A metaanalysis of home uterine activity monitoring

Abstract

OBJECTIVE: Our purpose was to assess by metaanalysis the evidence from randomized clinical trials regarding home uterine activity monitoring. STUDY DESIGN: Six randomized controlled trials of home uterine activity monitoring, the same six trials reviewed by the U.S. Preventive Services Task Force on home uterine activity monitoring, were studied. Data were extracted from published reports of the six trials. In addiiton, unpublished data were obtained by personal communication from the trials' principal investigators. Insofar as possible, the principle of intention-to-treat was maintained. Data regarding twins were handled by use of numbers of pregnancies rather than numbers of infants as sample sizes. Stratified metanalysis were conducted according to whether the trial did or did not control in study design for the nursing contact factor that accompanies home uterine activity monitoring. In addition, stratified metaanalysis were conducted for singleton and twin pregnancies. The four outcomes investigated were incidence of preterm birth, incidence of preterm labor combined with cervical dilatation >2 cm, infant referral to the intensive care unit, and mean birth weight. RESULTS: Overall, for all pregnancies home uterine activity monitoring was associated with a statistically significant reduction of 52% in risk of preterm labor combined with cervical dilatation >2 cm (relative risk = 0.48, p = 0.001) and a statistically significant increase of 86 gm in mean birth weight ( p = 0.038). When stratified by singleton or twin pregnancy, the pooled results generally differed by strata. Among singleton pregnancies, home uterine activity monitoring was associated with a statistically significant reduction of 24% in risk of preterm birth (relative risk 0.76, p = 0.037) and a statistically significant increase of 126 gm in mean birth weight ( p = 0.009). Among twin pregnancies, there was a statistically significant effect of home uterine activity monitoring with a reduction of 56% in risk of preterm labor combined with cervical dilatation >2 cm (relative risk 0.44, p = 0.005). There were no statistically significant effects found overall and in any stratum with regard to infant referral to the intensive care unit. Metaanalysis of studies that controlled in design for the nursing contact factor that accompanies home uterine activity monitoring showed either no difference or stronger pooled effects compared with metaanalyses of those studies that did not control for nursing contact. This suggest that the potential bias attributed to the nursing contact feature that accompanies home uterine activity monitoring is not as appreciable as home uterine activity monitoring critics have suggested. CONCLUSIONS: Metaanalysis of existing clinical trial evidence regarding home uterine activity monitoring reveals statistically significant benefits of home uterine activity monitoring. Of the outcomes investigated, home uterine activity monitoring is associated with reductions in risks of preterm birth (in singleton pregnancies only) and preterm labor combined with cervical dilatation >2 cm, as well as with increased mean birth weight (in singleton pregnancies only).