Brief Answer:
Possibility of twins is high.Serial Ultrasonography is needed to confirm.

Detailed Answer:
Hello, Madam.

I understand your concern.

The process of dominance begins late when suddenly a certain underdog follicle starts growing faster and suppresses others to become dominant".So it is not always the largest follicle that ruptures.

Let me explain certain points to you.This will help you to understand better.

During Day 5-7 of the menstrual cycle, a process of 'dominance' begins, when a certain follicle of 10 mm size takes the control and becomes dominant. This also suppresses the growth of the rest of the selected follicles, and in a way is destined to ovulate. This follicle starts growing at a rate of 2-3 mm a day and reaches 17-27 mm size just prior to ovulation.

Transvaginal ultrasound is preferred and usually mandatory modality for monitoring follicles. Ultrasound monitoring may begin on day 3 of the cycle.

As the study progresses on day 7, we should start guessing the ovulatory dominant follicle i.e. dominant follicle which is destined to ovulate. Basically, there are three varieties of eligible follicles:

1.Atretic dominant follicle: This follicle is usually largest follicle on day 3, but it is not destined to ovulate. It has an irregular shape, rough edges, and may be little echogenic.

2.Ovulatory dominant follicle: This follicle is typically round, with smooth borders, and usually hypoechoic.

3.Anovulatory-luteinizing dominant follicle: This dominant follicle grows at a good pace but fails to ovulate, and later becomes a cyst or luteinizes. These are also round and smooth, however anechoic.

This subtle recognition of echogenicity difference between hypoechoic and anechoic follicle can help determine whether a follicle is growing to ovulate.

Once the follicle reaches 16 mm size, a daily monitoring of follicle is recommended.Next step is documentation of ovulation. Ovulation is sonographically determined by various sonographic signs.

The possibility of twins can be accurately predicted after the Ovulation.

The HCG Inj cause ovulation of the egg from the follicle 36-40 hours after the injection.

Ideally the best time to have coitus(sex) will be on the day of the hCG injection and repeat it next day as the egg will get sperms from both the acts of intercourse.

Chances of a twin pregnancy are high in your case.Mature follicle should measure at least 18mm.Since you have 2 follicles in size excess of 20 mm in the right ovary
the possibility of twin gestation is high.But it can be proved only after the fertilization detected on serial Ultrasound.

The endometrial thickness seems to be in favor for the nidus.

Post your further queries if any.
Thank you.

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