Induction of labour for suspected fetal macrosomia

 

Abstract

Background

Women with a suspected macrosomic fetus are at risk of difficult operative delivery or caesarean section. Neonatal trauma may complicate the delivery. Induction of labour may reduce these risks by limiting the fetal growth and, therefore, decrease the birthweight. However, this intervention per se may be associated with an increased risk of caesarean section.

Objectives

To assess the effects of a policy of labour induction for suspected fetal macrosomia on method of delivery and maternal or perinatal morbidity.

Search methods

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (January 2011).

Selection criteria

Randomised trials of induction of labour for suspected fetal macrosomia in non-diabetic women.

Data collection and analysis

Both review authors independently assessed trial quality and extracted the data. We contacted study authors for additional information.

Main results

We included three trials, involving 372 women. Compared to expectant management, induction of labour for suspected macrosomia has not been shown to reduce the risk of caesarean section (relative risk (RR) 0.96, 95% confidence interval (CI) 0.67 to 1.38) or instrumental delivery (RR 1.02, 95% CI 0.60 to 1.74). Perinatal morbidity was not statistically different between groups (shoulder dystocia: RR 1.06, 95% CI 0.44 to 2.56); one trial reported, however, two cases of brachial plexus injury and four cases of fracture in the expectant management group.

Authors' conclusions

Induction of labour for suspected fetal macrosomia in non-diabetic women has not been shown to alter the risk of maternal or neonatal morbidity, but the power of the included studies to show a difference in rare events is limited. Larger trials are needed to address this question.

 

Plain language summary

Induction of labour for suspected fetal macrosomia

No evidence of improved outcomes following induction of labour for non-diabetic women who are thought to be carrying large babies.

Babies who are very large (macrosomic - over 4500 g) can sometimes have difficult and, occasionally, traumatic births. One suggestion to try to reduce this trauma and to reduce operative births has been to induce labour before the baby grows too big. However, the estimation of the baby's weight in utero is difficult and not very accurate. Clinical estimations are based on feeling the uterus and measuring the height of the fundus of the uterus, and both are subject to considerable variation. Ultrasound scanning is also not accurate. Induction, if undertaken too early, can lead to babies being born prematurely and with immature organs. The review of trials, assessing induction of women when it was suspected that their baby was above 4 kg, found three trials involving 372 women, none of them with diabetes. There was no evidence of any benefit in terms of caesarean section or instrumental births, or in outcomes for the baby. However, these studies were too small to be sure of the outcomes. Further research is in progress.

 

摘要

背景

疑似胎兒體重過重之引產

疑似胎兒太大(胎兒體重過重)之婦女，器械生產或剖腹產風險增加。新生兒創傷也使生產更複雜。引產而限制胎兒生長、減少生產體重，因此，可以減少這些風險。不過，就此介入方式本身而言，和剖腹產風險增加有關

目標

評估疑似胎兒體重過重之引產策略對生產方法和母親或生產前後發病率的效果

搜尋策略

我們搜尋Cochrane Pregnancy和Childbirth Group's Trials Register (2007年9月)

選擇標準

非糖尿病婦女疑似胎兒體重過重引產之隨機試驗

資料收集與分析

2位回顧作者獨立評估試驗品質和摘錄資料。我們聯絡研究作者以獲得額外資訊

主要結論

納入3篇試驗、372名婦女。相較於期待性管理，疑似胎兒體重過重引產無法降低剖腹產風險(RR為0.96, 95% CI為0.67 – 1.38)或使用器械生產風險(RR為1.02, 95% CI為0.60 – 1.74)。兩組之間的生產前後發病率並無顯著差異(肩難產；RR為1.06, 95% CI為0.44 – 2.56)；不過，有1篇報告指出，在期待性管理組有2例臂神經叢受傷、4例骨折

作者結論

非糖尿病婦女疑似胎兒體重過重引產，並未顯示可改變母親或新生兒發病率風險，但是納入的試驗之研究強度有限而無法顯示出罕見事件的差異。需要更大型的試驗來表述此一問題

翻譯人

此翻譯計畫由臺灣國家衛生研究院(National Health Research Institutes, Taiwan)統籌

總結

疑似胎兒體重過重之引產。 非糖尿病婦女疑似胎兒體重過重之引產並無可改善結果之證據。胎兒太大(胎兒體重過重超過4500克)，有時候會有生產困難，偶爾會造成生產創傷。有人認為在胎兒還沒長太大之前引產，可以減少此創傷和減少手術生產，不過，估計胎兒在子宮內的體重有其困難且不是非常準確。臨床估計是根據子宮的感覺和測量子宮底的高度，兩者都因主觀考量而有差異。超音波掃描也不準確。如果太早引產，會造成胎兒早產且器官未成熟。此次試驗回顧，評估胎兒體重疑似超過4公斤時的引產，有3篇試驗、372名婦女，都不是糖尿病患。就剖腹產或使用器械生產、嬰兒結果等方面之利益都沒有證據，不過，這些研究規模都太小而沒有確定的結果，後續研究進行中