IVF
Invitro Fertilization
What is IVF, and how is it performed?
In vitro fertilization (IVF) was first successfully performed in Oldham, England, in 1978, resulting in the birth of Louise Brown. Since then, more than 1 million children have been born using IVF. The introduction of this technique completely changed and greatly improved-our ability to treat even the most difficult cases of infertility, many of which were previously untreatable. Although it is clearly not a '' cure-all '' for infertility, IVF has revolutionized our approach to, and understanding of, the disease called infertility.
IVF literally means '' the fertilization of eggs with sperm in the laboratory.'' An IVF cycle consists of several discrete phases, as detailed in the sections that follow.
PHASE 1 : OVARIAN STIMULATION
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A woman's ovaries contain thousands of fluid-filled sacs called follicles. Inside each follicle is an egg (or ovum). In a normal reproductive cycle, only a single follicle (and egg) reaches maturity. Although Louise Brown (the world's first IVF baby) was produced in a natural cycle from a single follicle, this form
Of IVF is less efficient because it often leads to cancelled cycles as a result of premature ovulation prior to the egg collection or the failure to retrieve the single egg that is produced.
The introduction of injectable gonadotropin drugs enabled physicians to increase the efficiency of IVF through the production of multiple mature follicles. Two forms of these medication are used : (1) drugs containing equal parts of the pituitary hormones follicle stimulating hormone (FSH) or luteinizing hormone (LH) [ Menopur ] or (2) drugs containing only FSH (Bravelle, Gonal-F, Follistim). Both kinds of medications induce the growth of multiple ovarian to them carefully with ultrasound and blood hormone testing.
Estrogen is produced within each of the developing follicles and induces the growth of the lining of the uterus (endome-trium).
Unfortunately, the rise in estrogen can also induce the pituitary gland to prematurely trigger ovulation, resulting in the cancellation of an IVF cycle. Two other classes of drugs are used to reduce the chance of this problem occurring during IVF stimulation: (1) GnRH agonists (such as Lupron and Synarel) and (2) GnRH antagonists (such as Centrotide and Antsgon). Lupron (or Synarel) is usually started 1 week prior to the women's anticipated next menstrual cycle. Given that a patient may have spontaneously conceived during this cycle, all women beginning Lupron are recommended to use a barrier from of contraception.
Approximately 1 week after starting Lupron, the woman should experience a normal menstrual period. An ultrasound exam is performed at the start of this menstrual cycle to examine the ovaries and measure any exiting cysts. In some cases, empty follicles from a previous cycle will persist and may influence the response to FSH. If the baseline ultrasound and blood tests are normal, then the patient receives instructions that afternoon as to when and what dose of medication she should take and when she should report back to the office for repeat ultrasound and blood tests.
Patients remain on Lupron to prevent the premature release of the eggs until the end of the stimulation phase. During a typical treatment cycle, they take daily injection for 9 to 12 days before the follicles reach maturity based on their ultrasound results and blood hormone levels. One the follicles reach a 20 to 24 mm diameter, the woman receives a final injection of human chorionic gonadotropin (HCG; Pregnyl, Profasi) at a precise time. This hormone serves as a trigger to incite the final maturation and release of the egg (ovulation). Ovulation typically occurs about 40 hours after this shot, so the egg collection procedure is scheduled for 34-36 hours after the HCG injection.
Cycles using GnRH antagonists are somewhat different. GnRH antagonists are started several days following the start of ovarian stimulation with gonadotropins. Most clinics add the GnRH antagonists once the largest follicle reaches a diameter of 14 mm. this medication effectively prevents the release of LH from the pituitary within hours of administration. Although many clinics have used GnRH antagonists successfully as part of their IVF stimulation protocols, some studies have demonstrated a trend towards decreased implantation rates in IVF cycles using this class of medications.
Phase2: oocyte retrieval
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Many physicians perform IVF as an office-based procedure whereas others utilize a free-standing surgery center.
Some programs are located within hospital. There are advantages and disadvantages to each of these. We prefer to perform the egg collection within our office, as the location and staff are familiar to the patient under going the IVF process. We also find that the location of the IVF lab. Within the office encourages continuous communication between patient, physician, and embryology staff .however, clearly many successful programs utilize a surgery centers or a hospital.
The use of a hospital setting may allow patients with significant medical conditions (cardiac disease, severe pulmonary disease) to undergo IVF, whereas such patients would be considered an anesthesia risk in the office setting.
Although many patients are nervous about the oocyte retrieval, in fact the vast majority of woman fined it to be less uncomfortable than some of the screening tests leading up to IVF .the egg collection is performed under light conscious intravenous sedition using a vaginal ultrasound probe with special needle guide adapter. The needle pass through the side of the vaginal into the ovary, and the follicles are easily aspirated. The fluid containing the eggs is then inspected by the embryologist using a microscope. Both the eggs and the sperm are then placed together in small plastic dishes containing media and incubated for the next 3 to 5 days. If there is significant male factor, then ICSI is performed several hours after the egg collection.
Phase 3: Embryo Culture
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On the day following the egg collection, patient learn how many eggs were fertilized .remember that also your re measures all of the follicles during stimulation, mature eggs are usually found only in follicles with diameters of more than 17mm.in general,
About 70% of the mature eggs will fertilize; unfortunately some attrition occurs at each point in an IVF cycle so the total number of healthy embryos is often mush less than the original number of follicles or eggs.
Three days after the egg collection procedure, the embryos selected for embryos transfer will be identified. If the couple is planning a blastocyst transfer, this step occurs on day 5 or 6 usually your RE will review the quality of the embryos with the embryologist and then discuss with you is or her recommendations regarding the number of embryos to transfer.
Embryos that are not selected foe transfer may still be of excellent quality, so they may be candidates for cryopreservation with liquid nitrogen. These frozen embryos can then be replaced into the uterus during a future cycle eliminating the need for the woman to undergo the entire IVF process of ovarian stimulation and egg collection.
There is little benefit to freezing poor quality embryos, however, because there are unlikely to result in at pregnancy and may not even survive the thawing process.
Phase 4: Embryo Transfer
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Embryo transfer is one of the most critical aspect of an IVF cycle. During this phase the embryos are transferred in a procedure similar to an IUI. At our office, we performed our embryos transfer under abdominal ultrasound guidance to ensure the accurate placement of the embryos into uterus. On the day of embryo transfer, patients are asked to drink 48 ounces of water and keep a full bladder to enable us to visualize the transfer of the embryos.
Phase 5: Post transfer and pregnancy
During the two weeks after the embryo transfer, patients take supplemental progesterone (shots and suppositories). If a patient's estrogen level drops significantly during the to weeks following embryo transfer, the physician may at supplemental estrogen as well.
Two weeks after the transfer, the woman typically undergoes a blood pregnancy test. Once a pregnancy test is positive, the physician may repeat the test every two days until the woman's beta HCG level is high enough to visualize the pregnancy sac on trans vaginal ultrasound (the beta HCG level should be more than 2000 iu around 3 to 4 weeks following embryo transfer).a follow up ultrasound is then performed to confirm fetal cardiac activity. At this point, patients are transferred to there obstetrician/gynecologist for parental care.
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