Changes in sex ratio from fertilization to birth in assisted-reproductive-treatment cycles

Table 2 Sex ratio (XY/XX) at birth of singleton deliveries according to the method of fertilization applied and the day of embryo transfer

Method of fertilization	Day of embryo transfer	Sex ratio	References^a
IVF	≤ Day 3^b	0.98 (1929/1968)	[23]
		1.08 (2084/1932)	[24]
	Total: ≤ day 3^b	1.03 (4013/3900)
	> Day 3^c	1.22 (1030/846)	[23]
		1.28 (1088/852)	[24]
	Total: > day 3^c	1.25 (2118/1698)
ICSI	≤ Day 3^b	0.94 (3047/3236)	[23]
		0.95 (2414/2542)	[24]
	Total: ≤ day 3^b	0.95 (5461/5778)
	> Day 3^c	0.98 (1542/1566)	[23]
		1.10 (1289/1167)	[24]
	Total: > day 3^c	1.04 (2831/2733)

^aLarge-sample surveys using United States [23] and Australia and New Zealand [24] assisted reproductive databases.
^bCleavage-stage transfer.
^cBlastocyst-stage transfer.

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