研究:在足月前選擇提早生產是可以的


  【24drs.com】根據一篇超過600,000名嬰兒的人口基礎回溯世代研究,相較於預期在妊娠39週以上生產者,選擇在妊娠37-38週提早生產的嬰兒,新生兒發病率或嬰兒死亡率風險並不會增加,不過,研究者發現,某些選擇性剖腹產的嬰兒的不良結果比率上升。
  
  德州休士頓貝勒醫學院家庭與社區醫學部Jason L. Salemi博士等人在3月9日的婦產科(Obstetrics & Gynecology)期刊線上發表他們的研究結果。
  
  研究結果與美國婦產科協會和母嬰醫學會目前的建議背道而馳,聯合委員會的意見指明,雖然妊娠39週前生產有特定的適應症,非醫學適應症的提早生產是不適當的。
  
  研究者寫道,相對於當前的教條,我們發現,當使用適當研究方法選定對照組時,妊娠39週前提早生產與不良結果的可能性增加無關。
  
  Salemi博士等人主張,以前的研究使用的對照組不恰當。藉由比較選擇性提早生產和晚期自發性分娩,研究可能會高估選擇性提早生產的不良影響。因為臨床決定必須是在選擇性提早生產和預產期生產之間作選擇,之後的分娩成果仍是未知,適當的對照組應包括所有適合選擇性提早生產,但是在足月後才生產的嬰兒。
  
  研究者將這些嬰兒分類為:在預產期後、妊娠39-40週生產的對照組;或者以下四個提早生產(妊娠37 – 38週)組:選擇性誘導分娩、選擇性剖腹產但無分娩試驗、自然產、醫囑分娩。
  
  大多數嬰兒(64.6%)是足月產,早產的嬰兒中,50%是在產程啟動之後自然產出(n = 112,846),40%是在選擇性誘導之後(n = 33,213)或剖腹產(n = 55,515)。
  
  整體而言,51,846名(8.2%)嬰兒發生不良結果,其中最常見的是呼吸道發病率(5.98%;95%信賴區間[CI], 5.92% - 6.04%)。新生兒加護病房(NICU)住院率為2.61% (95% CI, 2.57% - 2.65%)。嬰兒死亡率為1.46/1000名活產(95% CI, 1.37 - 1.56),共有928名嬰兒死亡。新生兒敗血症(1.34%;95% CI, 1.31% - 1.37%)和餵養困難(1.26%;95% CI, 1.23% - 1.29%)的發生率幾乎相同。
  
  研究者寫道,縱觀所有發病率,提早誘導組的比率和足月組相似。反之,提早剖腹產組每項結果的發生率都高於足月組,而呼吸道發病率和NICU住院率方面,則是提早誘導組的近2倍。
  
  校正潛在的干擾因素之後,相較於足月嬰兒,提早誘導組的嬰兒在呼吸道發病率、新生兒敗血症、NICU住院率方面之風險並未增加,但是他們的餵養困難風險增加(勝算比[OR], 1.18;99% CI, 1.02 - 1.36)。
  
  不過,提早剖腹產組嬰兒的所有發病率結果的機率都增加;相對於足月組,新生兒敗血症的風險僅增加13% (OR, 1.13;99% CI, 1.01 - 1.27),但是,呼吸道發病率增加66%、NICU住院率增加51%、餵養困難比率增加36%。
  
  研究者寫道,雖然我們提早誘導的多項不良結果發生率並無差異,這項研究結果與許多已發表的文獻矛盾,我們的研究結果與使用適當研究方法指定對照組的少數研究是一致的。
  
  研究者結論指出,何時啟動產程的時機和原因的相關議題是複雜的,因為每次懷孕都是獨特的。一般雖建議避免選擇性提早分娩,這篇研究新增了小而具體的文獻證據,在這新領域中,根據更好的資料強化支持、繼續研究。
  
  資料來源: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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