In Vitro Fertilization (IVF)
In Vitro Fertilization (IVF) is a procedure used to fertilize an egg outside the woman’s body in a specialized laboratory when other simpler methods of conception have failed. Some common reasons for IVF are when the woman has blocked fallopian tubes or if the man has extremely low semen parameters.
Preparation for an IVF cycle: Evaluation of the uterine and tubal anatomy in the female partner with a Hysterosalpingogram (HSG) or Saline Infusion Sonogram (SIS) is important before an IVF cycle is undertaken to maximize the potential of achieving a pregnancy. Infectious disease testing is also obtained from both partners involved in the IVF cycle. Hormonal evaluation which usually includes tests for thyroid dysfunction, prolactin disorders and ovarian reserve testing are also customarily performed. A semen analysis from the male partner is also obtained. Where possible all abnormal testing is treated or addressed with the couple before the IVF cycle is commenced.
Oral contraceptive pills: Some treatment protocols include oral contraceptive pills to be taken for 2 to 4 weeks before gonadotropin injections are started in order to suppress hormone production or to schedule a cycle. Side effects include unscheduled bleeding, headache, breast tenderness, nausea, swelling and the risk of blood clots or stroke.
Ovulation Induction: A carefully designed ovulation induction protocol is picked by a physician to assure that the maximum numbers of eggs are obtained while attempting to protect the patient from complications such as the ovarian hyperstimulation syndrome (OHSS). Usually the protocol involves injectible fertility medication (gonadotropins) and GnRH analogs. Frequent monitoring with vaginal ultrasounds and hormonal levels is required for an optimal result. Once an adequate number of follicles are large enough per ultrasound with an appropriate rise of the estradiol level an HCG trigger shot in taken by the patient.
Egg Retrieval: 36 hours after the HCG shot and before the eggs actually ovulate, the egg retrieval is procedure is performed. The procedure is conducted while the patient is given intravenous sedation by an nurse anesthetist who will also monitor the patient. The nurse anesthetist assures that the patient is kept comfortable. Nearly always, the patient will not remember nor experience any pain with the procedure. A needle is guided from inside the vagina into each of the ovaries with vaginal ultrasound to ascertain that the needle is safely away from bowel, bladder, and large blood vessels. All follicles that are visualized and large enough per ultrasound are entered and aspirated of their contents. The aspirates are sent to the embryology laboratory for analysis. The eggs are separated from the follicular fluid and safely placed in an incubator for fertilization later in the day. The number of eggs obtained depends upon many factors such as the age of the patient, ovarian reserve, and the accessibility to the ovaries.
Fertilization: The eggs will then be fertilized by either of two methods. The first method is called ‘the conventional method’ and the second method is called ‘intra‐cytoplasmic sperm injection (ICSI)’. The IVF team of physicians and embryologists will decide which method is ideal for fertilization. It largely depends upon many factors with the couple undergoing treatment. Generally speaking, the conventional method allows a certain number of sperm per egg to be incubated in the same dish in the laboratory and allows the sperm to enter the egg by itself overnight. The ICSI procedure involves placing one sperm into the cytoplasm of the egg with a needle with a very sophisticated operative microscope. Fertilization is checked the following morning for either of the fertilization methods.
Embryo Transfer: The transfer procedure is usually performed either 3 or 5 days after retrieval depending upon the couple and the consensus of the IVF team. The number of embryos returned also depends upon age and other factors. Our center follows the American Society of Reproductive Medicine (ASRM) guidelines as outlined below. The transfer procedure is performed with a soft, flexible, delicate and thin catheter and with abdominal ultrasound guidance to assure that the catheter tip is placed at the optimal location, where the embryos will have the best chance to implant. The patient feels as if she were getting an extended pap smear. Pain or discomfort is rarely reported with this procedure. The remaining good quality embryos are usually frozen for future use in case the initial cycle is unsuccessful or more children are desired after a successful initial cycle.
Recommended limits on number of 2-3 day old embryos to transfer:
|Embryo Quality||age <35||age 35-37||age 38-40||age >40|
|Favorable||1 or 2||2||3||5|
Recommended limits on number of 5-6 day old embryos to transfer:
|Embryo Quality||age <35||age 35-37||age 38-40||age >40|
Assisted hatching: The cells that make up the early embryo are enclosed within a flexible membrane (shell) called the zona pellucida. During normal development, a portion of this membrane dissolves, allowing the embryonic cells to escape or “hatch" out of the shell. Only upon hatching can the embryonic cells implant within the wall of the uterus to form a pregnancy.
Assisted hatching is the laboratory technique in which an embryologist makes an artificial opening in the shell of the embryo. The hatching is usually performed on the day of transfer, prior to loading the embryo into the transfer catheter. The opening can be made by mechanical means (slicing with a needle or burning the shell with a laser) or chemical means by dissolving a small hole in the shell with a dilute acid solution.
Some programs have incorporated artificial or “assisted hatching" into their treatment protocols because they believe it improves implantation rates, and ultimately, live birth rates although definitive evidence of this is lacking. We discuss with the couple undergoing treatment whether assisted hatching ought to be considered.
Risks that may be associated with assisted hatching include damage to the embryo resulting in loss of embryonic cells, or destruction or death of the embryo. Artificial manipulation of the zygote may increase the rates of monozygotic (identical) twinning which are significantly more complicated pregnancies. There may be other risks not yet known.
Luteal Phase support: Progesterone and estradiol are hormones normally produced by the ovaries after ovulation. After egg retrieval in some women, the ovaries will not produce adequate amounts of these hormones for long enough to fully support a pregnancy. Accordingly, supplemental progesterone, and in some cases estradiol, are given to ensure adequate hormonal support of the uterine lining. Progesterone is usually given by injection or by the vaginal route (Endometrin®, Crinone®, Prochieve®, Prometrium®, or pharmacist‐compounded suppositories) after egg retrieval. Progesterone is often continued to the twelfth week of a pregnancy. Progesterone has not been associated with an increase in fetal abnormalities. Side effects of progesterone include depression, sleepiness, and allergic reaction. If the progesterone is given by an intra‐muscular injection it includes the additional risk of infection or pain at the injection site. Estradiol, if given, can be by oral, trans‐dermal, intramuscular, or vaginal administration. Side effects of estradiol include nausea, irritation at the application site if given by the trans‐dermal route and the risk of blood clots or stroke.
Pregnancy Test: A blood pregnancy test is performed approximately 12 days after the embryo transfer. If a pregnancy has occurred the patient will be followed with blood tests and eventually ultrasounds to confirm its viability and whether there is a multiple pregnancy present. If the pregnancy appears normal at 9‐10 weeks, the patient is than referred to her obstetrician.