Elective Induction of Labor and Pregnancy Outcomes

描述（研究者提供）：背景和目标：在美国，每年有多达49万名孕妇接受选择性引产，这是一种没有医学原因的引产干预。这是否会对妇女或胎儿造成风险尚不清楚。最近只有一项临床试验研究了妊娠41周前的选择性引产，结果发现，与继续妊娠（待产管理）相比，结果没有差异。观察性研究发现，更多的剖宫产是在引产后发生的，但大多数研究都将引产与同胎龄的自然分娩进行了比较，这并不是真正的临床选择。相反，应该将选择性诱导与真正的替代方案——预期管理进行比较。大多数研究规模太小，无法研究不常见但重要的结果，也没有研究母亲的种族/民族或肥胖是否会导致风险不同。我们的目标是比较妊娠38、39或40周择期引产与准产管理的结果，以帮助孕妇及其提供者做出更明智的决定。方法：对2001 ~ 2011年两个综合卫生保健系统的新生儿进行多阶段回顾性研究。在第一阶段，符合条件的人口（20.6万名独生子女）将

DESCRIPTION (provided by investigator): Background and goals: Each year in the US, up to 490,000 pregnant women undergo elective induction, an intervention to bring on labor without a medical reason. Whether this causes risks to the woman or fetus is unclear. Only one recent clinical trial studied elective induction before 41 weeks of fetal gestation, and it found no difference in outcomes compared to letting the pregnancy continue (expectant management). Observational studies have found more cesarean delivery after induction, but most compared induction to spontaneous labor at the same gestational age, which is not the genuine clinical alternative. Instead, elective induction should be compared to the true alternative, expectant management. Most studies were too small to study uncommon but important outcomes, and none looked at whether risks differ by the mother's race/ethnicity or obesity. Our goal is to compare outcomes for elective induction at 38, 39 or 40 weeks' gestation versus expectant management, to help pregnant women and their providers make more informed decisions. Methods: A multiphase retrospective study of births from 2001 to 2011 will be conducted in two integrated health care systems. In Phase 1, the eligible population (206,000 singleton births) will be identified and classified by their apparent induction and outcome status based on electronic health plan and birth certificate data. In Phase 2, we will conduct 8000 brief medical record reviews to determine true exposure status (elective induction vs. expectant management). In Phase 3, we will review 3500 records in depth for true outcome status and risk factors. Phases 2 and 3 will oversample women with elective induction or rare outcomes, improving our power to address these specific aims: Aim 1: Compare the risk of the following outcomes after elective induction at 38, 39 or 40 weeks' gestation versus expectant management: cesarean delivery, postpartum hemorrhage, chorioamnionitis, neonatal intensive care unit stay, shoulder dystocia, low Apgar score, stillbirth, and neonatal death; and Aim 2: Examine how risks vary by the mother's race/ethnicity, parity, and pre-pregnancy obesity. Secondary analyses will develop an algorithm to more accurately identify elective inductions from electronic data. Impact: This research will compare elective labor induction at 38, 39 or 40 weeks' gestation to expectant management to provide new information about its risks or benefits for the mother and fetus. Our results could immediately affect clinical practice by helping women and providers make more informed choices together. They will also provide a solid foundation for practice guidelines and policy making.