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Increased monitoring of women at risk for preterm labour did not decrease the rate of preterm birth
OBS T E TR ICS
Increased monitoring of women at risk for preterm labour did not decrease the rate of preterm birth Dyson DC, Danbe KH, Bamber JA, Crites YM, Field DR, Maier JA, Newman LA, Ray DA, Walton DL, Armstrong MA. Monitoring women at risk for preterm labor. N Engl J Med 1998; 338: 15d19
OBJECTIVE To determine the effect on preterm birth of daily contact with a nurse and/or home monitoring of uterine activity in women at risk for preterm labour. DESIGN Multicentre, randomized, assessor-blind, 3-arm trial. Allocation was by computer-generated randomization list, stratified for number of fetuses and treatment centre. The study had sufficient power to detect an absolute difference of 5% in the rate of preterm birth. SETTING 30 HMO clinics and eight hospitals in the USA. SUBJECTS 2422 pregnant women, who had at least one risk factor for preterm labour, were enrolled at 24–33 weeks gestation. Mean age was 29 years, mean gravidity was 3 and 32% were nulliparous. 91% of women had at least high school education. The most common risk factors were twin gestation (35%), prior preterm birth (19%) or labour (17%), and uterine irritability (11%). INTERVENTION All women assessed frequency of contractions twice daily. 798 women were randomized to receive a weekly telephone call from a nurse and 796 to receive a daily call, and 828 to receive a daily call and use a device to monitor uterine contractions. If symptoms of preterm labour persisted, the woman contacted her obstetrician, who was unaware of her treatment. MAIN OUTCOME MEASURES Preterm birth ((35 weeks), cervical dilatation at start of preterm labour, birth weight.
CONCLUSION Increased surveillance of women at risk of preterm labour, with daily telephone calls from a nurse and/or home monitoring of uterine contractions, did not decrease the rate of preterm birth, but did increase the number of unscheduled clinic visits and the use of drugs.
MAIN RESULTS The proportion of women who delivered at (35 weeks was 14% in the weekly contact group, 13% in the
* Numbers calculated from data in article.
Commentary
1292 women to twice-daily nursing contact and either active or shammonitoring. HUAM did not improve outcomes. The present study, the largest to date, confirmed this finding, as did another recent, small trial.3 Twenty years ago, electronic fetal monitoring in labor took North American obstetrics by storm. By the time randomized, controlled trials were done, ultimately showing no long-term benefit for babies, the technology had been firmly entrenched. In contrast, clinicians today have ample evidence that HUAM does not work and should not be used. HUAM is very expensive. Every dollar spent on HUAM is a dollar that cannot be spent on programs that improve the health of women and their children.
This large, well-designed trial should put the final nail in the coffin of home uterine activity monitoring (HUAM). Based on flawed, early studies and aggressive promotion, this technology made major inroads into North American obstetrical practice. For example, an earlier trial with favorable results, sponsored by a HUAM manufacturer, was analyzed incorrectly, but spawned a series of articles in a journal supplement touting the benefit of HUAM. The trial’s authors had excluded two-thirds of all enrolled participants prior to the analysis. Other investigators later showed that, if all trial participants with follow-up information were analysed by intention-to-treat, the significant benefit of HUAM disappeared. In another widely cited paper that led to approval of a HUAM device by the US Food and Drug Administration, the authors focused on the wrong outcome, cervical dilation, rather than premature birth and its complications. The quality of early trials of HUAM was poor. One attempt to perform a formal meta-analysis of the first five trials concluded that the low trial quality precluded aggregation of the data. However, the overall assessment was that methodological flaws could easily have accounted for the small overall benefit observed. A subsequent meta-analysis of the first six trials, sponsored by industry, concluded that HUAM was helpful in several ways.1 More recently, larger, better designed, randomized, controlled trials have turned the tide. The pivotal study was the multicentre trial sponsored by the US National Institutes of Health.2 This trial randomized
