Preventing and managing prematurity

Planned home versus hospital care for preterm prelabour rupture of the membranes (PPROM) prior to 37 weeks' gestation

BACKGROUND

Preterm prelabour rupture of membranes (PPROM) is associated with increased risk of maternal and neonatal morbidity and mortality. Women with PPROM have been predominantly managed in hospital. It is possible that selected women could be managed at home after a period of observation. The safety, cost and women's views about home management have not been established.

OBJECTIVES

To assess the safety, cost and women's views about planned home versus hospital care for women with PPROM.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 July 2013) and the reference lists of all the identified articles.

SELECTION CRITERIA

Randomised and quasi-randomised trials comparing planned home versus hospital management for women with PPROM before 37 weeks' gestation.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed clinical trials for eligibility for inclusion, risk of bias, and carried out data extraction.

MAIN RESULTS

We included two trials (116 women) comparing planned home versus hospital management for PPROM. Overall, the number of included women in each trial was too small to allow adequate assessment of pre-specified outcomes. Investigators used strict inclusion criteria and in both studies relatively few of the women presenting with PPROM were eligible for inclusion. Women were monitored for 48 to 72 hours before randomisation. Perinatal mortality was reported in one trial and there was insufficient evidence to determine whether it differed between the two groups (risk ratio (RR) 1.93, 95% confidence interval (CI) 0.19 to 20.05).  There was no evidence of differences between groups for serious neonatal morbidity, chorioamnionitis, gestational age at delivery, birthweight and admission to neonatal intensive care.There was no information on serious maternal morbidity or mortality. There was some evidence that women managed in hospital were more likely to be delivered by caesarean section (RR (random-effects) 0.28, 95% CI 0.07 to 1.15). However, results should be interpreted cautiously as there is moderate heterogeneity for this outcome (I² = 35%). Mothers randomised to care at home spent approximately 10 fewer days as inpatients (mean difference -9.60, 95% CI -14.59 to -4.61) and were more satisfied with their care. Furthermore, home care was associated with reduced costs.

AUTHORS' CONCLUSIONS

The review included two relatively small studies that did not have sufficient statistical power to detect meaningful differences between groups. Future large and adequately powered randomised controlled trials are required to measure differences between groups for relevant pre-specified outcomes. Special attention should be given to the assessment of maternal satisfaction with care and cost analysis as they will have social and economic implications in both developed and developing countries.

Planned home versus hospital care for preterm prelabour rupture of the membranes (PPROM) prior to 37 weeks' gestation

BACKGROUND

Preterm prelabour rupture of membranes (PPROM) is associated with increased risk of maternal and neonatal morbidity and mortality. Women with PPROM have been predominantly managed in hospital. It is possible that selected women could be managed at home after a period of observation. The safety, cost and women's views about home management have not been established.

OBJECTIVES

To assess the safety, cost and women's views about planned home versus hospital care for women with PPROM.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (January 2010) and the reference lists of all the identified articles.

SELECTION CRITERIA

Randomised and quasi-randomised trials comparing planned home versus hospital management for women with PPROM before 37 weeks' gestation.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed clinical trials for eligibility for inclusion, risk of bias, and carried out data extraction.

MAIN RESULTS

We included two trials (116 women) comparing planned home versus hospital management for PPROM. Overall, the number of included women in each trial was too small to allow adequate assessment of pre-specified outcomes. Investigators used strict inclusion criteria and in both studies relatively few of the women presenting with PPROM were eligible for inclusion. Women were monitored for 48 to 72 hours before randomisation. Perinatal mortality was reported in one trial and there was insufficient evidence to determine whether it differed between the two groups (risk ratio (RR) 1.93, 95% confidence interval (CI) 0.19 to 20.05). There was no evidence of differences between groups for serious neonatal morbidity, chorioamnionitis, gestational age at delivery, birthweight and admission to neonatal intensive care.There was no information on serious maternal morbidity or mortality. There was some evidence that women managed in hospital were more likely to be delivered by caesarean section (RR (random-effects) 0.28, 95% CI 0.07 to 1.15). However, results should be interpreted cautiously as there is a moderate heterogeneity for this outcome (I(2) = 35%). Mothers randomised to care at home spent approximately 10 fewer days as inpatients (mean difference -9.60, 95% CI -14.59 to -4.61) and were more satisfied with their care. Furthermore, home care was associated with reduced costs.

AUTHORS' CONCLUSIONS

The review included two relatively small studies that did not have sufficient statistical power to detect meaningful differences between groups. Future large and adequately powered randomised controlled trials are required to measure differences between groups for relevant pre-specified outcomes. Special attention should be given to the assessment of maternal satisfaction with care and cost analysis as they will have social and economic implications in both developed and developing countries.

