGA neonates than those who delivered preterm (21.5% [64/298] vs 12.7% [60/474]; P = .001); the results of placental pathologic evidence were available in 63.7% (492/772) of the patients. Patients who delivered at term had a higher frequency of fetal or maternal vascular lesions without histologic evidence of inflammation than those who delivered preterm (29.1 % [43/148] vs 18.9% [65/344]; P = .01). Term delivery after an episode of regular preterm uterine contractions was associated with an odds ratio of 2.22 (95% CI, 1.28-3.85) to deliver an SGA neonate after the statistics were controlled for confounding variables. A subanalysis limited to patients who received tocolysis showed similar results.
Patients with an episode of increased uterine contractility that subsided and who deliver at term are at risk for delivering an SGA neonate, which suggests that an episode of false preterm labor is not a benign condition. We propose that insults to the fetoplacental unit may be resolved by either irreversible preterm parturition or restriction of fetal growth.
因宫缩抑制剂治疗而消退的早产发作患者，随后足月分娩者被认为是假性早产。然而，“早产发作”可能代表子宫对一种尚不严重到足以引发早产，但可能使胎儿面临包括生长受限在内的更多妊娠并发症风险的损伤的反应。本研究的目的是比较足月分娩的子宫收缩增强发作患者与早产患者中小于胎龄（SGA）新生儿的发生率。
这项回顾性队列研究纳入了849例患者。纳入标准为：（1）需要住院治疗的规律子宫收缩；（2）胎膜完整；（3）孕龄在20至36周之间。SGA定义为出生体重低于孕龄的第10百分位数。对胎盘病理证据进行了回顾，并将结果用于将患者分为炎症组、血管组或两者兼具组。使用列联表、Mann-Whitney U检验和多因素逻辑回归进行统计分析。概率值<0.05被认为具有统计学意义。
研究人群中SGA新生儿的患病率为16.1%（124/772）。足月分娩的患者中SGA新生儿的发生率显著高于早产患者（21.5%[64/298]对12.7%[60/474]；P = 0.001）；63.7%（492/772）的患者有胎盘病理证据结果。足月分娩的患者中无炎症组织学证据的胎儿或母体血管病变发生率高于早产患者（29.1%[43/148]对18.9%[65/344]；P = 0.01）。在对混杂变量进行统计学控制后，规律早产子宫收缩发作后足月分娩与分娩SGA新生儿的比值比为2.22（95%CI，1.28 - 3.85）。限于接受宫缩抑制剂治疗患者的亚组分析显示了类似结果。
子宫收缩增强发作消退且足月分娩的患者有分娩SGA新生儿的风险，这表明假性早产发作并非良性情况。我们提出，对胎儿-胎盘单位的损伤可能通过不可逆的早产分娩或胎儿生长受限来解决。
