In 1984, Iain Chalmers (a perinatal epidemiologist) and Klim McPherson (a medical statistician/epidemiologist) and their families went to Zimbabwe for a mixture of work and holiday. Conversations with Ian Brown, their host and the professor of obstetrics in Harare, revealed that, some years earlier, there had been a controlled trial to assess the effects of routine hospitalization for bed rest in the third trimester of pregnancy for women with twin pregnancies. The study had been prompted by a shortage of antenatal hospital beds and uncertainty among obstetricians about whether the then current policy actually had its intended effects – to reduce the rate of preterm delivery. The trial had not shown any such effect, so, after the results had been presented at a local meeting of the Obstetrics and Gynaecology Society, the policy was abandoned.

Other than this local oral presentation, the study had never been reported. On enquiring whether the data were still available, Dr Michael Saunders, the principal investigator, produced a large, hand-written spreadsheet containing all the data. Iain Chalmers and Klim McPherson set about analysing it and produced a first draft of an article intended for publication. After several iterations with input from their Zimbabwean co-authors, a report was submitted to the Lancet. This included unpublished data obtained by Iain Chalmers from Dr Anna-Liisa Hartikainen-Sorri, an acquaintance in Oulu, Finland, who had conducted the only other similar trial that had been located. The Lancet paper was important because the combined analysis of these two trials suggested that, far from reducing the frequency of preterm delivery of twins, the policy of hospitalization for bed rest for twin pregnancies appeared to have the opposite effect.

By publishing this trial, the 212 women who participated have had their efforts counted. Read other stories of researchers publishing their old data in our recovered trials series.


Michael C Saunders, James S Dick, Ian McL Brown, Klim McPherson and Iain Chalmers: The effects of hospital admissions for bed rest on the duration of twin pregnancy: a randomised trial. Lancet 1985; 2:793-795. Abstract.