Ampt Amanda J, Patterson Jillian A, Roberts Christine L, Ford Jane B
Clinical and Population Perinatal Health Research, The Kolling Institute, Northern Clinical School, University of Sydney, St Leonards, NSW, Australia.
Clinical and Population Perinatal Health Research, The Kolling Institute, Northern Clinical School, University of Sydney, St Leonards, NSW, Australia.
Int J Gynaecol Obstet. 2015 Dec;131(3):260-4. doi: 10.1016/j.ijgo.2015.06.025. Epub 2015 Aug 29.
To determine whether rates of obstetric anal sphincter injuries (OASIS) are continuing to increase and whether risk of OASIS according to mode of delivery is constant over time.
In a retrospective population-based study, data were obtained for vaginal singleton vertex deliveries at 37-41 weeks of pregnancy among primiparous women in New South Wales, Australia, between January 2001 and December 2011. Annual OASIS rates were determined among non-instrumental, forceps, and vacuum deliveries with and without episiotomy. Multivariable logistic regression was used to determine adjusted odds ratios for each delivery mode category by year. Trends in adjusted odds ratios over time for each delivery category were compared.
OASIS occurred in 955 (4.1%) of 23 081 deliveries in 2001 and 1487 (5.9%) of 25 081 deliveries in 2011. After adjustment for known risk factors, the only delivery categories to show statistically significant increases in OASIS over the study period were non-instrumental deliveries without episiotomy (linear trend P<0.001) and forceps deliveries with episiotomy (linear trend P=0.004).
Overall, OASIS rates have continued to increase. Known risk factors do not fully explain the increase in OASIS rates in non-instrumental deliveries without an episiotomy and in forceps deliveries with an episiotomy.
确定产科肛门括约肌损伤（OASIS）的发生率是否持续上升，以及根据分娩方式划分的OASIS风险是否随时间保持不变。
在一项基于人群的回顾性研究中，获取了2001年1月至2011年12月期间澳大利亚新南威尔士州初产妇妊娠37 - 41周单胎头位阴道分娩的数据。确定了有无会阴切开术的非器械助产、产钳助产和真空吸引助产的年度OASIS发生率。采用多变量逻辑回归确定每年每种分娩方式类别的调整比值比。比较了各分娩类别调整比值比随时间的变化趋势。
2001年23081例分娩中有955例（4.1%）发生OASIS，2011年25081例分娩中有1487例（5.9%）发生OASIS。在对已知风险因素进行调整后，研究期间OASIS发生率有统计学显著增加的唯一分娩类别是非器械助产且无会阴切开术（线性趋势P<0.001）和产钳助产且有会阴切开术（线性趋势P = 0.004）。
总体而言，OASIS发生率持续上升。已知风险因素不能完全解释非器械助产且无会阴切开术以及产钳助产且有会阴切开术的OASIS发生率增加的情况。
