RESUMEN
BACKGROUND: We undertook a multicentre randomised controlled trial that compared the standard model of antenatal care with a new model that emphasises actions known to be effective in improving maternal or neonatal outcomes and has fewer clinic visits. METHODS: Clinics in Argentina, Cuba, Saudi Arabia, and Thailand were randomly allocated to provide either the new model (27 clinics) or the standard model currently in use (26 clinics). All women presenting for antenatal care at these clinics over an average of 18 months were enrolled. Women enrolled in clinics offering the new model were classified on the basis of history of obstetric and clinical conditions. Those who did not require further specific assessment or treatment were offered the basic component of the new model, and those deemed at higher risk received the usual care for their conditions; however, all were included in the new-model group for the analyses, which were by intention to treat. The primary outcomes were low birthweight (<2500 g), pre-eclampsia/eclampsia, severe postpartum anaemia (<90 g/L haemoglobin), and treated urinary-tract infection. There was an assessment of quality of care and an economic evaluation. FINDINGS: Women attending clinics assigned the new model (n=12568) had a median of five visits compared with eight within the standard model (n=11958). More women in the new model than in the standard model were referred to higher levels of care (13.4% vs 7.3%), but rates of hospital admission, diagnosis, and length of stay were similar. The groups had similar rates of low birthweight (new model 7.68% vs standard model 7.14%; stratified rate difference 0.96 [95% CI -0.01 to 1.92]), postpartum anaemia (7.59% vs 8.67%; 0.32), and urinary-tract infection (5.95% vs 7.41%; -0.42 [-1.65 to 0.80]). For pre-eclampsia/eclampsia the rate was slightly higher in the new model (1.69% vs 1.38%; 0.21 [-0.25 to 0.67]). Adjustment by several confounding variables did not modify this pattern. There were negligible differences between groups for several secondary outcomes. Women and providers in both groups were, in general, satisfied with the care received, although some women assigned the new model expressed concern about the timing of visits. There was no cost increase, and in some settings the new model decreased cost. INTERPRETATIONS: Provision of routine antenatal care by the new model seems not to affect maternal and perinatal outcomes. It could be implemented without major resistance from women and providers and may reduce cost.
Asunto(s)
Recien Nacido Prematuro , Mortalidad Materna/tendencias , Bienestar Materno , Complicaciones del Embarazo/prevención & control , Atención Prenatal/métodos , Atención Prenatal/estadística & datos numéricos , Organización Mundial de la Salud , Adulto , Argentina/epidemiología , Intervalos de Confianza , Cuba/epidemiología , Femenino , Humanos , Incidencia , Recién Nacido , Modelos Organizacionales , Cooperación del Paciente , Satisfacción del Paciente , Embarazo , Complicaciones del Embarazo/epidemiología , Atención Prenatal/normas , Valores de Referencia , Factores de Riesgo , Arabia Saudita/epidemiologíaRESUMEN
The World Health Organisation and collaborating institutions in developing countries are conducting a multicentre randomised controlled trial to evaluate a new antenatal care (ANC) programme, consisting of tests, clinical procedures and follow-up actions scientifically demonstrated to be effective in improving maternal and newborn outcomes. These activities are distributed, for practical reasons, over four visits during the course of pregnancy and are aimed at achieving predetermined goals. The study is taking place in four countries, Argentina, Cuba, Saudi Arabia and Thailand. Recruitment of study subjects started on 1 May 1996. All 53 ANC clinical units had been enrolled by December 1996. Clinics in each country were randomly allocated (cluster randomisation) to provide either the new programme or the traditional programme currently in use. Approximately 24,000 women presenting for ANC at these clinics over an average period of 18 months will have been recruited. As women attending the control clinics receive the 'best standard treatment' as currently offered in these clinics, individual informed consent is requested only from women attending the intervention clinics. Authorities of the corresponding health districts and all participating clinics have provided written institutional informed consent before randomisation. The primary outcome of the trial in relation to maternal conditions is the rate of a morbidity indicator index, defined as the presence of at least one of the following conditions for which ANC is relevant: (a) pre-eclampsia or eclampsia during pregnancy or within 24 h of delivery; (b) postpartum anaemia (haemoglobin < 90 g/L); or (c) severe urinary tract infection/pyelonephritis, defined as an episode requiring antibiotic treatment and/or hospitalisation. The primary fetal outcome is the rate of low birthweight (< 2500 g). Adverse maternal and fetal outcomes are expected for approximately 10% of the control group. Several maternal and perinatal secondary outcomes are also considered. A comprehensive cost-effectiveness analysis and women's and providers' satisfaction evaluation are performed concurrently with the trial. Health-care programmes should be rigorously evaluated by randomised controlled trials, which are feasible in developing countries and should be conducted before introducing new treatments or health interventions.
