IVF (in vitro fertilization) is a process in which eggs, retrieved from a woman’s ovaries, are fertilized in the laboratory with sperm provided by her husband, partner or a donor. When fertilization is successful, the resulting embryos are transferred into the woman’s uterus.
1. Follicular stimulation and monitoring
Fertility specialist physicians (Reproductive Endocrinologists) prescribe medications or hormones in order to increase the likelihood of collecting multiple eggs and to control the timing of a patient’s menstrual cycle. The patient and her partner may administer these medications on a daily basis within the privacy of their home. RSC fertility center staff then monitor the patient’s progress by evaluating the number of ovarian follicles in development through vaginal ultrasound and serial blood samples taken at a Reproductive Science Center fertility clinic in Massachusetts, New Hampshire or Rhode Island or one of our recommended monitoring sites. A follicle is a sac of fluid in the ovary that may contain an egg (oocyte). Your RSC New England fertility doctor determines the number and frequency of these tests.
Just prior to egg retrieval, a patient takes an additional injectable medication to complete the maturation of the eggs. The retrieval is scheduled only if there are an adequate number of follicles ready.
2. Oocyte (Egg) Retrieval
Each egg retrieval takes place under intravenous conscious sedation at RSC in Lexington, MA. Licensed anesthesiologists monitor patients. While sedated, the RSC fertility doctor inserts a probe through the vagina under ultrasound guidance into the ovaries to aspirate (withdraw) follicular fluid from each follicle. Not all follicles necessarily contain eggs. Following the retrieval, the patient rests in the recovery room under the care of the RSC PACU (post anesthesia care unit) nurses and medical assistants to allow effects of the anesthesia to subside.
3. Fertilization and Incubation
Once eggs have been retrieved, the male partner’s sperm is collected and eggs and sperm are brought together for fertilization. The embryologist may choose from a number of techniques including the microdrop method or a microinsemination technique called intracytoplasmic sperm injection known as ICSI (“ik-see”). In ICSI, an embryologist injects a single sperm directly into an egg under a microscope with a tiny needle. Fertilized eggs are then incubated in the embryology laboratory for two to five days prior to embryo transfer.
4. Embryo Transfer Procedure
If the embryos have developed normally after incubation, an RSC physician transfers a predetermined number of embryos through the cervix into the uterus via a small catheter (hollow tube). The patient and her physician determine the number of embryos for transfer based on individual circumstances such as age and medical history. No anesthesia is required for this procedure, although Valium is given for uterine relaxation.
In order to enhance the likelihood of conception, the physician prescribes hormonal therapy following embryo transfer. As in the natural reproduction process, a pregnancy may or may not result. If any excess embryos exist after the initial transfer, the patient may request evaluation for possible freezing and use for a subsequent treatment cycle.
Frozen Embryo Transfer (FET)
Unused embryos can be cryopreserved (frozen) in liquid nitrogen for possible thawing and later use. Embryos may be frozen anytime after the fertilization stage (pronuclear zygotes, which is one day after egg retrieval up to and including the blastocyst stage, which is 5 days after retrieval. Most commonly, embryos are frozen at either day three or day five. Your physician will discuss both options and a decision will be reached as to which is best suited for your particular case.
While pregnancy rates with frozen embryos are not quite as high as with fresh embryos, the success rates are still quite respectable and the preparation for a frozen embryo transfer is much simpler and less expensive compared with a fresh cycle attempt. Freezing only embryos that survive to the blastocyst stage maximizes the chance for success in a thaw cycle.
This information is provided for general education purposes and is not intended to take the place of a discussion with your physician. If you have questions about any aspect of your health, you are advised to speak with your physician.