Endometrial Thickness & Implantation: Understanding Your Cycle with Letrozole

Question
QUESTION: Hello,

I was previously given clomid, but characteristics of my period was concerning for possible thinning of endometrium (plus my CM was scant and thick), so I was switched to letrozole this cycle. I am undergoing therapeutic donor insemination. Also, because, although I DO ovulate, I have yet to have a clearly   OPK, this cycle I will self-administer a trigger shot.  

Yesterday, on CD 12, I had a mid-cycle u/s. I had 20mm, 19mm, and 16mm follicles. But, my endometrium was only 6.8mm. I usually ovulate on CD 15. My RE recommended not giving trigger shot yesterday because of my endometrium, and rather giving it tonight, (around 30 hours after the ultrasound), for planned IUI Monday AM.

If my thickness was 6.8mm 3pm friday, how thick might it be by the time I give myself the trigger shot, and should I be worried that it will not be thick enough for implantation?

thank you,
Bethany

ANSWER: Hello Bethany,

Thank you for your question.  Where are you writing from?  I always curious.

You didn't mention if your RE placed you on any supplemental estrogen, which might help, but if your lining is 6.8, there is a chance that it will increase in time.  It just needs to get to 9 mms. Implantation will not occur for 7 days after ovulation.

Hope this answers your question.

Sincerely,

Edward J. Ramirez, M.D.
Executive Medical Director
The Fertility and Gynecology Center
Monterey Bay IVF Program
www.montereybayivf.com

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

QUESTION: Hi Dr. Ramirez,

I'm writing from Iowa City, IA.  (I'm an ENT resident at University of Iowa)

I am not on any supplemental estrogen. Is there anything that I can do to help the situation myself?

Also, is there a chance that the endometrial lining WON'T get thicker?

Is there an average daily rate of endometrial growth?

And, does the endometrium stop thickening after the hCG shot?

thanks againn,
Bethany

Answer
Hello Bethany,

My younger brother is an ENT physician and also did a fellowship in facial plastic surgery.

Yes.  Go to the OB/GYN clinic and see if they have any samples of Vaginfem vaginal estrogen tabs 2 vaginally per day or Divigel 0.1% - 1mg applied to vulva qd or Climara patch 0.1mg two patches per week or any of the other patches 0.1 mg two patches every three days.  I would start ASAP.

There is a chance that the endometrium won't get thicker.  That is a side effect of the Clomid.  HCG does not stop estrogen production right away but it will drop off.  The problem is, the HCG will start the conversion of the endometrium from the proliferative phase to the luteal phase in preparation for implantation.  Adding estrogen will still help, however, and we do this automatically in IVF cycles for that purpose.  Your RE should know all this so you should discuss it with him or her as well.

Sincerely,

Edward J. Ramirez, M.D.
Executive Medical Director
The Fertility and Gynecology Center
Monterey Bay IVF Program
www.montereybayivf.com