In Vitro Fertilization (IVF)
In Vitro Fertilization
IVF or in vitro fertilization is the assisted reproductive procedure that revolutionized infertility medicine in 1978. Assisted reproduction refers to the handling of eggs (oocytes) and sperm outside the body and in a laboratory.
Since its auspicious start with the birth of Louise Brown, IVF has been perfected so that it yields very favorable success rates that vary with the diagnosis and age of the patient, but which are comparable to or exceed success achieved without any assistance.
Who are the best candidates for IVF?
Though originally indicated as a way to achieve pregnancy for women with damaged or absent fallopian tubes, IVF now is used for cases of unexplained female infertility, moderate to severe endometriosis or any female or male factor conditions that fail to respond to less aggressive treatment.
IVF is a carefully controlled and monitored four-step process, which includes:
- Controlled and monitored ovarian stimulation with hormonal medications;
- The egg retrieval;
- Fertilization of the eggs and sperm in the laboratory; and
- Embryo transfer to the uterus.
Successful IVF procedures occur after a careful orchestration of all these steps to produce the optimal conditions for a viable pregnancy to occur.
Controlled Ovarian Stimulation
The doctor will prescribe injections of follicle-stimulating hormonal medications that will induce the production of multiple mature follicles in addition to the one normally produced each month of a woman’s cycle. The fluid-filled follicles are sacs that contain the oocytes or eggs as they mature. Other hormones are used to prevent the ovaries from releasing the eggs from the follicles before they are ready.
We will carefully monitor the growth of the follicles through blood tests and ultrasounds as they increase in size before they are ready for ovulation. Blood tests give us an indication of your hormone levels and the ultrasounds preview the number and size of the follicles. These tests also help determine the best time to trigger ovulation and release the eggs.
We will administer the medication hCG (human chorionic gonadotropin) to trigger the release of oocytes from the mature follicles. The egg retrieval generally occurs 34-36 hours after this injection.
You will be given intravenous-conscious sedation, which will make you very sleepy, but the procedure will be painless. The doctor will use transvaginal ultrasound to visualize the location of the follicles and a thin needle to aspirate fluid from each mature follicle containing the eggs.
Fertilization in the Laboratory
The sperm sample from either the male partner or donor is carefully prepared in the laboratory for fertilization with the retrieved mature eggs. If the male partner has a low number or poor quality sperm, the embryologist will inject one sperm into the cytoplasm of the egg with a needle in a procedure called ICSI or intracytoplasmic sperm injection.
The following day, the embryologist will check to ensure fertilization has taken place and will continue to monitor the embryos’ development as they grow in a special culture designed to mimic the fallopian tube’s environment. Genetic screening or pre-implantation genetic diagnosis (PGD), if necessary, will be performed on day three (3) before the embryo is implanted.
Your doctor and laboratory team will determine the optimal time for the embryo transfer. Typically embryos are transferred either on day three after fertilization (six to eight-cell embryos) or at the blastocyst stage, which is more advanced embryo development five to six days after fertilization.
We will prepare the lining of your uterus with progesterone medication to accept and implant the embryos. Your doctor will determine the number of embryos to be transferred based on your individual diagnosis, age and treatment history. The transfer procedure is painless; we recommend rest for at least 24 hours after the procedure.
This procedure, also known as assisted zona hatching, is a micromanipulation technique that “thins” the outer coating or zona pellucida of the embryo immediately prior to transfer to the uterus. The zona is a layer of proteins that protects the embryo until it reaches the blastocyst stage of development.This thinning helps the embryo “hatch” once it is implanted in the uterus and is beneficial to women 37 years of age and older who have thicker zonas.
Any excess embryos from the IVF cycles can be frozen, which is also known as embryo cryopreservation. The embryos can be stored in the IVF laboratory until the individual or couple undergoes another IVF cycle or decides to stop their family building and embark on another course.
A frozen embryo cycle is cost-effective because it precludes the need for a woman to take additional hormonal medications to stimulate the ovaries. Though some frozen embryos do not survive thawing, success rates for frozen embryo cycles are comparable to the fresh variety.