1. Reporting of fetal, neonatal and perinatal death.

Trial	Fetal death (FD)	Intrapartum death	Stillbirth	Neonatal death (NND)	Perinatal death (PND)	Included inDodd 2013?	Decision for PND for multiples review?
Aboulghar 2012	‐	‐	‐	Reported as maternal outcome. From text appears as if at least one pregnancy affected by demise of both twins	‐	Yes	Cannot reliably convert maternal denominator for neonatal outcome. Data not included
Awwad 2015	Yes	‐	‐	‐	Yes, as a baby outcome.	N/A	Include
Cetingoz 2011	No death data	‐	‐	‐	‐	No PND reported	N/A
Serra 2013	Fetal death reported as maternal outcome and only as a single co‐twin demise outcome. Unsure if any pregnancies where both twins died	‐	‐	Yes, as a baby outcome	Not reported. Cannot convert fetal death into a baby outcome because only reported if single twin demise likely to underestimate	Yes	Data not included.
Norman 2009	Reported as a maternal outcome and denominator not clear	‐	‐	Yes	No	No	No
Rode 2011	Yes. as maternal outcome but specifies only 1 twin affected in each of those pregnancies	‐	‐	Yes	In text	Yes	Yes
Wood 2012	‐	‐	‐	‐	Yes, as infant outcome	N/A	Yes
Awwad 2015	‐	‐	Yes	Yes	Yes, as infant outcome	N/A	Yes
Briery 2009	‐	‐	‐	Yes	‐	No PND reported	N/A
Combs 2010triplets	‐	‐	‐	Yes	Yes	Yes	Yes
Combs 2011twins	‐	‐	‐	Yes	Yes	Yes	Yes
Hartikainen‐Sorri 1980	‐	‐	‐	‐	Yes in text	Yes	Yes
Lim 2011	‐	1 or more died during delivery after 24 wks and also any IUD before onset labour or onset delivery	Reported “all live births”	‐	No, and cannot be reliably added up from data presented	Yes	Data not included
Rouse 2007	Yes	‐	‐	Yes	Yes, from text (not in table)	No ‐ not sure why data not included	Yes
Senat 2013	Yes	Yes	‐	Yes	Can add NND and FD (IP and IU); all Ns clear	No ‐ not sure why data not included	Yes. Extrapolated from text and checked
Caritis 2009	Yes, as a maternal outcome	‐	‐	Yes	Cannot add FD and NND because FD reported as a maternal outcome	No	Data not included

IP: intrapartum
IU: intra‐uterine
IUD: intra‐uterine death
N/A: not applicable
wk: week