Table C.2Excluded studies (planned home birth versus planned hospital birth)

AuthorsYearCountryReasons for exclusionValidity
Chamberlain311994UKAlthough reported as matched by age, lone parent status, parity and hospital, the sizes of the two groups were significantly different. There were over 1000 unmatched planned home birth women, but these women were included in the analysis. Socio-economic status and obstetric backgrounds of these two groups were reported as statistically significantly different; hence, the comparison was invalid. No regression analysis was used. The study reported perinatal mortality, but did not report IPPM.
Davies431993UKThis was a case series without a control group.
Caplan381980–1981UKWomen who gave birth at home were compared with a random sample of women who gave birth in hospital. Use of actual place of birth, rather than planned place of birth, and the lack of any controlling for background risk of these two groups made the comparison invalid.
Ford441977–1989UKThis was a case series without a control group.
Shearer391978–1983UK202 women who planned home birth were compared with 185 women who planned hospital birth. No control of background obstetric risks was attempted.
Tew371970UKAlthough regression modelling was used to control some of the confounding factors, these were comparing actual home birth with actual hospital birth. The study was conducted prior to 1980.
Johnson422000North AmericaThis was a case series without a control group.
Wiegers331990–1993NetherlandsThe study employed matched control design, comparing planned home birth and planned hospital birth women, although the outcome reported was ‘perinatal outcome index’ defined by the authors, and each relevant clinical outcome was not obtained.
Duran341971–1989USAAlthough regression modelling controlled some of the confounding factors, these were comparing actual home birth with actual hospital birth with completely different backgrounds. The control group was drawn from the 1980 US National Natality/National Fetal Mortality Survey, in which low birthweights and fetal deaths were deliberately oversampled.
Mehl40,411970sUSAAlthough regression modelling controlled some of the confounding factors, these were comparing actual home birth with actual hospital birth with significantly different backgrounds. The study was conducted prior to 1980.
Olsen272005N/AThis systematic review only included the Dowswell study.26 The included RCT does not report relevant outcomes for the clinical questions.
Olsen281997N/AThe author conducted meta-analyses of six observational studies, of which five are listed above.29,32–35 The other study was in a foreign language. The majority of the included studies had significant risk of introducing bias and/or confounding factors as above. In particular, the study by Duran34 was weighted the most in the meta-analysis owing to the size of the studies. The original study conducted a regression analysis, attempting to control background of these two different populations, although the raw data were used for this Olsen meta-analysis (see above).

From: Appendix C, Selection criteria and validity scores for included and excluded studies for the systematic review comparing planned home birth and planned hospital birth and the systematic review comparing planned standalone midwife-led unit and obstetric unit birth

Cover of Intrapartum Care
Intrapartum Care: Care of Healthy Women and Their Babies During Childbirth.
NICE Clinical Guidelines, No. 55.
National Collaborating Centre for Women's and Children's Health (UK).
London: RCOG Press; 2007 Sep.
Copyright © 2007, National Collaborating Centre for Women’s and Children’s Health.

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