PIP: The procedures and examinations included in currently practiced prenatal care have not been subjected to systematic, scientifically rigorous evaluation. The World Health Organization (WHO) Antenatal Care Randomized Controlled Trial is evaluating a new prenatal care regimen with demonstrated efficacy in improving maternal and newborn outcomes. Program activities include screening for health conditions that increase the risk of specific adverse pregnancy outcomes, therapeutic interventions known to affect these outcomes beneficially, and education of pregnant women regarding potential health emergencies and appropriate responses. The study's hypothesis is that the tests, clinical procedures, and follow-up actions associated with this approach, delivered over the course of four visits during pregnancy, are more effective than the traditional prenatal care package in terms of specific maternal and perinatal results without being more expensive. This paper addresses the rationale, design, and methodology of this trial. 53 prenatal care clinics in four well-defined geographic areas (Khon Kaen Province, Thailand; Havana, Cuba; Rosario, Argentina; and Jeddah, Saudi Arabia) have been randomized to the two arms of the study. By the end of 1997, 24,000 women presenting for prenatal care at these sites had been enrolled. The primary maternal outcome is the morbidity indicator index, defined as the presence of at least one of the following conditions: pre-eclampsia or eclampsia during pregnancy or within 24 hours of delivery, postpartum anemia, or severe urinary tract infection/pyelonephritis. The primary fetal outcome is the rate of low birth weight. A comprehensive cost-effectiveness analysis and provider satisfaction evaluation will be performed concurrently with the trial. Data collection will be completed in 1998.
Asunto(s)
Investigación sobre Servicios de Salud/organización & administración , Estudios Multicéntricos como Asunto , Atención Prenatal/organización & administración , Ensayos Clínicos Controlados Aleatorios como Asunto , Proyectos de Investigación , Organización Mundial de la Salud , Argentina , Cuba , Países en Desarrollo , Femenino , Humanos , Selección de Paciente , Embarazo , Resultado del Embarazo , Arabia Saudita , TailandiaRESUMEN
We discuss methodological issues arising in a recent evaluation trial of a new antenatal care programme, as sponsored by the Special Programme of Research, Development and Research Training in Human Reproduction, and WHO's Division of Reproductive Health (Technical Support). The randomisation unit for the trial is the antenatal care clinic, with 53 clinics located in four countries randomly allocated to provide either the new programme or the traditional programme currently in use. Approximately 24,000 women presenting for antenatal care over an average period of 18 months will have been recruited.
