Department of Obstetrics and Gynecology, Lucille Packard Children's Hospital, Stanford University School of Medicine, Stanford, and the Department of Obstetrics and Gynecology, Santa Clara Valley Medical Center, San Jose, California.
Obstet Gynecol. 2013 Oct;122(4):845-850. doi: 10.1097/AOG.0b013e3182a39731.
To examine the likelihood of classical hysterotomy across preterm gestational ages and to identify factors that increase its occurrence.
This is a secondary analysis of a prospective observational cohort collected by the Maternal-Fetal Medicine Network of all women with singleton gestations who underwent a cesarean delivery with a known hysterotomy. Comparisons were made based on gestational age. Factors thought to influence hysterotomy type were studied, including maternal age, body mass index, parity, birth weight, small for gestational age (SGA) status, fetal presentation, labor preceding delivery, and emergent delivery.
Approximately 36,000 women were eligible for analysis, of whom 34,454 (95.7%) underwent low transverse hysterotomy and 1,562 (4.3%) underwent classical hysterotomy. The median gestational age of women undergoing a classical hysterotomy was 32 weeks and the incidence peaked between 24 0/7 weeks and 25 6/7 weeks (53.2%), declining with each additional week of gestation thereafter (P for trend <.001). In multivariable regression, the likelihood of classical hysterotomy was increased with SGA (n=258; odds ratio [OR] 2.71; confidence interval [CI] 1.78-4.13), birth weight 1,000 g or less (n=467; OR 1.51; CI 1.03-2.24), and noncephalic presentation (n=783; OR 2.03; CI 1.52-2.72). The likelihood of classical hysterotomy was decreased between 23 0/7 and 27 6/7 weeks of gestation and after 32 weeks of gestation when labor preceded delivery, and increased between 28 0/7 and 31 6/7 weeks of gestation and after 32 weeks of gestation by multiparity and previous cesarean delivery. Emergent delivery did not predict classical hysterotomy.
Fifty percent of women at 23-26 weeks of gestation who undergo cesarean delivery have a classical hysterotomy, and the risk declines steadily thereafter. This likelihood is increased by fetal factors, especially SGA and noncephalic presentation.
: II.
研究经典剖宫产术在不同早产孕周的发生概率，并确定增加其发生的因素。
这是对 Maternal-Fetal Medicine Network 收集的所有接受已知剖宫产术的单胎妊娠妇女前瞻性观察队列的二次分析。根据孕周进行比较。研究了可能影响剖宫产术类型的因素，包括产妇年龄、体重指数、产次、出生体重、小于胎龄儿（SGA）状态、胎儿体位、分娩前的劳动和紧急分娩。
约有 36000 名妇女符合分析条件，其中 34454 名（95.7%）行低位横行剖宫产术，1562 名（4.3%）行经典剖宫产术。行经典剖宫产术的妇女的中位孕周为 32 周，发生率在 24 0/7 周至 25 6/7 周之间达到峰值（53.2%），此后每增加一周妊娠发生率下降（趋势 P<.001）。在多变量回归中，SGA（n=258；比值比[OR] 2.71；置信区间[CI] 1.78-4.13）、出生体重 1000 g 或以下（n=467；OR 1.51；CI 1.03-2.24）和非头位（n=783；OR 2.03；CI 1.52-2.72）的妇女发生经典剖宫产术的可能性增加。在 23 0/7 至 27 6/7 周的孕周之间，以及在分娩前进行劳动时，在 32 周以后，行经典剖宫产术的可能性降低，而在 28 0/7 至 31 6/7 周的孕周之间，以及在 32 周以后，多胎和既往剖宫产术使行经典剖宫产术的可能性增加。紧急分娩并不能预测经典剖宫产术。
50%在 23-26 周接受剖宫产术的妇女行经典剖宫产术，此后风险稳步下降。这种可能性因胎儿因素而增加，特别是 SGA 和非头位。
II。
