FET - to down regulate or not down regulate?

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Posts: 8
Joined: Fri Aug 24, 2018 4:32 am

FET - to down regulate or not down regulate?

Post by Mtntn »


Firstly, thank you again for all the time you give to answer questions on this board.

I have written before while I was going through egg retrieval/PGS and you were very kind to reply. I was very fortunate to get six PGS normal embryos with my second egg retrieval at 40 yrs of age with PCOS.

In December I did my first FET with a PGS normal embryo, which unfortunately was not successful. It turned out to be a chemical pregnancy. I'm now planning for my second.

I did not have many investigations before my treatment, so I am going to get a saline sonogram before this second FET and also ask my RE about blood clotting/immune problems. I am also going to speak to my RE about an ERA, however, I was wondering if an ERA is useful considering there was some implantation, albeit brief?

I am also deciding on FET protocols. I will have to do a medicated FET as my clinic does not do transfers on the weekends, so therefore a natural cycle would be too risky timing wise. I was wondering however if there is a difference in success rates for medicated cycles, with down-regulation, versus no downregulation? I am very hesitant to do another down-regulated FET. For my first one, I ended up doing down-regulation for 6 weeks. I have read one paper that said prolonged estrogen exposure in a non downregulated cycle can have a negative impact but as long as estrogen exposure is less than or equal to 20 days, then there is no significant difference. I am eager to do the FET as soon as I can, however also want to choose the path with the most chance of success. It would be great to hear what you think re: DR v's no DR before a FET.

Thank you all for your thoughts!
Dr. Rosen
Posts: 4
Joined: Mon Oct 29, 2018 11:45 am

Re: FET - to down regulate or not down regulate?

Post by Dr. Rosen »

You ask a lot of questions and I will try my best to answer them all.

1. Statistically there should be no difference in pregnancy rate in a medicated versus non-medicated cycle. Likewise, I do not believe down regulation should have any effect.

2. The best data I think on the number of days of estrogen priming prior to starting progesterone in a medicated embryo transfer cycle is from Spain and it looks at egg donor data. They state there’s no difference in pregnancy rates if the person is on estrogen for between 14 to 28 days.

3. The purpose of doing in ERA is to see if the uterine lining is receptive during a certain type of stimulation. It looks at the dose and duration of progesterone prior to the embryo transfer, specifically. In order to take the information from your last cycle, i.e., the one in which you had implantation, you would have to do the same cycle with regard to dose and duration of progesterone. If you want to do a completely different type of stimulation, i.e., with different types or doses of both estrogen and progesterone, then an ERA might be warranted.

Dr. Rosen
Reprodutive Partners Medical Group, Inc.
Dr. Gregory Rosen
Reproductive Partners Medical Group, Inc.
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