TABLE 1.

Studies investigating the region-specific implantation frequency of blastocysts within the endometrial cavity

Study	Hertig 1956	Kawakami 1993	Minami 2003	Cavagna 2006
Design	Anatomic dissection of 211 hysterectomy specimens derived from women of known fertility; a subset of which were derived from women during the luteal phase with early pregnancies, some having already implanted	2-Dimensional Transvaginal Ultrasonography on fertility clinic patients during the follicular phase and prior to 6 weeks gestation dated by basal body temperature	3-Dimensional Transvaginal Ultrasonography on unselected women with gestational sacs measuring 3-6mm	3-Dimensional Transvaginal Ultrasonography performed 21-24 days after embryo transfer (ET) on women with singleton pregnancies having undergone ICSI and ultrasound-guided ET intentionally directed to the midpoint between the internal os and fundus
Sample size Conception	26 spontaneous	21 spontaneous	138 spontaneous	47 assisted
Fundus (midline)	100% in upper cavity: 58% ipsilateral to corpus luteum 4% midline 38% contralateral to corpus luteum	Upper versus middle cavity not specified: 81% ipsilateral to dominant follicle 14% midline 5% contralateral to dominant follicle	16%	34%
Left Cornu			39%	15%
Right Cornu			34%	17%
Anterior Body			9% middle cavity region	30% middle cavity region
Posterior Body
Lower uterine Segment			2%	4%