PIP: The World Health Organization (WHO) Antenatal Care Randomized Controlled Trial is evaluating the impact of a new program of prenatal care on the health of mothers and newborns. Study subjects will receive either the standard prenatal care program currently offered at participating sites or a new regimen comprised of scientifically evaluated, objective-oriented prenatal care services. A total of 24,000 pregnant women from 53 prenatal care clinics in Argentina, Cuba, Thailand, and Saudi Arabia have been enrolled and stratified on the basis of the number of pregnant women enrolled in each clinic during the year preceding the study, the type of clinic (free-standing or hospital), and the administrative health system to which they belong. This article discusses methodological issues related to the study's design, with emphasis on sample size considerations, planned approaches to the statistical analysis, and data quality control. The rationales for selecting clinics as the unit of randomization are to reduce the risk of treatment contamination, encourage participation, and facilitate administrative and logistic convenience in the implementation of the intervention. Randomization of intact clinics to different intervention groups with predefined strata reflects the fact that the aim of the trial is to show the equivalence, not necessarily the superiority, of the new prenatal care program with the existing program of standard care. The two major adverse outcomes, a high maternal morbidity index and low birth weight, are expected to be in the range of 10%. To ensure that a statistically nonsignificant effect can be interpreted meaningfully, the trial has been designed to have a 90% power for ruling out an absolute difference of at least 0.02 in the expected incidence of the primary end points. A confidence interval approach was selected for sample size estimation, as recommended for equivalence trials, to provide additional assurance that the sample size is adequate.
Asunto(s)
Investigación sobre Servicios de Salud/métodos , Estudios Multicéntricos como Asunto/métodos , Atención Prenatal/organización & administración , Ensayos Clínicos Controlados Aleatorios como Asunto/métodos , Proyectos de Investigación , Organización Mundial de la Salud , Argentina , Cuba , Recolección de Datos/métodos , Interpretación Estadística de Datos , Femenino , Humanos , Selección de Paciente , Embarazo , Arabia Saudita , TailandiaRESUMEN
In the preparation of a randomised controlled trial to evaluate a new programme of antenatal care (ANC) in different parts of the world, we conducted a baseline survey of the ANC procedures in all 53 clinics participating in the trial. There were two components of this survey: (1) description of clinic characteristics and services offered: the staff of each clinic was interviewed and direct observation was made by field supervisors, and (2) the actual use of services by pregnant women attending these clinics: we reviewed a random sample of 2913 clinical histories. The clinical units surveyed were offering most of the activities, screening, laboratory tests and interventions recommended as effective according to the Cochrane Pregnancy and Childbirth Database (PCD), although some of these were not available in some sites. On the other hand, some tests and interventions that are considered not effective according to these criteria are reportedly offered. There was a difference across sites in the availability and offer to low-risk women of vaginal examination, evaluation of pelvic size, dental examination, external version for breech presentation and formal risk score classification, and a notable difference in the type of principal provider of ANC. There was a large variation in the actual use of screening and laboratory tests and interventions that should be offered to all women according to Cochrane PCD criteria: some of these are simply not available in a site; others are available, but only a fraction of women attending the clinics are receiving them. The participating sites all purport to follow the traditional 'Western' schedule for ANC, but in three sites we found that a high percentage of women initiate their ANC after the first trimester, and therefore do not have either the recommended minimum number of visits during pregnancy or the minimum first trimester evaluation. It is concluded that the variability and heterogeneity of ANC services provided in the four study sites are disturbing to the profession and cast doubts on the rationale of routine ANC.
PIP: This paper reports the results of an antenatal care (ANC) baseline survey in four study sites in different parts of the world participating in the WHO ANC randomized controlled trial. The health care units surveyed are providing most of the activities, screening, laboratory tests and interventions recommended as effective based on the Cochrane Pregnancy and Childbirth Database (PCD), although some of these are not available in some clinics. Some tests and interventions that are considered ineffective according to the PCD criteria are reportedly offered. A variation is observed across sites in the availability and offer to low-risk women of vaginal exam, pelvic size assessment, dental exam, external version for breech presentation, and formal risk score classification. Moreover, there is a significant difference in the type of principal ANC provider and a great variation in the actual performance of screening and laboratory tests and interventions that should be provided to all women according to these criteria. This is partly due to the unavailability of these services in the site, or only a fraction of women attending the clinics are receiving them. The participating clinics all declared to follow the traditional Western schedule for ANC; however, three clinics are found to have a high percentage of women who begin their ANC after the first trimester of pregnancy. It is generalized that the variability and heterogeneity of ANC services offered in the four sites are annoying to the profession and cast doubts on the rationale behind routine ANC.