106
daily contact group, and 14% in the home monitoring group ( p"0.77*). There was no difference among groups in the proportions of babies with birth weight (2500 g or (1500 g. The mean ($SD) number of unscheduled clinic visits was 1.2$1.5 in the weekly contact group, 1.8$2.0 in the daily contact group, and 2.3$2.3 in the home monitoring group ( p(0.002, each pairwise comparison). The proportions of women who received prophylactic tocolytic drug therapy were 12, 14, and 19%, respectively ( p(0.01, home monitoring vs other groups). The proportion of women diagnosed with preterm labour at (35 weeks was 23% in the weekly contact group, 22% in the daily contact group, and 27% in the home monitoring group ( p"0.06). Among these women, there was no difference by treatment group in the gestational age at preterm labour or at delivery. The mean cervical dilatation at diagnosis of preterm labour was 1.8$2.0 cm in the weekly contact group, 1.5$ 1.2 cm in the daily contact group, and 1.4$1.2 cm in the home monitoring group (NS). The proportions of women with preterm labour delivering at (35 weeks were 46, 51 and 56%, respectively ( p"0.15*).
Evidence-based Obstetrics and Gynecology (1999) 1, 106
David A. Grimes, MD University of North Carolina, Chapel Hill, NC, USA
Literature cited 1. Colton T, Kayne HL, Zhang Y, Heeren T. A metaanalysis of home uterine activity monitoring. Am J Obstet Gynecol 1995; 173: 1499d1505 2. The Collaborative Home Uterine Monitoring Study (CHUMS) Group. A multicenter randomized controlled trial of home uterine monitoring: active versus sham device. Am J Obstet Gynecol 1995; 173: 1120d1127 3. Brown HL, Britton KA, Brizendine EJ et al. Randomized comparison of home uterine activity monitoring in the outpatient management of women treated for preterm labor. Am J Obstet Gynecol 1999; 180: 798d805
^ 1999 Harcourt Publishers Ltd
Increased monitoring of women at risk for preterm labour did not decrease the rate of preterm birth Dyson DC, Danbe KH, Bamber JA, Crites YM, Field DR, Maier JA, Newman LA, Ray DA, Walton DL, Armstrong MA. Monitoring women at risk for preterm labor. N Engl J Med 1998; 338: 15d19
OBJECTIVE To determine the effect on preterm birth of daily contact with a nurse and/or home monitoring of uterine activity in women at risk for preterm labour. DESIGN Multicentre, randomized, assessor-blind, 3-arm trial. Allocation was by computer-generated randomization list, stratified for number of fetuses and treatment centre. The study had sufficient power to detect an absolute difference of 5% in the rate of preterm birth. SETTING 30 HMO clinics and eight hospitals in the USA. SUBJECTS 2422 pregnant women, who had at least one risk factor for preterm labour, were enrolled at 24–33 weeks gestation. Mean age was 29 years, mean gravidity was 3 and 32% were nulliparous. 91% of women had at least high school education. The most common risk factors were twin gestation (35%), prior preterm birth (19%) or labour (17%), and uterine irritability (11%). INTERVENTION All women assessed frequency of contractions twice daily. 798 women were randomized to receive a weekly telephone call from a nurse and 796 to receive a daily call, and 828 to receive a daily call and use a device to monitor uterine contractions. If symptoms of preterm labour persisted, the woman contacted her obstetrician, who was unaware of her treatment. MAIN OUTCOME MEASURES Preterm birth ((35 weeks), cervical dilatation at start of preterm labour, birth weight.
CONCLUSION Increased surveillance of women at risk of preterm labour, with daily telephone calls from a nurse and/or home monitoring of uterine contractions, did not decrease the rate of preterm birth, but did increase the number of unscheduled clinic visits and the use of drugs.
