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Infertility/Fertility/Follicles grouwth tracking and HCG injection


QUESTION: hi, I am 35 years old just started infertility treatment in Sep 2013.
I had clomid 50mg on cd 3-7 and had a blood test on cd 9 & 10. they said there was a nice rise in oestrogen level (don't know how much) and did u/s on cd 10 @ 0900hrs to find 1 follicle 15mm and multiple small ones (24 in total). I was instructed to have hcg 5000iu on cd 11 @ 1800hrs and intercourse on the same day and next day. I did so. this is cd 15 there has been no rise in basal temperature. I am wondering if I did not ovulate at all cause it was too early to give hcg.  

from internet search it says hcg to be given when the follicle is at least 18mm. they did not do further u/s tracking so I am not sure how big the follicle was at the time hcg given.

I appreciate if you can give me some insite of this case

ANSWER: Hello Natsumi from Australia,

The method used for your Clomid ovulation induction is not the correct method but one that is used by many Ob/Gyn doctors who don't know better or don't have the appropriate knowledge and experience.

First, 50 mg is the lowest possible dose.  Clomid can be given in dosages up to 250 mg and the goal is usually to try to have 2-3 follicles that are ovulatory sized (18-24mms).

Second, a blood test on CD#9 and 10 is probably not necessary with Clomid.  It is used with injectables to make sure you are not overstimulating but that is not an issue with Clomid because it is a low strength medication.

Third, some means of ovulation detection needs to be done.  General Ob/Gyn's tend to use an ovulation predictor kit (OPK) or LH surge kit, but real infertility specialists use the ultrasound because it gives more information.  It provides information such as how many follicles you are growing, what are their sizes and when are they ready to trigger for ovulation to help you time intercourse.  If you only have one follicle, that is the number you would naturally make so that means the Clomid did nothing in this cycle i.e. the 50 mg was an inadequate dose.

Finally, my preference is for the follicle to be 20-22 mms at the time of HCG trigger.  It is possible that your follicle was too small to trigger ovulation so that ovulation did not occur.  I think your doctors timed it completely wrong.  Since the follicle was 15 mmg on CD#10 you should have waited 3 more days to trigger.  In general, the follicle grows 2 mms per day.

Good Luck,

Dr. Edward J. Ramirez, M.D., FACOG
Executive Medical Director
The Fertility and Gynecology Center
Monterey Bay IVF Program

Monterey, California, U.S.A.

for additional information check out my blog at check me out on twitter with me at @montereybayivf and facebook @montereybayivf

---------- FOLLOW-UP ----------

QUESTION: Hello, Dr. Edward,

Thanks for your answer. It was really helpful to give more incite of what's going on. And may I ask further about ovulation trigger?

I'm now on cd 22 and having pregnyl 1500iu every 4th day. My blood test on cd 18 showed progesterone 10 and oestrogen 160, and my basal temperature rose by about 0.7C so far. They said I ovulated and their criteria of the size of follicles to trigger is 16-20mm.  

Having said that your preference is 20-22 mm to trigger ovulation, mine would've been obviously smaller than that. Although it would've been fit in their criteria, I agree it's too early to trigger. What happens if ovulate when it is smaller than 18mm?

Kind regards,

Natsumi Yagi


If the trigger is given too early, the follicle, and the egg within, start to undergo changes and so ovulation does not occur.  In that case, pregnancy would not occur either.

You mention that your doctors said that you ovulated, but how do they know?  Were they using progesterone levels and temperature.  The progesterone levels would show an increase because you are taking pregnyl for luteal phase support and that would increase the temperature as well.  This invalidates those two methods for detecting ovulation.

Ovulation can certainly occur at 16 mms, as has been shown in older studies, but not often.  A protocol using a size of 16 mms is way too low and outdated.  The smallest size should be 18 mms.  If ovulation does occur from a smaller follicle, there is no difference than if it occurred at 20 mms.  Ovulation will not occur unless the egg reaches maturity so as long as that has happened, then ovulation will occur.

Good Luck,

Dr. Edward J. Ramirez, M.D., FACOG
Executive Medical Director
The Fertility and Gynecology Center
Monterey Bay IVF Program

Monterey, California, U.S.A.

for additional information check out my blog at check me out on twitter with me at @montereybayivf and facebook @montereybayivf  


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Edward Joseph Ramirez, MD, FACOG


I am a specialist in infertility and advanced gynecological care. I can answer questions about infertility, gynecology related ills, menopause...virtually anything that affects women's health. PLEASE tell me where you are writing from as I am always interested.


I have been practicing as an Ob/Gyn and Infertility Specialist for over 23 years. Gynecology, advanced laparoscopic surgery, basic infertility, IUI's, IVF, reproductive surgery, and ovulation induction are all areas of my expertise. I am Board Certified. I have been doing In Vitro Fertilization in my clinic for 19 years.

American College of OB/GYN, American Board of Obstetrics and Gynecology, American Society of Reproductive Medicine, California Medical Association, American Association of Gynecologic Laparoscopists, Fellow of The American College of Obstetricians & Gynecologists

American Journal of Obstetrics and Gynecology, Wall Street Journal, Monterey Herald, SERMO, Women's Health and Fertility Blog

Medical Degree from Stanford University, Residency at Tripler Army Medical Center, Reproductive Training at Pacific Fertility Center, San Francisco

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