Bed rest in singleton pregnancies for preventing preterm birth

Based on the limited data available, bed rest for the prevention of preterm birth can neither be recommended nor refuted.

RHL Commentary by Qureshi Z

1. EVIDENCE SUMMARY

This review (1) assessed the effect of bed rest at home or in hospital for the prevention of preterm labour in women with singleton pregnancies at high risk of preterm birth. Only one study (2) – a cluster randomized trial – met the inclusion criteria. The study participants (women at high risk of preterm birth) were offered prescription of bed rest; progestin; social support; placebo and no intervention. For the purpose of comparing the effects of bed rest to no bed rest, 432 women allocated to bed rest at home were compared with a control group of 834 women, of whom 412 had received a placebo and 422 had received no intervention. Incidence of preterm birth prior to 37 weeks was similar in both groups: 7.9% in the intervention group compared with 8.5% in the control group, with a relative risk of 0.92 and 95% confidence interval of 0.62–1.37.

The review authors noted methodological problems with the study with regard to randomization, particularly allocation concealment. Besides, the evaluation of bed rest was a secondary objective of the study.

In the review there is a discrepancy between a set of figures presented in two different places, namely the results section and in a table. Also, the author’s conclusion relates to bed rest at home as well in hospital, whereas participants in the included study were on bed rest at home only.

The authors concluded that based on the available evidence bed rest for the prevention of preterm birth could neither be recommended nor refuted.

2. RELEVANCE TO UNDER-RESOURCED SETTINGS

2.1. Magnitude of the problem

Preterm birth is an important public health problem worldwide. Its consequences are especially serious in economically disadvantaged communities. In 2000, at our tertiary-level hospital in Nairobi, Kenya, the prevalence of preterm births was 15.2% (3) – a rate quite similar to that (16%) found at Harare Hospital, Harare, Zimbabwe, in 1998 (4).

In most sub-Saharan countries the largest contributor to perinatal mortality is preterm birth. In an assessment of perinatal mortality, done in seven developing countries in the WHO calcium supplementation trial for the prevention of pre-eclampsia in pregnant women with low calcium dietary intake, spontaneous preterm delivery was the most common obstetric event leading to perinatal death (28.7%) and prematurity was the main cause of early neonatal deaths (62%) (4, 5). Thus, it is of utmost importance to diagnose, prevent, and treat this condition to mitigate its impact on neonatal morbidity and mortality.

Neonatal facilities to support preterm infants are inadequate even at the tertiary level of health care in under-resourced settings, as evidenced by the high rates of neonatal mortality among preterm infants observed in the WHO calcium supplementation trial (5).

2.2. Applicability of the results

The results of the review are inconclusive regarding the benefit of bed rest for prevention of preterm labour. The only study included in the review was conducted in the USA, where extensive investigations are likely to have been performed to rule all possible causes of preterm labour. One has to consider the etiology of preterm labour to create a model of how bed rest could prevent it, and whether this would be different in the developed and under resourced world.

A related Cochrane review (6) that evaluated the benefits of hospitalization and bed rest for multiple pregnancy concluded there was not enough evidence to support a policy of routine hospitalization for bed rest; the review found that this intervention neither improved the rates of preterm birth nor perinatal mortality: Therefore, for singleton pregnancy, unless the woman has cervical incompetence, prescribing bed rest cannot be justified. However, a case–control study in the Republic of Benin found that although per se working during pregnancy did not increase the risk of preterm labour, carrying heavy loads and working more than five days per week was significantly associated with preterm birth (7). Therefore, in the context of the circumstances of individual women in under-resourced settings, it may be prudent to advise women to reduce physical labour during pregnancy.

2.3. Implementation of the intervention

In resource-constrained settings, reduction in physical activity and avoidance of hard work especially for women poses a major challenge to the immediate survival of the women’s family. In these settings, women have to work to provide resources for the usually large families and if they stop working, this might pose immediate danger of dying from hunger, starvation and poverty. Most women have to work on farmlands, walk long distances to fetch water and firewood, cook, care of the children and at the same time, harvest and transport family food to their homes. A woman’s income may be the major contributor or even the only source of income for the family

Bed rest in hospital for this condition has not been evaluated in Kenya and most other countries in the sub-Saharan region, with chronic staff shortage and lack of bed space for even other more deserving conditions this would not even are feasible. For those developing counties that have a fee for service for hospitalization would also compound the issue, since there would also be loss of income during this time.

3. RESEARCH

The problem of preterm birth is multi-etiologic. The term 'bed rest' as an intervention needs to be defined more clearly – e.g. in terms of number of hours per day of immobility. The postulated mechanism by which bed rest may prevent preterm birth also needs to be defined clearly and whether or not hard work and hard physical labour during pregnancy contribute to preterm birth.

The challenge is to find a more specific intervention that is researchable. In this regard it would be important to identify all the risk factors for preterm birth and possible risk prevention interventions. Secondly, there would be a need to conduct in each population randomized controlled trials for specific interventions.

Sources of support: None

Acknowledgement: Dr Kizito Lubano (MBChB, M.MED, MSc) Research Officer, Reproductive Health Research Unit, Kenya Medical Research Institute

References

  • Sosa C, Althabe F, Belizán J, Bergel E. Bed rest in singleton pregnancies for preventing preterm birth. Cochrane Database of Systematic Reviews 2004, Issue 1. Art. No.: CD003581. DOI: 10.1002/14651858.CD003581.pub2.
  • Hobel CJ, Ross MG, Bemis RL, Bragonier JR, Nessim S, Sandhu M, et al. The West Los Angeles Preterm Birth Prevention Project. I. Program impact on high-risk women. Am J Obstet Gynecol 1994;170:54-62.
  • Irungu M. Demographic and obstetric factors associated with delivery of pre-term infants at Kenyatta National Hospital. Master of Medicine Thesis, University of Nairobi, Nairobi, Kenya, 2001.
  • Feresu SA, Harlow SD, Welch K, Gillespie BW. Incidence of and socio-demographic risk factors for stillbirth, preterm birth and low birthweight among Zimbabwean women. Paediatr Perinat Epidemiol 2004;18:154-63.
  • Ngoc NT, Merialdi M, Abdel-Aleem H, Carroli G, Purwar M, Zavaleta N, et al. Causes of stillbirths and early neonatal deaths: data from 7993 pregnancies in six developing countries. Bull World Health Organ 2006;84:699-705.
  • Crowther CA. Hospitalisation and bed rest for multiple pregnancy. Cochrane Database of Systematic Reviews 1997, Issue 3. Art. No.: CD000110. DOI: 10.1002/14651858.CD000110.
  • Agbla F, Ergin A, Boris NW. Occupational working conditions as risk factors for preterm birth in Benin, West Africa. Rev Epidemiol Sante Publique. 2006 Apr;54(2):157-65

This document should be cited as: Qureshi Z. Bed rest in singleton pregnancies for preventing preterm birth : RHL commentary (last revised: 31 August 2007). The WHO Reproductive Health Library; Geneva: World Health Organization.

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