Uterine muscle relaxant drugs for threatened miscarriage

 

Abstract

Background

Miscarriage is the spontaneous loss of a pregnancy before the fetus is viable. Uterine muscle relaxant drugs have been used for women at risk of miscarriage in the belief they relax uterine muscle, and hence reduce the risk of miscarriage.

Objectives

To assess the effects for the woman and her baby of uterine muscle relaxant drugs when used for threatened miscarriage.

Search methods

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (10 September 2009).

Selection criteria

Randomised trials were included, and quasi-randomised trials were excluded. The participants were women with a pregnancy of less than 20 weeks' gestation having a threatened miscarriage. The interventions were any uterine muscle relaxing drugs (including tocolytic and antispasmodic agents) compared with either placebo or no drug. Primary outcomes for the review were miscarriage: defined as spontaneous pregnancy loss before fetal viability, baby death (stillbirth or neonatal death) and maternal death.

Data collection and analysis

Both review authors independently assessed studies for eligibility and trial quality, and extracted data.

Main results

One poor quality trial (170 women) was included. This compared a beta-agonist with placebo. There was a lower risk of intrauterine death associated with the use of a beta-agonist (relative risk (RR) 0.25, 95% confidence interval (CI) 0.12 to 0.51). Preterm birth was the only other outcome reported (RR 1.67, 95% CI 0.63 to 4.38).

Authors' conclusions

There is insufficient evidence to support the use of uterine muscle relaxant drugs for women with threatened miscarriage. Any such use should be restricted to the context of randomised trials.

 

Plain language summary

Uterine muscle relaxant drugs for threatened miscarriage

Not enough evidence to say if drugs that relax the muscles of the uterus can prevent threatened miscarriage.

Miscarriage is the loss of a baby in the very early weeks of pregnancy (before 20 weeks), before the baby would be able to survive on its own. This can be a devastating loss to expectant parents. Threatened miscarriage is when there is vaginal bleeding, and sometimes pain, but when the cervix remains closed. The review of studies found just one small trial on uterine relaxant drugs to prevent miscarriage, but the study provided insufficient data to be able to assess its effect adequately. More research is needed.

 

摘要

背景

針對先兆性流產所用的子宮肌肉鬆弛藥物

流產指的是在胎兒可以存活之前，就產生了自發性的懷孕流失現象。針對處於流產風險之中的婦女，可以使用子宮肌肉鬆弛藥物，因為這些藥物可以鬆弛子宮肌肉，因此便可以降低流產的風險。

目標

當針對先兆性流產而使用了子宮肌肉鬆弛藥物時，要評估這些藥物對於該名婦女與她的嬰兒所產生之功效。

搜尋策略

我們搜尋了the Cochrane Pregnancy and Childbirth Group Trials Register(2004年5月4日)，以及the Cochrane Central Register of Controlled Trials(The Cochrane Library，Issue 2，2004年)。

選擇標準

其中包含了隨機試驗，半隨機試驗則被排除在外。參與者都是少於20周孕期的懷胎婦女，而且都已經發生了先兆性流產。跟安慰劑或是不使用藥物比較起來，要評估子宮肌肉鬆弛用的藥物(包括了安胎藥物與抗肌肉痙攣的的藥物)。本篇回顧的主要預後就是流產：定義為在在胎兒具有存活能力前流失、嬰兒死亡(胎死腹中或是新生兒死亡)，以及母體死亡等情況。

資料收集與分析

有2位審稿的作者，獨立地針對合格程度評估了這些研究與試驗的品質，並擷取出資料。

主要結論

其中共包含了1組品質不良的試驗(170名婦女)。這組試驗將某1種乙型促進劑(betaagonist)與安慰劑進行了比較。因為使用了乙型促進劑而造成子宮內死亡的風險是比較低的(相對風險(RR) 0.25, 95% 信賴區間(CI) 0.12 to 0.51)。早產是僅有的其他類之預後報告(RR 1.67, 95% CI 0.63 to 4.38)。

作者結論

針對遇上先兆性流產的婦女而言，並沒有足夠的證據可以支持使用子宮肌肉鬆弛藥物。任何有關於此類的使用狀況，都應該要限制在以隨機試驗的背景為前提之下。

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

鬆弛子宮肌肉的藥物，是否可以預防先兆性流產，並沒有足夠的證據可以說明。在懷孕之非常早的週數時(在20週之前)，也就是在嬰兒有能力存活下來之前，若是發生了失去嬰兒的情形，這樣就是流產。對於懷著滿心期盼的父母來說，這樣的狀況可能會是痛徹心扉的損失。當陰道發生了流血的現象時，有時候還會有疼痛感，不過此時的子宮頸卻還是維持關閉的，就是先兆性流產。本篇研究的回顧發現，就只有1組小型的試驗，是針對於使用子宮鬆弛藥物來預防流產，但是在這份研究中提供的資料並不充分，以致於無法適當地評估它的功效。還需要有更多的研究。