1. CONTROLLED OVARIAN HYPERSTIMULATION (COH)
IVF success rates are dependent upon the number of the mature eggs and healthy embryos available for transfer. A patient undergoing IVF is given fertility drugs for two reasons: (1) to improve the growth and development of her ovarian follicles in order to produce as many healthy eggs as possible and (2) to control the timing of ovulation so that the eggs can be retrieved before ovulation, with as many of them being mature as possible. In cases where the patient has previously received fertility drugs, the subsequent treatment regime is largely based upon her most past response to such treatment. For a patient receiving gonadotropins for the first time, the dosage and regimen is determined by her follicle stimulating hormone (FSH), estradiol (E2) and anti-Mullerian hormone (AMH) concentrations, antral follicle count (AFC), medical history, body habitus and other variables as well.
In almost all cases, the patient begins her treatment by starting birth control/oral contraceptive pills (BCP/OCP) before initiating daily injections of FSH (Follistim or Gonal F) and/or FSH/LH (Menopur). Typically, the injections are started the day after stopping BCPs and continued for 6-10 days or until follicles (eggs) become mature. During this time, patient undergoes 2-4 ultrasound examinations and blood testing of her estrogen levels. When the follicles are between 14-16mm as determined by an ultrasound, the group of medications called GnRH antagonists (Ganirelix or Cetrotide) are started to prevent premature ovulation.
Once the eggs are mature based on size, the egg retrieval procedure is then scheduled. This involves taking the “ovulation trigger” drug called human chorionic gonadotropin (HSG) also known as Novarel or Pregnyl brand names. 34-36 hours after the injection of HCG, eggs are aspirated from the ovaries vaginally. An antibiotic called doxycycline is commonly prescribed to prevent an infection around the time of an egg retrieval.
2. THE EGG RETRIEVAL
Egg retrieval involves a procedure where under direct vaginal ultrasound guidance, a needle is passed along the side of a vaginal ultrasound probe through the top of the vagina into the ovaries and then the follicles (small fluid filled spaces that each contain an egg). The follicular fluid and the egg are aspirated and collected in a sterile tube, which is handed directly to the embryologist for evaluation and fertilization. The procedure itself is painless because it is done under anesthesia, however patients commonly experience some postoperative abdominal discomfort or cramping. Anesthesia used for egg retrieval is unconscious intravenous (IV) sedation preventing patients from feeling the pain and discomfort during the procedure. This type of anesthesia does not require intubation (placement of tube in the mouth/throat)like complete general anesthesia, but rather involves a very deep sleep for 15- 20 minutes. Postoperatively all patients are given detailed instructions and are discharged from the recovery area.
3. SPERM PROCESSING
Sperm is usually obtained through masturbation from the male partner. In some cases, the sperm may need to be retrieved from the testicles under local or general anesthesia using the techniques called Testicular Sperm Extraction (TESE) or Percutaneus Epididymal Sperm Aspiration (PESA). TESE or PESA are procedures of choice in cases where there is blockage of the sperm ducts (as occurs following vasectomy or following severe injury or infection), or where the man is born without sperm ducts (congenital absence of the vas deferens). Sometimes, in cases of retrograde ejaculation, sperm can be collected from the man’s bladder. Infrequently, in men with spinal cord injuries, ejaculation is facilitated by electrical stimulation (electro-ejaculation). Donor sperm, obtained from a sperm bank can also be used when indicated.
Sperm must undergo biochemical and structural changes known as capacitation, before an egg can be fertilized. Capacitation (which under normal circumstances takes place in the patient’s reproductive tract) must be accomplished in the embryology laboratory prior to insemination of the eggs. Motile sperm are processed and used for fertilization.
“In vitro” fertilization means “fertilization in the laboratory” rather than inside the fallopian tubes. Aspirated ovarian follicles are examined in the embryology laboratory, the eggs are identified, extracted and are placed in a special culture medium. At that time there are two ways of fertilizing the eggs:
The first one is called the IVF-Insemination (Not IUI or Intrauterine Insemination) technique where approximately 25,000 -100,000 processed sperm are placed around each of the eggs. The eggs and sperm are allowed to incubate together in a carefully controlled environment. Approximately 16-24 hours later, the eggs are inspected microscopically for fertilization as evidenced by the presence of two nuclear bodies. These binuclear unicellular bodies are referred to as “pro-nuclear embryos”.
The second option is the intracytoplasmic sperm injection (ICSI) which has revolutionized especially the treatment of severe male infertility and other causes of infertility as well. The procedure involves the direct injection of a single sperm into each egg under direct microscopic vision. Using this technique, the best sperm can typically be identified under the microscope. The successful performance of ICSI requires a high level of technical expertise. When ICSI is employed, the IVF birth rate is very high in the presence of male infertility. In fact, even when the absence of sperm in the ejaculate requires that ICSI be performed on sperm obtained through TESE or PESA, the success rates are high as well.
The introduction of ICSI has made it possible to fertilize eggs with sperm derived from men with severe degrees of male infertility. The indications for ICSI have broadened dramatically, with the process now being used for a variety of indications other than male factor infertility. We also use ICSI to assist in the fertilization of eggs that are believed to have a hardened or thickened outer envelope called the zona pellucida. This is frequently found in the association with polycystic ovary syndrome (PCOS), endometriosis, unexplained infertility and in eggs derived from women of advanced reproductive age (age over 35). ICSI is also frequently recommended in cases of “unexplained infertility” and where there is a history of poor fertilization during one or more prior IVF attempts.
