Thread: Frozen embryo Transfer

Fortunately, we do not have to stimulate a woman's ovaries in preparation for a frozen embryo transfer as the eggs have already been retrieved and in fact are fertilized and usually developed into a seemingly healthy embryo or else the embryos would not have been worth freezing.

There are two options. An ovulating woman may use her natural cycle and transfer the frozen thawed embryo on the corresponding day after ovulation, i.e. an embryo frozen on day 3 may be transferred approzimately 3 days after ovulation. This requires monitoring closely for ovulation. Unless you are very regular this can require several consecutive office visits to determine the precise day of ovulation.

The alternative is to build up the lining of the endometrium with estrogen which can be administered orally, vaginally, transdermally or intramuscularly. Some programs will give agonist or antagonist to prevent ovulation. Estrogen alone will usually suppress ovulation. Timing transfer then becomes a matter of reaching adequate endometrial thickness which is generally accepted to be about 8mm. We will schedule a thaw when a patient reaches 8mm endometrial thichkness and administed progesterone in addition to estrogen to correspond to what the ovary would have secreted on the day of ovulation. If we are transferring an embryo frozen on day 3 we typically will give the patient progesterone for 3 days prior to transferring the thawed embryo. We typically will monitor patients weekly to assess endometrial thickness and at the same time check that the patient is not spontaneously ovulating which would move up our transfer date as dictated in the natural cycle scenario.