Leeman Lawrence, Leeman Rebecca
Department of Family and Community Medicine, University of New Mexico School of Medicine, Albuquerque, NM 87131, USA.
Ann Fam Med. 2003 May-Jun;1(1):36-43. doi: 10.1370/afm.8.
Cesarean delivery rates vary widely across populations. Studying communities with low rates of cesarean delivery may identify practices that can lower the cesarean rate.
A population-based historical cohort study included all pregnant women (N = 1132) from 1992 through 1996 in a predominantly Native American region of northwestern New Mexico known to have a high prevalence of gestational diabetes and preeclampsia. The outcomes studied included delivery type (eg, cesarean, operative vaginal, spontaneous vaginal), indication for cesarean delivery, presence of obstetrical risk factors, and use of labor induction or augmentation.
The cesarean delivery rate of the study group (7.3%) was only 35% of the 1996 US rate of 20.7%. Among study participants, the relative risk of a primary cesarean delivery for dystocia was 0.22 (95% CI, 0.14, 0.35). Trial of labor after cesarean delivery was attempted by 93% of study participants compared with 42% of women nationwide in 1994. The cesarean delivery rates for women with diabetes in pregnancy (11.5% versus 35.4%) and preeclampsia (14.8% versus 37.4%) were significantly lower than nationwide rates. Case-mix analysis comparison with a standardized population and comparison of standard (ie, term, singleton, vertex) primiparous women demonstrate that the low rate of cesarean delivery was not because of a lower prevalence of risk factors.
The community's low rate of cesarean delivery is primarily the result of a decreased use of cesarean delivery for labor dystocia and an almost universal acceptance of trial of labor after cesarean delivery. Cultural attitudes toward childbirth, design of the perinatal system, and genetic factors also may explain the low rate of cesarean delivery.
剖宫产率在不同人群中差异很大。研究剖宫产率低的社区可能会找出能够降低剖宫产率的做法。
一项基于人群的历史性队列研究纳入了1992年至1996年在新墨西哥州西北部一个以美洲原住民为主的地区的所有孕妇（N = 1132），该地区已知妊娠期糖尿病和先兆子痫的患病率很高。研究的结局包括分娩方式（如剖宫产、阴道助产、自然阴道分娩）、剖宫产指征、产科危险因素的存在情况以及引产或催产的使用情况。
研究组的剖宫产率（7.3%）仅为1996年美国剖宫产率20.7%的35%。在研究参与者中，因难产进行首次剖宫产的相对风险为0.22（95%CI，0.14，0.35）。1994年，93%的研究参与者尝试了剖宫产术后阴道试产，而全国范围内这一比例为42%。妊娠期糖尿病孕妇（11.5%对35.4%）和先兆子痫孕妇（14.8%对37.4%）的剖宫产率显著低于全国水平。与标准化人群进行病例组合分析比较以及对标准（即足月、单胎、头位）初产妇进行比较表明剖宫产率低并非因为危险因素的患病率较低。
该社区剖宫产率低主要是由于因产程难产而进行剖宫产的情况减少以及剖宫产术后阴道试产几乎被普遍接受。对分娩的文化态度、围产期系统的设计以及遗传因素也可能解释了剖宫产率低的原因。
