The methodological challenges of attempting to compare the safety of home and hospital birth in terms of the risk of perinatal death

Abstract

This paper identifies a number of methodological difficulties associated with the comparison of home and hospital birth in terms of the risk of perinatal death, and suggests ways in which these problems can be overcome. A review of recent studies suggests that most available data sources are unable to overcome all of these challenges, which is one of the reasons why the debate about whether perinatal death is more likely if a home birth is planned or if a hospital birth is planned has not been satisfactorily resolved. We argue that the debate will be settled only if perinatal mortality data from a sufficiently large number of maternity care providers over a sufficiently long period of time can be pooled and made available for analysis. The pooling of data will bring about its own difficulties due to variations over time and between providers and geographical areas, which would need to be taken into account when analysing pooled data. However, given the impracticality of a randomised controlled trial and the rarity of home birth in most of the Western world, we argue that more effort should be made to pool data for perinatal mortality and other rare pregnancy outcomes, and share them between health providers and researchers. Thus, high-quality analyses could be conducted, allowing all women to make an informed choice about place of birth. However, pooling data from countries or states with very different maternity care systems should be avoided.

Maternal and perinatal mortality by place of delivery in sub-Saharan Africa: a meta-analysis of population-based cohort studies

“…Few studies report on the impact of place of delivery on maternal and perinatal mortality in SSA, probably reflecting the pragmatic and ethical difficulties of conducting such studies [ 24 ]. To date we are unaware of any randomized control trial (RCT), which would allow causal inference.…”

Investigating the debate of home birth safety: A critical review of cohort studies focusing on selected infant outcomes

“…This is one of multiple reviews and commentaries that has been written to examine the safety of planned home birth (Chervenak et al ., ; Fullerton, Navarro, & Young, ; Kingma, ; Olsen & Clausen, ; Wax et al ., ,). Previous articles typically focus on mortality, but some address other outcomes such as transfers and study methods (Blix et al ., ; Nove, Berrington, & Matthews, ; Wax et al ., ). The current review differs from the existing articles due to a focus on the strengths and limitations of the included studies.…”

The ResQu Index: A new instrument to appraise the quality of research on birth place

“…Item generation was informed by a literature review and the principles proposed by Vedam [ 45 ], Hutton [ 51 ] and Nove [ 47 ]. Each item was selected to be consistent with other systems for appraisal of research quality [ 34 , 35 , 37 , 38 , 52 ] but adapted, when necessary, to focus on the unique aspects of comparing outcomes across birth settings.…”

“…place of birth), integrity of data, appropriateness of sample size and selection, transparency of methods and comparability of cohorts. Other items relate specifically to studies of birth place as outlined by Vedam [ 49 ] and Nove [ 47 ], and to address issues identified as problematic in critiques of previous research in this field [ 43 , 44 , 46 ]. These items include identifying the timing of birth place decisions in relation to an intention-to-treat model and ensuring that studies of home birth clearly distinguish data from planned home births with skilled attendants, from data generated by unplanned home births or “free births” without professional support.…”

“…Following revelations of critical flaws in some published studies [ 43 – 46 ], researchers developed key principles for appraising the quality of research on place of birth [ 45 , 47 – 49 ]. Our team designed the Birth Place Research Quality Index (ResQu Index) as a quantitative scoring system based on these key principles, as well as best practices for critical appraisal of research [ 39 , 50 ].…”