By John C. Hobbins, MD, Professor, Department of Obstetrics and Gynecology, University of Colorado School of Medicine, Aurora. Dr. Hobbins reports no financial relationships relevant to this field of study.
Synopsis: A recent multicenter study has shown that restricted activity not only does not decrease the rate of preterm birth in nulliparous patients with cervical length < 3 cm, but it can actually double this risk.
Source:Grobman WA, et al. Activity restriction among women with a short cervix. Obstet Gynecol 2013;121:1181-1186.
Financial Disclosure: OB/GYN Clinical Alert's editor, Jeffrey T. Jensen, MD, MPH, is a consultant for Bayer Healthcare and Population Council; is a speaker for Bayer Healthcare and Merck; receives research support from Agile Pharmaceuticals, Bayer Healthcare, HRA Pharma, Merck, and Population Council; and is on the advisory boards of Bayer Healthcare, Merck, HRA Pharma, and Agile Pharmaceuticals. Peer reviewer Catherine Leclair, MD; executive editor Leslie Coplin, and managing editor Neill Kimball report no financial relationships relevant to this field of study.
Bed rest is still frequently prescribed to prevent or treat various conditions in pregnancy. Yet, since it is intrusive and costly, the practice is periodically challenged. A recent paper provides some compelling data on the effect of "restricted activity" to prevent preterm birth in nulliparas with short cervices.1
Authors from the NICHD Maternal-Fetal Medicine Units Network recently published a study evaluating the efficacy of 17 alpha-OH progesterone caproate (17P) in preventing preterm birth in nulliparas with short cervices (< 3 cm) found with ultrasound in the second trimester.2 In this study, data were available for secondary analysis on 646 of these patients regarding to what extent, if any, activity was restricted. These patients were classified according to whether they were put on "pelvic rest" (no intercourse) or work- or non-work-related restrictions. The decision to restrict activity was at the discretion of the managing providers. The primary outcomes analyzed were birth prior to 34 weeks and prior to 37 weeks.
Interestingly, 252 patients (39%) with short cervices had some form of restriction applied. These women were more apt to be older, to have private insurance, and to be non-white Hispanics. Also, there was a greater tendency for these women to have shorter cervices and funneling. Before applying methods to account for the above confounding variables, the overall rate of preterm birth at < 37 weeks in "the resters" was 37% vs 17% and the "non-resters" (odds ratio [OR], 2.91; 95% confidence interval [CI]; 2.0-4.21). After controlling for age and confounding demographic, social, and cervical findings, there still was a significant difference between groups (OR, 2.37; 95% CI, 1.60-3.53). When using preterm birth < 34 weeks as a dependent variable, again, there were significant differences between the two groups (OR, 2.28; 95% CI, 1.36-3.80).
It is a rare clinician who has not recommended restricted activity for some obstetrical condition like preterm labor or hypertension. In some circumstances, it makes sense to simply "quiet things down." In fact, in a 1994 survey of obstetricians, 98% indicated they had recommended bed rest or decreased activity in some clinical situations,3and in a more recent survey, 71% of maternal-fetal medicine physicians said they recommended it after arrested preterm labor, despite most admitting that there was poor evidence to support this practice.4
An anticipated response might be "but it might help and it doesn't seem to hurt." Well, in fact, this may not be true. This study shows that it may actually hurt — at least if one were trying to prevent preterm birth. And there is ample evidence that bed rest predisposes patients to thromboembolism and bone demineralization, and it can also negatively affect psychological well being. Additionally, bed rest can significantly impact the financial state of the family. In 1994, Goldenberg et al calculated that the annual cost (to U.S. society) of prescribed antepartum bed rest was approximately $1 billion.3In 2013, the inflated cost would likely be more than double that figure.
In a companion article in the same issue of Obstetrics &Gynecology, McCall et al5reviewed pertinent Cochrane database studies that also showed no benefit from bed rest in the treatment of preterm birth,6hypertension,7preeclampsia,8 threatened abortion,9 or multiple gestation.10By applying the non-malfeasance vs beneficence (risk/benefit) analysis favored by bioethicists, the authors concluded that it was unethical to prescribe bed rest for the prevention or treatment of any of the above conditions. These authors even stated that "if bed rest is to be used, it should be only within a formal clinical trial."
That should get our attention!