研究:在足月前选择提早生产是可以的


  【24drs.com】根据一篇超过600,000名婴儿的人口基础回溯世代研究,相较于预期在妊娠39周以上生产者,选择在妊娠37-38周提早生产的婴儿,新生儿发病率或婴儿死亡率风险并不会增加,不过,研究者发现,某些选择性剖腹产的婴儿的不良结果比率上升。
  
  德州休士顿贝勒医学院家庭与社区医学部Jason L. Salemi博士等人在3月9日的妇产科(Obstetrics & Gynecology)期刊在线发表他们的研究结果。
  
  研究结果与美国妇产科协会和母婴医学会目前的建议背道而驰,联合委员会的意见指明,虽然妊娠39周前生产有特定的适应症,非医学适应症的提早生产是不适当的。
  
  研究者写道,相对于当前的教条,我们发现,当使用适当研究方法选定对照组时,妊娠39周前提早生产与不良结果的可能性增加无关。
  
  Salemi博士等人主张,以前的研究使用的对照组不恰当。藉由比较选择性提早生产和晚期自发性分娩,研究可能会高估选择性提早生产的不良影响。因为临床决定必须是在选择性提早生产和预产期生产之间作选择,之后的分娩成果仍是未知,适当的对照组应包括所有适合选择性提早生产,但是在足月后才生产的婴儿。
  
  研究者将这些婴儿分类为:在预产期后、妊娠39-40周生产的对照组;或者以下四个提早生产(妊娠37 – 38周)组:选择性诱导分娩、选择性剖腹产但无分娩试验、自然产、医嘱分娩。
  
  大多数婴儿(64.6%)是足月产,早产的婴儿中,50%是在产程启动之后自然产出(n = 112,846),40%是在选择性诱导之后(n = 33,213)或剖腹产(n = 55,515)。
  
  整体而言,51,846名(8.2%)婴儿发生不良结果,其中最常见的是呼吸道发病率(5.98%;95%信赖区间[CI], 5.92% - 6.04%)。新生儿加护病房(NICU)住院率为2.61% (95% CI, 2.57% - 2.65%)。婴儿死亡率为1.46/1000名活产(95% CI, 1.37 - 1.56),共有928名婴儿死亡。新生儿败血症(1.34%;95% CI, 1.31% - 1.37%)和喂养困难(1.26%;95% CI, 1.23% - 1.29%)的发生率几乎相同。
  
  研究者写道,纵观所有发病率,提早诱导组的比率和足月组相似。反之,提早剖腹产组每项结果的发生率都高于足月组,而呼吸道发病率和NICU住院率方面,则是提早诱导组的近2倍。
  
  校正潜在的干扰因素之后,相较于足月婴儿,提早诱导组的婴儿在呼吸道发病率、新生儿败血症、NICU住院率方面之风险并未增加,但是他们的喂养困难风险增加(胜算比[OR], 1.18;99% CI, 1.02 - 1.36)。
  
  不过,提早剖腹产组婴儿的所有发病率结果的机率都增加;相对于足月组,新生儿败血症的风险仅增加13% (OR, 1.13;99% CI, 1.01 - 1.27),但是,呼吸道发病率增加66%、NICU住院率增加51%、喂养困难比率增加36%。
  
  研究者写道,虽然我们提早诱导的多项不良结果发生率并无差异,这项研究结果与许多已发表的文献矛盾,我们的研究结果与使用适当研究方法指定对照组的少数研究是一致的。
  
  研究者结论指出,何时启动产程的时机和原因的相关议题是复杂的,因为每次怀孕都是独特的。一般虽建议避免选择性提早分娩,这篇研究新增了小而具体的文献证据,在这新领域中,根据更好的资料强化支持、继续研究。
  
  资料来源:http://www.24drs.com/
  
  Native link:Early-Term Elective Delivery May Be OK, Study Suggests

Early-Term Elective Delivery May Be OK, Study Suggests

By Troy Brown, RN
Medscape Medical News

Infants born electively at 37 to 38 weeks' gestation are not at increased risk for neonatal morbidity or infant mortality compared with infants who are expectantly managed and born at 39 weeks' gestation or older, according to a population-based retrospective cohort study of more than 600,000 infants. However, the researchers did see elevated rates for adverse outcomes among the subset of infants delivered by elective cesarean.

