Table 2.

Summary of data published about factor that may affect 3D-ultrasound assessment of menstrual cycle

Author	n	Primary Outcome	3D Method	Study Design	Findings
Ng (52)	67	Endometrial and subendometrial vascularity in spontaneous and stimulated cycles	VOCAL	Cross-sectional: oocyte retrieval day in stimulated cycles and LH surge day in spontaneous cycles	Endometrial and subendometrial vascularity was significantly lower in stimulated cycles as compared with spontaneous cycles
Ng (53)	645	Endometrial and subendometrial vascularity in spontaneous and stimulated cycles	VOCAL	Cross-sectional: oocyte retrieval day in stimulated cycles and LH surge day in spontaneous cycles	Uterine PI and RI were weakly correlated with endometrial and subendometrial VI/FI/VFI, both in spontaneous and stimulated cycles.
Chan (54)	60	Endometrial volume, and endometrial and subendometrial vascularity	VOCAL	Cross-sectional: oocyte retrieval day	Endometrial and subendometrial VI/FI/VFI are not affected by different r-hCG dosage
Ng (55)	32	Endometrial and subendometrial vascularity in stimulated cycles	VOCAL	Longitudinal hCG +2, hCG +4, hCG +7	Changes in endometrial and subendometrial VI/FI/VFI are different in excessive responders as compared with moderate responders.
Raine-Fenning (56)	48	Endometrial and subendometrial vascularity in fertile and unexplained subfertile women	VOCAL	Longitudinal at 2 days interval in follicular phase and 4 days interval in luteal phase	Endometrial and subendometrial VI/FI/VFI were significantly lower in women with unexplained subfertility
Ng (57–59)	645	Endometrial and subendometrial vascularity	VOCAL	Cross-sectional Oocyte retrieval	Endometrial and subendometrial VI/FI/VFI are not affected by women's age, smoking, type and cause of infertility, presence of hydrosalpinx or uterine fibroids