Comparisons of benefits and risks of single embryo transfer versus double embryo transfer: a systematic review and meta-analysis

Table 2 Overall analyses of secondary outcomes between SET and DET in a single cycle

Index	Studies no.	SET total	DET total	I²	OR/WMD (95%CI)	P value
Maternal pregnancy outcomes and complications
CPR	60	43,414	68,289	82%	0.78 (0.71-0.85)	< 0.001
Miscarriage rate	43	5230	13,249	30%	1.10 (0.95-1.27)	0.211
Perinatal mortality rate	7	1135	1970	0%	0.71 (0.25-2.06)	0.532
Cesarean rate	3	238	698	15%	0.64 (0.43-0.94)	0.024
GDM rate	1	76	103	–	0.45 (0.02-11.11)	0.623
PE rate	1	76	103	–	9.86 (0.50-193.72)	0.132
APH rate	1	76	103	–	0.35 (0.15-0.82)	0.016
Neonatal outcomes and complications
Delivery gestational age (week)	8	1136	1771	58%	0.88 (0.56-1.20)	< 0.001
Preterm birth rate^a	13	1852	2380	0%	0.25 (0.21-0.30)	< 0.001
Birth weight (g)	7	1164	2572	84%	297.47 (208.47-386.46)	< 0.001
Low birth weight rate	9	1360	2826	0%	0.20 (0.16-0.25)	< 0.001
Birth defect rate	3	964	1672	0%	1.32 (0.68-2.59)	0.414
Apgar1 < 7 rate	2	99	193	0%	0.12 (0.02-0.93)	0.042
NICU admission rate	2	99	193	0%	0.30 (0.14-0.66)	0.003

Note: ^apreterm birth rate was calculated as the number of preterm births divided by the total number of live births (multiple gestations included) in one of included studies (Sini 2020)
Abbreviation: 2SET Two consecutive elective single embryo transfer; APH Antepartum haemorrhage; CI Confidence interval; CPR Clinical pregnancy rate; DET Double embryo transfer; GDM Gestational diabetes; LBR Live birth rate; MBR Multiple birth rate; MPR Multiple pregnancy rate; NICU Neonatal intensive care unit; OR Odds ratio; PE Pre-eclampsia; WMD Weighted mean difference

ISSN: 1477-7827