Induction of labour for improving birth outcomes for women at or beyond term

Abstract

As a pregnancy continues beyond term the risks of babies dying inside the womb or in the immediate newborn period increase. Whether a policy of labour induction at a predetermined gestational age can reduce this increased risk is the subject of this review. To evaluate the benefits and harms of a policy of labour induction at term or post-term compared to awaiting spontaneous labour or later induction of labour. We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (June 2006). We updated this search on 14 July 2009 and added the results to the awaiting classification section. Randomized controlled trials conducted in women at or beyond term. The eligible trials were those comparing a policy of labour induction to a policy of awaiting spontaneous onset of labour. Trials comparing cervical ripening methods, membrane stripping/sweeping or nipple stimulation without any commitment to delivery within a certain time were excluded. Two review authors independently evaluated potentially eligible trials and extracted data. Outcomes are analysed in two main categories: gestational age and cervix status. We included 19 trials reporting on 7984 women. A policy of labour induction at 41 completed weeks or beyond was associated with fewer (all-cause) perinatal deaths (1/2986 versus 9/2953; relative risk (RR) 0.30; 95% confidence interval (CI) 0.09 to 0.99). The risk difference is 0.00 (95% CI 0.01 to 0.00). If deaths due to congenital abnormality are excluded, no deaths remain in the labour induction group and seven deaths remain in the no-induction group. There was no evidence of a statistically significant difference in the risk of caesarean section (RR 0.92; 95% CI 0.76 to 1.12; RR 0.97; 95% CI 0.72 to 1.31) for women induced at 41 and 42 completed weeks respectively. Women induced at 37 to 40 completed weeks were less likely to have a caesarean section than those in the expectant management group (RR 0.58; 95% CI 0.34 to 0.99). There were fewer babies with meconium aspiration syndrome (41+: RR 0.29; 95% CI 0.12 to 0.68, four trials, 1325 women; 42+: RR 0.66; 95% CI 0.24 to 1.81, two trials, 388 women). A policy of labour induction after 41 completed weeks or later compared to awaiting spontaneous labour either indefinitely or at least one week is associated with fewer perinatal deaths. However, the absolute risk is extremely small. Women should be appropriately counselled on both the relative and absolute risks. [Note: The 10 citations in the awaiting classification section of the review may alter the conclusions of the review once assessed.] 足月或超過預產期之孕婦引產以改善生產結果 足月之後仍未生產，胎兒死於子宮內或出生後不久死亡的風險增加。比回顧之目標為評估在特定懷孕周數引產是否會減少這種增加的風險。 評估足月和超過預產期時的引產策略和等待自然生產或稍後引產之利益與風險的比較。 我們搜尋Cochrane Pregnancy和Childbirth Group's Trials Register (2006年6月)。 對足月或超過預產期之婦女進行的隨機控制試驗(Randomized controlled trials)。適合的是比較引產策略和等待自然開始產程的試驗。比較子宮頸成熟方法、羊膜剝離或刺激乳頭，但未承諾在一特定時間內生產的試驗被排除。 2位回顧作者獨立評估可能適用的試驗和摘錄資料。主要分為2類結果進行分析：妊娠年紀和子宮頸狀態。 納入19篇試驗、7984名婦女。妊娠滿41週之後的引產策略與各種原因之生產前後死亡減少有關(1/2986相較於9/2953;RR為0.30; 95% CI為0.09 – 0.99)，風險差異為0.00(95% CI為0.01 – 0.00)。排除因為妊娠異常而死亡者之後，引產組沒有死亡事件，非引產組有7件死亡。剖腹產風險方面也沒有顯著差異，妊娠滿41和42週的引產分別是(R .92; 95% CI 0.76 −1.12)、(RR為0.97; 95% CI為0.72 – 1.31)。相較於引產組，37 – 40週非引產的婦女比較可能執行剖腹產(RR為0.58; 95% CI為0.34 – 0.99)。較少嬰兒有胎便吸入症候群(滿41週: RR為0.29 5% CI為0.12 – 0.68,4篇試驗、1325名婦女；滿42週 R為0.66; 95% CI為0.24 – 1.81, 2篇試驗、388名婦女)。 相較於無限期地等或至少等1週的等待自然生產，妊娠滿41週之後的引產政策與較少生產前後死亡有關，不過，絕對風險相當小。應和婦女適當諮商相對和絕對風險。 此翻譯計畫由臺灣國家衛生研究院(National Health Research Institutes, Taiwan)統籌。 超過預產期之孕婦引產以改善生產結果。 正常懷孕或超過預產期之引產。正常懷孕是從婦女最後月經期開始之後40週，但是在37 – 42週都可以視為正常範圍。37週前生產被視為早產，因為這些嬰兒一般會有呼吸困難和其他問題，有些器官如肝臟還未完全成熟。42週之後生產似乎會使嬰兒的風險略為增加，此次回顧試圖釐清在一事先設定的時間引產是否能降低此一增加的風險。目前沒有試驗可以證明讓胎兒留在子宮內比較好、或者是引產比較好，因此無法提出確定的時間限制。此次回顧19篇試驗、約8000名婦女，從妊娠38週超過42週的不同時間進行引產；有些是相當舊的試驗且試驗品質各異。此次回顧根據引產時間將這些試驗分成以下幾組：(1) 37 – 40週；(2)妊娠滿41週；以及(3)妊娠滿42週，和等到更之後的日期者比較。妊娠滿41週之後的引產策略與較少嬰兒死亡有關，不過，不論是哪個時間點，這類死亡都罕見。有關婦女對這些選擇的經驗和意見未被適當評估。 Inducción del trabajo de parto para mejorar los resultados en mujeres a término o después del término Cuando un embarazo continúa después del término, aumenta el riesgo de que el recién nacido muera en el útero o durante el período neonatal inmediato. El tema de esta...