Jason L. Salemi, PhD, MPH, from the Department of Family and Community Medicine, Baylor College of Medicine, Houston, Texas, and colleagues report their findings in an article published online March 9 in Obstetrics & Gynecology.

The study findings run counter to current recommendations from the American College of Obstetricians and Gynecologists and the Society for Maternal-Fetal Medicine. A joint committee opinion specifies, "Although there are specific indications for delivery before 39 weeks of gestation, a nonmedically indicated early-term delivery is not appropriate."

"In contrast to the current dogma, we found that when a methodologically appropriate comparison group was used, elective induction before 39 weeks of gestation was not associated with an increased likelihood of adverse outcomes," the researchers write.

Dr Salemi and colleagues contend that previous studies have used inappropriate comparison groups. "By comparing elective early-term deliveries with later term spontaneous deliveries alone, studies may be overestimating adverse effects of elective early-term delivery. Because the clinical decision that must be made is a choice between elective early-term delivery and expectant management, in which the later delivery outcome remains unknown, the appropriate comparison group should consist of all infants who were candidates for elective early-term delivery but whose deliveries occurred at a later gestational age."

The researchers classified the infants into either a control group born at 39 to 40 weeks of gestation after expectant management or one of four early-term (37 - 38 weeks' gestation) delivery groups: infants who were born by electively induced delivery, elective cesarean delivery without a trial of labor, spontaneous delivery, and medically indicated delivery.

Most of the infants (64.6%) were born full-term. Among the babies born early-term, 50% were born after spontaneous onset of labor (n = 112,846) and 40% were delivered after elective induction (n = 33,213) or cesarean birth (n = 55,515).

Overall, 51,846 (8.2%) infants experienced an adverse outcome, the most prevalent of which was respiratory morbidity (5.98%; 95% confidence interval [CI], 5.92% - 6.04%). The neonatal intensive care unit (NICU) admission rate was 2.61% (95% CI, 2.57% - 2.65%). The infant mortality rate was 1.46 per 1000 live births (95% CI, 1.37 - 1.56), with 928 infant deaths. Neonatal sepsis (1.34%; 95% CI, 1.31% - 1.37%) and feeding difficulties (1.26%; 95% CI, 1.23% - 1.29%) occurred at approximately the same rate.

"Across all morbidities, the early induced group had rates that were similar to the full-term group. Conversely, the early cesarean delivery group experienced higher rates of each outcome than the full-term group and, for respiratory morbidities and NICU admissions, approximately doubled the rate of the early induced group," the researchers write.

After adjustment for potential confounders, babies born after early induction did not have an increased risk for respiratory morbidity, neonatal sepsis, or NICU admission compared with the full-term babies, but they did have an increased risk for feeding difficulty (odds ratio [OR], 1.18; 99% CI, 1.02 - 1.36).

Odds for all morbidity outcomes were higher among infants in the early cesarean delivery group, however. The increase in risk for neonatal sepsis relative to the full-term group was only 13% (OR, 1.13; 99% CI, 1.01 - 1.27) but it was 66% higher for respiratory morbidity, 51% higher for NICU admission, and 36% higher for feeding difficulties.

"Although our findings of no difference in the odds of several adverse outcomes among early inductions contradict much of the published literature, our results are in general agreement with the few studies that have used a methodologically appropriate comparison group," the researchers write.

"The issues that surround the timing and reasons for delivery initiation are complicated and each pregnancy unique," the authors conclude. "This study adds to a small but growing body of literature that cautions against a general avoidance of all elective early-term deliveries and fosters support for continued research, based on better data, in this still relatively new arena."

The study was supported by a grant from the Agency for Healthcare Research and Quality. The authors have disclosed no relevant financial relationships.

Obstet Gynecol. 2016;127:657-666.

    



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