Differences and trends in obstetric interventions at term among urban and rural women in New South Wales: 1990-1997

The aim of this study was to compare the management of term births among rural and urban women, including the effect of indigenous status and out-of-area-birth for rural women. Data were obtained from the NSW Midwives Data Collection (MDC), on 619,298 women who gave birth to a live, singleton infant at term (37-45 weeks gestation) from 1 January 1990 to 31 December 1997. Compared with urban non-indigenous women, rural women and indigenous women had lower rates of obstetric interventions both before birth (induction of labour, planned Caesarean section and epidural) and at the time of birth (Caesarean after labour, instrumental delivery and episiotomy). This was especially true for rural women giving birth in the their local area. The differing pregnancy risk profile of rural women did not explain the differences in intervention rates but differences were partly explained by higher rates of epidural anaesthesia in urban areas.

Antenatal transfer of rural women to perinatal centres. High Risk Obstetric and Perinatal Advisory Working Group

The aim of this study was to describe antenatal transfers of rural women to perinatal centres, and among transferred women, to assess the use of selected evidence-based therapies and determine the predictors of preterm and imminent births. The clinical records of rural women antenatally transferred to perinatal centres in NSW and the ACT during 1997-1998 were reviewed. Of 453 rural antenatal transfers, 408 (90%) were emergency transfers. Increasing remoteness was associated with increased rates of antenatal transfer but not with a lower probability of giving birth. Of all transferred women, 64% delivered; 58% of preterm transfers delivered preterm and of those delivering preterm, 76% delivered within 7 days. Although the main reason for antenatal transfer was the possibility of preterm birth, women presenting with preterm contractions only were less likely to deliver preterm (OR = 0.2, 95% CI 0.1-0.4) or < or = 7 days (OR = 0.3, 95% CI 0.2-0.5) than women with any other presenting symptoms. The overall usage of effective interventions (antenatal steroids, antibiotics for PPROM and beta-mimetic tocolysis to delay birth) among antenatally transferred rural women was high, but there is room for increased uptake prior to transfer.

Socio-economic disparities in pregnancy outcome: why do the poor fare so poorly?

In this paper, we review the evidence bearing on socio-economic disparities in pregnancy outcome, focusing on aetiological factors mediating the disparities in intrauterine growth restriction (IUGR) and preterm birth. We first summarise what is known about the attributable determinants of IUGR and preterm birth, emphasising their quantitative contributions (aetiological fractions) from a public health perspective. We then review studies relating these determinants to socio-economic status and, combined with the evidence about their aetiological fractions, reach some tentative conclusions about their roles as mediators of the socio-economic disparities. Cigarette smoking during pregnancy appears to be the most important mediating factor for IUGR, with low gestational weight gain and short stature also playing substantial roles. For preterm birth, socio-economic gradients in bacterial vaginosis and cigarette smoking appear to explain some of the socio-economic disparities; psychosocial factors may prove even more important, but their aetiological links with preterm birth require further clarification. Research that identifies and quantifies the causal pathways and mechanisms whereby social disadvantage leads to higher risks of IUGR and preterm birth may eventually help to reduce current disparities and improve pregnancy outcome across the entire socio-economic spectrum.

Very and moderate preterm births: are the risk factors different?

OBJECTIVE

To describe the risk factors for very preterm births and to compare the strengths of the associations between these risk factors and very and moderate preterm births.

DESIGN

A case-control study.

SETTING

Fifteen European countries.

METHODS

Between 1994 and 1997, 1675 very preterm births, 3652 moderate preterm births and an unmatched control group of 7965 births at term were included. Odds ratios for very and moderate preterm births (related to socioeconomic status, behavioural factors, maternal age, body mass index and obstetric history) were estimated and compared using polytomous logistic regression.

RESULTS

Underprivileged social situation, older maternal age and adverse previous pregnancy outcomes were significantly related to very and moderate preterm births. However, these factors were more strongly associated with very preterm births than with moderate preterm births, for both spontaneous and induced deliveries. Smoking during pregnancy, young maternal age and low body mass index were significantly related to very and moderate spontaneous preterm births, but no significant difference in odds ratios was observed between the two outcomes.

CONCLUSION

These results suggest that risk factors for very and moderate preterm births are similar, but the strength of the associations differ, especially for social factors and obstetric history.

Low-birthweight prevention programs: the enigma of failure

BACKGROUND

Low birthweight is the primary cause of neonatal morbidity and mortality in the United States. The purpose of our study was to identify factors associated with the effectiveness and apparent ineffectiveness of comprehensive, multicomponent, prenatal care programs for preventing low birthweight.

