Uterine muscle relaxant drugs for threatened miscarriage.
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.


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


METHODS
We searched the Cochrane Pregnancy and Childbirth Group Trials Register (4 May 2004), and the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 2, 2004).


METHODS
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.


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


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).


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.
Lede
R
R
Obstetrics and Gynecology, University of Buenos Aires, Argentinian Institute for Evidence Based Medicine, Av. Roque Saenz Peña 825, Buenos Aires, Argentina, 1035. rlede@anmat.gov.ar
Duley
L
L
D000033:Abortion, Threatened / Q000517:prevention & control*; D005260:Female; D006801:Humans; D010276:Parasympatholytics / Q000627:therapeutic use*; D011247:Pregnancy; D015149:Tocolytic Agents / Q000627:therapeutic use*
D010276:Parasympatholytics; D015149:Tocolytic Agents