Study	Reason for exclusion
Botha 1968	This was not a randomised controlled trial. "A series of cases including 60 unselected, consecutive normal deliveries were divided to two groups.."
Giacalone 2000	CCT was practiced differently between the two arms ‐ therefore this study does not meet the inclusion criteria. It appears that the intervention group had cord drainage along with CCT but the control group had spontaneous expulsion of placenta after observing the signs of separation.
Gulati 2001	This was not indicated as being a randomised controlled trial. Although this study shows a reduced length of the third stage of labour and less amount of blood loss in the cord drainage group compared with the control group, there is no indication of a randomised allocation of participants to each group.The methods describe very briefly: "The study was carried out on 200 pregnant women...admitted in the labour ward..."
Johansen 1971	This was a quasi‐randomised study, as methods describes: "200 women of comparable age, parity...were studied...the control group comprised 110 women born on odd dates and the study group comprised of 90 women born on even dates."
Moncrieff 1986	Inadequate reporting; not enough details reported to evaluate the quality of the research and randomisation process/not possible to contact the authors for more details.
Navaneethakrishnan 2007	The main reasons include inadequate reporting being an abstract and inclusion of caesarean section deliveries. In addition, the main objective of this study was to determine whether placental cord drainage reduces the size of fetomaternal transfusion in rhesus negative women, no other outcomes were reported.
Razmkhah 1999	This was a quasi‐randomised study as it is described in the text: "This study is a semi‐experimental investigation in which 147 women in labor were placed randomly in two groups: experimental (placental end of umbilical cord open) and control (placental end of umbilical cord closed)". "[No more information about randomisation has been provided.]"
Terry 1970	This was a quasi‐randomised study. Cases were allocated alternately.
Thomas 1990	The main issue that undermines the reliability of this paper includes a series of reporting bias. The authors initially explain that all participants had early cord clamping, although data in table 1, indicate that almost half of all participants had cord clamping after cord pulsation ceased. The other confusing matter is how they have labelled the intervention group as "late cord clamping" and the control group as "early clamping" (table 1). The timing of cord clamping is a confounding factor. In addition, the cord drainage group has not exclusively had delayed cord clamping, there seems to be some confusion in defining the groups in the study. Also, the outcomes of interest have not reported (PPH) or defined (e.g. manual removal of placenta or retained placenta) in a standard way.

CCT:controlled cord traction 
 PPH: postpartum haemorrhage