Role of USG in IUI
Ultrasound monitoring in IUI cycle
- Ultrasound monitoring through trans vaginal sonography is done starting from day 7 after administration of ovulation induction agent or day 9 of natural cycle.
- Dominant follicle grows at rate of 1-2 mm/day.
- Ovulation trigger is administered when follicle reaches maturity i.e. > 18 mm mean diameter.
The potential signs of impending ovulation are
- Presence of a dominant follicle (usually more than 16 to 18 mm)
- Peri vascular blood flow encompassing 3/4th of follicular circumference. Perifollicular blood flow PSV > 10 cm/sec.
- Anechoic area, double contour, around the follicle (possible ovulation within 24 hrs)
- Separation and folding of the follicle lining (ovulation within 6 to 10 hrs)
- Thickened proliferative endometrium
How USG confirms that there is ovulation?
Sonography does appear to be very reliable in confirming ovulation once ovulation has occurred. Disappearance of the follicle is noted in 91 percent of cases after ovulation and a decrease in follicle size occurs in another 9 percent. Other signs suggesting that ovulation has occurred are the appearance of cul-de-sac fluid, particularly when it was not present in a previous scan, or the development of intrafollicular echoes suggesting the formation of a hemorrhagic corpus luteum.