5. EMBRYO CULTURE AND PREIMPLANTATION GENETIC TESTING (PGT)
Once eggs are fertilized on day 1, the embryos are typically cultured for 3-6 days and observed for embryo development. At our laboratory, we culture embryos to the final stage called the blastocyst stage (Day 5 or 6 embryo stage), although they can be transferred into the uterus on the third day or frozen on the third day as well. Extended culture of the embryos allows some of the chromosomally/genetically abnormal embryos to be selected out while culturing them in the IVF laboratory. If an embryo stops developing in the culture system, it is almost always genetically or chromosomally abnormal. This does not mean that if the embryo develops to the final stage that it is normal either. Some of the abnormal embryos will still develop to the final stage and they can even implant, if transferred into the uterus.
If embryo testing is requested using PGT (formerly known as PGS or CCS), embryos are biopsied on the 5th or the 6th day of development and frozen individually. The biopsied DNA is then amplified and tested for chromosomal or genetic problems. The test results are reported within 5-7 business days typically. During this time, the patient will expect her period, which typically starts in 12-14 days after the egg retrieval. When the cycle starts, the uterus is then prepared for an embryo transfer. This type of a transfer is called a frozen embryo transfer (FET). Most transfers regardless of doing the PGT testing are frozen transfers today. Whereas this approach may result in higher pregnancy in some patients, embryos can also be transferred a few days after the egg retrieval in a ”fresh IVF cycle”. In fresh transfers cycles, PGT is not done because often times there is not enough time to accurately test the embryos.
6. THE EMBRYO TRANSFER (ET):
If PGT is done on the embryos, then only the chromosomally normal embryos are transferred. If PGT is not done, then the best quality embryos are transferred based on microscopic appearance and grading. At LA IVF, we commonly transfer only one embryo to minimize the risks associated with twins and high order multiples. We are not only able to accomplish high pregnancy rates with such an approach but also able to minimize the risk of having complications from multiples.
Embryos/blastocysts are transferred to the uterus via a thin catheter. This procedure is often conducted under ultrasound guidance with the patient on her back (in the lithotomy position) and with a full bladder. The procedure is usually painless and takes less than ten minutes to complete. Sometimes a prior trial embryo transfer points towards potential difficulty in transferring the embryo to the uterus. In such cases, the procedure may be performed with patient under anesthesia. In rare cases where tortuous or partial obstruction of the canal leading in to the uterus (i.e. the cervical canal) severely complicates conventional embryo transfer, a method known as trans-myometrial embryo transfer (TMET) can be used. With TMET, the patient is anesthetized and a needle is passed along the side of a transvaginal ultrasound probe, through the wall of the uterus into the cavity. A catheter is passed through the needle with its tip protruding into the uterine cavity. The needle is partially withdrawn and the embryo is injected into the endometrial cavity. After the embryo transfer the patient remains immobile for a short period of time and is thereupon discharged with specific instructions.
Embryo transfer is an important step in IVF and requires confidence, dexterity, skill and gentility. Once cleavage has begun, the embryo will continue to divide at regular intervals. (Embryos that divide the fastest are considered the healthiest and the most likely to implant.)
Embryo transfers should be performed under direct ultrasound guidance to ensure proper placement in the uterine cavity. This practice can significantly enhance embryo implantation/pregnancy rates and also allows visual participation of the patient/couple. We still prefer to perform embryo transfers when the patient has a full bladder, but alternatively it can be done with an empty bladder using the vaginal ultrasound approach. This facilitates the visualization of the uterus by ultrasound and would tilt the uterus into a straight position. The patient is allowed to empty her bladder following the embryo transfer. We also offer our patients oral diazepam (Valium) prior to the embryo transfer to relax them and reduce apprehension.
When the patient is in the proper position, and her bladder is adequately filled, the physician first inserts a speculum into the vagina to expose the cervix and then may clean the cervix with a solution to remove any mucus or other secretions. An abdominal ultrasound transducer is placed suprapubically on the lower abdomen and the uterus is visualized. The physician then informs the embryology laboratory that embryo transfer is imminent and awaits the arrival of the transfer catheter that will be loaded with the embryos. The physician gently guides the catheter through the patient’s cervix into the uterine cavity. When the catheter is in place, the embryologist or doctor carefully injects the embryos into the uterus, and the physician slowly withdraws the catheter. The catheter is immediately returned to the laboratory, where it is examined under the microscope to make sure that all the embryos have been deposited. Any residual embryos would be re-incubated, and the transfer process would usually be repeated to deliver the remaining embryos. Transfer of residual embryos neither harms the embryos nor reduces the pregnancy rates.
7. POST-EMBRYO TRANSFER MANAGEMENT
Immediately prior to being discharged following the embryo transfer procedure, an exit interview is conducted whereby the patient is given written instructions. Hormonal supplementation usually involves the administration of either intramuscular (IM) injection of progesterone or a vaginal suppository (micronized progesterone) until a blood pregnancy test is performed approximately 8-10 days later (the biochemical diagnosis of pregnancy). If the pregnancy test is negative or the plasma HCG levels fail to rise appropriately in the ensuing days, all hormonal support is discontinued. Hormonal support is continued until the 10-12th week of pregnancy in healthy pregnancies. An ultrasound examination is performed approximately 2-3 weeks after the biochemical diagnosis of pregnancy to visualize the pregnancy and hear the heartbeat. Pregnant patients are then followed closely to ensue the well-being of the fetus until 10 weeks. Once pregnancy is confirmed to be healthy, patients are then referred to their general obstetrician for prenatal care and delivery of the baby.