Estrogen priming is a protocol used during in vitro fertilization (IVF) to facilitate a more gradual and coordinated growth of follicles in the ovary in women with diminished ovarian reserve (DOR). Estrogen is administered during the luteal phase of the previous menstrual cycle to "prime" the FSH receptors which enhances the response to FSH.
This helps to improve the outcome of the IVF cycle in patients who respond poorly to traditional IVF protocols. Estrogen priming also allows the patient and clinicians to schedule the ovarian stimulation cycle and the timing of egg retrieval.
FertilitySmarts explains Estrogen Priming
One of the most important steps in the in vitro fertilization is stimulating the ovaries to develop multiple eggs. Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) are used to stimulate the ovaries to recruit and develop more than one follicle. A gonadotropin-releasing antagonist hormone (GnRH-ant) is used to stop the ovaries from releasing the matured eggs and allows time for additional maturation until eggs are retrieved for fertilization.
But not all patients respond equally to ovarian stimulation using these hormones. Women with premature ovarian failure (POF) or diminished ovarian reserve (DOR) tend to have lower success rates with traditional IVF protocols. With these patients, a pre-treatment cycle, known as estrogen priming, is performed prior to stimulation to help to collect an adequate number of mature eggs during the ovarian stimulation cycle.
There are several methods of pre-treatment that involves using either a combined oral contraceptive pill, progestogen or estrogen. Pre-treatment is known to improve the response of the ovary to the stimulation cycle and also reduces the risk of ovarian cyst formation.