Progesterone levels for FET

Discussion in 'Assisted Conception' started by arianne, Sep 13, 2019.

  1. arianne

    arianne Well-Known Member

    Nov 5, 2010
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    I have a question about progesterone i dont undestand.

    What is the ideal number for FET? and why it needs to be low?
    My clinic says mine is too high to move forward with the FET. It's 14.3 nmol/L
    So they want to let my period come, put me in birth control pills and lupron first before the estradiol (which i took for the last 10 days)

    I am wondering why is the need for suppressing your ovulation for FET? since that is the natural women's cycle and embryos do implant at the end of that natural cycle.

    It makes sense to take estradiol as it is for your linning, but why does it need to be combined with suppressing ovulation. Women get pregnant with an ovulating cycle as opposed with a non ovulating one, the body would stop ovulating and progesterone levels would go where they need to be for the body to have an embryo implanted. So i dont undestand the logic behind it

    I would love to hear if your doctor had you on suppression ov medication for your FET

    Thank you so much in advance!
  2. MKaykes

    MKaykes Well-Known Member

    Aug 9, 2015
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    I never asked, but I assumed inhibiting ovulation was to allow the pregnancy to occur from the FET and not a natural pregnancy. But I have heard of people who didn't suppress ovulation from having a naturally occurring pregnancy with an IVF pregnancy, resulting in twins. They would risk losing a natural pregnancy by the procedure.
  3. Wish2BMom

    Wish2BMom Well-Known Member

    Jan 17, 2014
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    I thought it all had to do with controlling the timing of everything - if you ovulate before they are ready to transfer, then you'll start producing progesterone before the embryos get in there. If they suppress what your body normally does, then they have control over the growing the lining and are able to monitor the exact time they should transfer the embie which would be when you would normally ovulate. Then you start with the progesterone, as your body normally would, but maybe at different levels (like my TWW would only be 9-10 days normally, so I needed more progesterone to let the embies settle in and have a chance of sticking around). I think it's all about control but I also agree with MKaykes - that would be an additional reason.
  4. jsquared

    jsquared Well-Known Member

    Nov 4, 2013
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    Once you start producing progesterone, your lining stops growing and the uterine environment changes. That's an oversimplification, but it's how I always understood it to work. They want the lining as thick and receptive as possible before the progesterone phase.

    Also, for FET, the progesterone levels need to match the age of the embryo. You can't put in a 5 day blast on 2 days of progesterone, or 8 days, etc. There are some exceptions to this but usually within 1-2 days (ERA and/or good guessing by your RE can pinpoint most receptive window).

    So for FET success you need:
    -Lining at good thickness/consistency
    -the right levels of progesterone
    -the right window of time for transfer
    Every element depends on the other. And of course, the right blast.

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