More studies are needed.įor intramuscular P (PIO), 50 mg a day is common. 2021 you can read my summary of that article here). Some studies have suggested there is no difference, while a recent RCT found that intramuscular injections alone, or in combination with vaginal progesterone, is superior to vaginal progesterone alone ( Devine et al. endometrin) or progesterone in oil (PIO) intramuscular shots. There are a number of ways to do it, but most commonly is by vaginal suppository (ie. Since there is no ovulation (and therefore no corpus luteum!) in a medicated FET cycle, there is no progesterone secretion, so it needs to be administered exogenously (from outside the body). Once the endometrium is 7 mm or greater, progesterone can start to be administered. In some cases, this E2 timing can be shorter (5-7 days) or longer (28 or as high as 36 days). 2010).Į2 is administered for around 2 weeks and then an ultrasound is performed to check for endometrial thickness (and to make sure a follicle isn’t developing!). There doesn’t seem to be any difference in reproductive outcomes ( Glujovsky et al. (2016) compared these two methods and found no difference in live birth rates.Į2 can be administered by oral, vaginal, or transdermal routes, with oral E2 being the most common. 2 mg/day for days 1-7, then 4 mg/day for days 8-12, then 6 mg/day from day 13 to transfer). 6 mg daily) or can be increased over time (ie. In the past, a GnRH agonist would be used to prevent the LH surge, but estradiol alone is able to suppress this.Į2 can be administered either as a fixed dose (ie. Estradiol also prevents further follicles from growing because it blocks GnRH and prevents FSH/ LH from being produced. In a medicated FET protocol, the endometrium is first prepared using estradiol (E2) which causes the cells of the endometrium to proliferate. These need to be administered exogenously (from outside the body)! This continues until about 10 weeks of pregnancy, at which point the placenta starts to produce progesterone (taking over the job of the corpus luteum) in the so-called luteo-placenta shift.īirth control is often taken before starting estradiol administration to better manage the timing of the medicated FET cycle. In a medicated FET, complete hormone replacement is needed because there is no follicle here to produce estradiol, and therefore there’s no corpus luteum to produce progesterone. I’m also including the natural cycle hormone levels to show how a medicated FET protocol mimics a natural cycle. The below diagram is showing cycle days 1-21 (which can vary) and a fresh ET as a reference (which isn’t showing progesterone administration for simplicity). Check here for the full glossary (please excuse the repeated terms!). Terms are highlighted every 3rd time to avoid repetition. Reminder: I have an integrated glossary in the text (terms are underlined with a dotted black line, and when you tap on it a window will pop up with the definition). Sometimes you might hear of “ luteal phase support”, and this refers to administering progesterone to mimic the luteal phase as described above. This is called “endometrial preparation”. In frozen embryo transfers, estrogen and progesterone may need to be administered to prepare the endometrium artificially. This causes progesterone levels to drop and triggers menstruation at which point the endometrium is shed and the cycle starts over. If there’s no implantation, then there’s no hCG produced and the corpus luteum eventually degrades. The embryo implants during this phase and begins secreting hCG that signals to the corpus luteum to keep producing progesterone (this continues for about 10 weeks). This maintains the thickened endometrium and transforms its cells and architecture so it can accept an embryo for implantation. The empty follicle is now called the corpus luteum and begins secreting progesterone (P4), so P4 levels begin to rise. The leading follicle ovulates and the egg is released into a fallopian tube.įrom CD15 to CD28 the endometrium is now in the secretory phase (aka the luteal phase). Menstruation and the proliferative phase both occur while the follicle is developing, so CD1-CD14 is can be called the follicular phase.Į2 eventually peaks and this causes an LH surge to trigger ovulation. During this phase, the cells of the endometrium proliferate and thicken. These developing follicles begin to produce estrogen, or more specifically estradiol (E2), which causes the endometrium to enter the proliferative phase (CD6 to CD14). LH/ FSH causes follicles in the ovaries to develop. During this period, GnRH acts on the pituitary gland to secrete LH/FSH. Source: Isometrik, CC BY-SA 3.0, via Wikimedia CommonsĬycle day 1 (CD1) to about day 5 is menstruation.
0 Comments
Leave a Reply. |