METHODS

We reviewed obstetric, pediatric, and public health program evaluations, research reports, and commentaries, published in the English language literature, over the last four decades that pertained to the efficacy of prenatal care for preventing low birthweight.

RESULTS

The heterogeneous nature of the services delivered and the lack of consistency in the definition of variables made it impossible to use rigorous, quantitative techniques to summarize this evaluation of the literature. Two general limitations of research design that emerged from our reviews were the focus on clusters of commonly associated risk factors, which has blurred the causal pathways linking specific risk factors to low birthweight, and the failure to examine process variables. These two methodologic problems have led investigators to erroneous conclusions that overstate the significance of negative intervention outcomes. The success and failure of low-birthweight prevention programs has rarely been examined in relation to evidence that the intervention actually modified the targeted risk factors.

CONCLUSIONS

Few rigorous evaluations of well-designed programs have been conducted. Without an improvement in intervention designs and evaluation studies, recommendations to support or curtail the funding of comprehensive, multicomponent prenatal care services are inappropriate. Rigorously obtained evidence of the costs and benefits of approaches to the prevention of low birthweight are sorely needed.

Very preterm birth--a regional study. Part 1: Maternal and obstetric factors

OBJECTIVE

To ascertain the demographic, pregnancy and obstetric factors associated with the delivery of a liveborn very preterm infant ( < 33 weeks of gestation) and to investigate any differences in these factors between identifiable aetiological groups.

DESIGN

Cohort analytical study.

SETTING

King Edward Memorial Hospital for Women (KEMH), Western Australia.

MAIN VARIABLES EXAMINED

Maternal demographic and obstetric history, primary complication associated with delivery, obstetric management and mode of delivery.

RESULTS

Six hundred and eight women who were delivered of 693 liveborn very preterm infants in Western Australia between 1.1.90 and 31.12.91, representing 1.22% of all women who were delivered of a liveborn infant in those years. Singleton pregnancy occurred in 517 (85%) and 541 (89%) were delivered in KEMH. Mean maternal age was 28 years with an excess of mothers less than 20 years of age and older than 34 years compared with the statewide perinatal data. Pre-eclampsia (n = 128, 21.1%), preterm prelabour rupture of membranes (n = 148, 24.3%), idiopathic preterm labour (n = 195, 30.4%) and antepartum haemorrhage (n = 111, 18.3%) were associated with 94.1% of deliveries. These proportions varied with plurality and period of gestation. Demographic details, use of antenatal steroids, exposure to labour and caesarean section delivery differed between mothers depending on the primary complication. Overall 322 (53.0%) received antenatal steroids and 297 (48.8%) were delivered by caesarean section. Factors associated with decreased use of steroids were gestational age of less than 27 weeks (odds ratio (OR) 0.54; 95% CI 0.36-0.83), preterm prelabour rupture of the membranes (OR 0.48; 95% CI 0.29-0.78) and idiopathic preterm labour (OR 0.56; 95% CI 0.35-0.91). Factors associated with increased use of steroids were multiple pregnancy (OR 1.70; 95% CI 1.02-2.81) and pre-eclampsia (OR 1.87; 95% CI 1.09-3.19).

CONCLUSIONS

These very preterm deliveries account for only a small proportion of all deliveries. There are differences in the mother's demographic history, obstetric management and delivery depending on the primary aetiological factor.

The epidemiology of preterm birth

Secular trends in the prevalence of preterm birth and international comparisons of the rates of preterm birth are difficult to interpret because of differences, both formal and informal, in the registration of extremely preterm births. Accurate estimation of gestational age is another problem in the measurement of preterm birth. Preterm birth is heterogeneous in several ways. It is heterogeneous in terms of the extent to which the birth is preterm (20-27 weeks, 28-31 weeks or 32-36 weeks of gestation); in whether the birth was elective or spontaneous; and among spontaneous idiopathic preterm births, in whether there was preterm labour or premature rupture of the membranes. Case-control study designs taking account of these subgroups have been a recent feature of epidemiologic approaches. The classic social associations of preterm birth--low socioeconomic status, extremes of maternal age, primiparity, being unmarried--apply to extremely preterm and moderately preterm births as well as to the mildly preterm group. The strength of these associations is small compared with factors in the prior reproductive history and with medical and obstetric complications of the current pregnancy. Recent epidemiological research activities have focused on the ways in which risk factors such as physical workload, drugs and alcohol, lack of social support and infection might be mediating factors between sociodemographic status and preterm birth. As Eastman (1947) pointed out almost 50 years ago, 'only when the factors causing prematurity are clearly understood can any intelligent attempt at prevention be made'.