MAIN RESULTS The proportion of women who delivered at (35 weeks was 14% in the weekly contact group, 13% in the
* Numbers calculated from data in article.
Commentary
1292 women to twice-daily nursing contact and either active or shammonitoring. HUAM did not improve outcomes. The present study, the largest to date, confirmed this finding, as did another recent, small trial.3 Twenty years ago, electronic fetal monitoring in labor took North American obstetrics by storm. By the time randomized, controlled trials were done, ultimately showing no long-term benefit for babies, the technology had been firmly entrenched. In contrast, clinicians today have ample evidence that HUAM does not work and should not be used. HUAM is very expensive. Every dollar spent on HUAM is a dollar that cannot be spent on programs that improve the health of women and their children.
This large, well-designed trial should put the final nail in the coffin of home uterine activity monitoring (HUAM). Based on flawed, early studies and aggressive promotion, this technology made major inroads into North American obstetrical practice. For example, an earlier trial with favorable results, sponsored by a HUAM manufacturer, was analyzed incorrectly, but spawned a series of articles in a journal supplement touting the benefit of HUAM. The trial’s authors had excluded two-thirds of all enrolled participants prior to the analysis. Other investigators later showed that, if all trial participants with follow-up information were analysed by intention-to-treat, the significant benefit of HUAM disappeared. In another widely cited paper that led to approval of a HUAM device by the US Food and Drug Administration, the authors focused on the wrong outcome, cervical dilation, rather than premature birth and its complications. The quality of early trials of HUAM was poor. One attempt to perform a formal meta-analysis of the first five trials concluded that the low trial quality precluded aggregation of the data. However, the overall assessment was that methodological flaws could easily have accounted for the small overall benefit observed. A subsequent meta-analysis of the first six trials, sponsored by industry, concluded that HUAM was helpful in several ways.1 More recently, larger, better designed, randomized, controlled trials have turned the tide. The pivotal study was the multicentre trial sponsored by the US National Institutes of Health.2 This trial randomized
106
daily contact group, and 14% in the home monitoring group ( p"0.77*). There was no difference among groups in the proportions of babies with birth weight (2500 g or (1500 g. The mean ($SD) number of unscheduled clinic visits was 1.2$1.5 in the weekly contact group, 1.8$2.0 in the daily contact group, and 2.3$2.3 in the home monitoring group ( p(0.002, each pairwise comparison). The proportions of women who received prophylactic tocolytic drug therapy were 12, 14, and 19%, respectively ( p(0.01, home monitoring vs other groups). The proportion of women diagnosed with preterm labour at (35 weeks was 23% in the weekly contact group, 22% in the daily contact group, and 27% in the home monitoring group ( p"0.06). Among these women, there was no difference by treatment group in the gestational age at preterm labour or at delivery. The mean cervical dilatation at diagnosis of preterm labour was 1.8$2.0 cm in the weekly contact group, 1.5$ 1.2 cm in the daily contact group, and 1.4$1.2 cm in the home monitoring group (NS). The proportions of women with preterm labour delivering at (35 weeks were 46, 51 and 56%, respectively ( p"0.15*).
Evidence-based Obstetrics and Gynecology (1999) 1, 106
David A. Grimes, MD University of North Carolina, Chapel Hill, NC, USA
Literature cited 1. Colton T, Kayne HL, Zhang Y, Heeren T. A metaanalysis of home uterine activity monitoring. Am J Obstet Gynecol 1995; 173: 1499d1505 2. The Collaborative Home Uterine Monitoring Study (CHUMS) Group. A multicenter randomized controlled trial of home uterine monitoring: active versus sham device. Am J Obstet Gynecol 1995; 173: 1120d1127 3. Brown HL, Britton KA, Brizendine EJ et al. Randomized comparison of home uterine activity monitoring in the outpatient management of women treated for preterm labor. Am J Obstet Gynecol 1999; 180: 798d805
^ 1999 Harcourt Publishers Ltd