Should a single blastocyst transfer policy be a clinical decision or should it depend on the embryological evaluation on day 3?

Table 6 Summary and projected pregnancy rate compensating for the double counting of pregnancies in case a subject has more than one pregnancy

	eSET with elective day 5 transfer	eSET with transfer day 3 or 5		Statistical significance
No. of fresh cycles	341	249
No. of thawed cycles	188	143
Subjects with fresh or thawed clinical pregnancy	147	100
Subjects with fresh or thawed ongoing pregnancy	142	91
Number of embryos unthawed¹	38	98
Clinical pregnancy rate thawed embryos	26/286 (9.09)	21/229 (9.17)		NS
Ongoing pregnancy rate thawed embryos	24/286 (8.39)	18/229 (7.86)		NS
Projected number subjects with clinical pregnancy²	3.45	9.68 (1.24+8.44)
Projected number subjects with a ongoing pregnancy²	3.19	8.20 (1.24+6.96)
Projected cumulative clinical pregnancy rate³	150.45/341 (44.12)	109.68/249 (44.04)		NS
Projected cumulative ongoing pregnancy rate³	145.19/341 (42.58)	99.20/249 (39.84)		NS
		Day 3	Day 5
No. of fresh cycles		135	102
No. of thawed cycles		41	102
Subjects with fresh or thawed clinical pregnancy		43	57
Subjects with fresh or thawed ongoing pregnancy		40	51
Number of embryos unthawed²		26	72
Clinical pregnancy rate thawed embryos		4/84 (4.76)	17/145 (11.72)	NS
Ongoing pregnancy rate thawed embryos		4/84 (4.76)	14/145 (9.66)	NS
Projected number subjects with clinical pregnancy		1.24	8.44
Projected number subjects with a ongoing pregnancy		1.24	6.96

¹ Number of embryos unthawed for subjects with no fresh or thawed pregnancy
² Projected from the unthawed material among subjects without a fresh or thawed pregnancy, assuming that the pregnancy rate will be the same as for the already thawed material
³ Fresh pregnancies, thawed pregnancies and projected number of pregnancies/number of subjects

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