Prior to the introduction of IVF, many couples had no hope of having a child that was a product of their eggs and sperm. IVF opened the door for the treatment of conditions such as male infertility, tubal disease, unexplained infertility, and advanced pre maternal age.
Following the birth of Louise Brown, the world’s first test tube baby, physicians and embryologists refined the many techniques associated with IVF to improve the success rate of the process. Today, clinics are now reporting per cycle success rates of 50% or higher in certain patient categories. IVF has become the most efficient treatment option for infertility the world over.
The Latin terms, in vitro, literally translates to “in glass.” In practice, patients’ eggs and sperm meet in specially designed plastic test tubes or dishes, and this is where fertilization will take place. It takes another three to five days for embryos to develop from the fertilized eggs. Once this has occurred, the laboratory team confers with the couples’ physician as to the quality of the embryos, and the selection as to which one(s) is made based on the lab findings as well as the couples’ wishes.
To get to this point several steps will have taken place. First and foremost is the determination by the fertility specialist of what is causing the fertility problems. The answer may be obvious in nature, but many times it is not, and it at this point that crucial decisions are made as to how to proceed most effectively. Often times a couple may believe they have a certain condition – and they may have – but thorough fertility testing frequently reveals more than one challenge to their fertility that was unknown. Physical exams, blood tests, semenology, ultrasound and extensive patient histories are all-important keys to success with IVF.
All women undergoing a cycle of IVF require ovulation induction therapy usually with the fertility drug FSH in order to produce several eggs during one of her ovulation cycles. The protocols, referred to as controlled ovarian hyperstimulation, or COH, involve taking a series of intramuscular and subcutaneous injections, in addition to oral medication over a period of time ranging from two to three weeks.
During this time, blood tests and ultrasound images of her ovaries will inform her physician of her response to the medication, and the dosages may be adjusted accordingly to optimize the outcome. The goal is to ripen as many eggs from both ovaries as possible for that one ovarian cycle.
The ripened eggs are removed under intravenous sedation in an operating or special procedure room. This procedure is painless and takes just minutes to perform. The male partner produces a specimen by masturbation and submits his specimen to a member of the laboratory team. Extreme care is taken to ensure the right eggs meet the right sperm in the laboratory.
The lab team works to produce high-quality embryos for all patients. Sometimes a couple will generate many more embryos than are safe to put back all at once. These spare embryos can be frozen (cryopreserved) for use later. Embryos can remain frozen for many years. (See Text Below)
The embryo transfer is an atraumatic procedure to place one or more embryos into the womb of the female partner. Ultrasound is frequently employed to assist the physician in accurately placing the embryos in an optimal spot for implantation of the embryos in the uterine lining. This procedure requires no sedation and takes about five minutes to perform. A blood test about 12 days later will determine if pregnancy has taken place.
Sometimes patients need additional IVF laboratory procedures to improve (A) the chances of successful fertilization,(B) successful “take” of the transferred embryos, and (C) identification of embryos that have either a normal complement of chromosomes, or will not result in a pregnancy that carry a specific genetic mutation. The IVF Laboratory can assist in (A) by a procedure called intracytoplasmic sperm injection, or ICSI. Improving the chances of implantation (B above) by transferred embryos in certain patient categories can be accomplished by a technique called assisted hatching (AH).
Chromosomal or genetic analysis of preimplantation embryos (C above) has helped thousands of couples worldwide fulfill their dreams of a child free of inherited disease, and this is also available through the IVF laboratory. Preimplantation Genetic Diagnosis (PGD)and its companion procedure, Preimplantation Genetic Screening, as well as ICSI, AH and embryo cryopreservation techniques are further described on this Web site.
Whether the above procedures additional to the routine handling of sperm, eggs and embryos is right for a couple is determined through the evaluative process between the infertility physician and the couple. Our Center was rated in the top 10 ART centers in the United States in a poll taken by Child Magazine in 2005.
Sometimes more embryos are created from an IVF cycle than can be safely placed into the uterus. The number of embryos replaced varies according to numerous factors such as female age, causes of infertility, etc. Transferring too many embryos can result in high order births (>3) with all of the accompanying potential medical issues.
When more embryos exist that can be safely transferred, they are often cryopreserved. Cryopreservation involves embryo freezing and thawing for future IVF cycles. The process involves transferring the embryos through various solutions while gradually lowering their temperature, being careful not to rupture the cell membrane. Thawing can be thought of as the freezing process “in reverse”.
The advantage of using cryopreserved embryos is that stimulation with fertility drugs to develop multiple eggs is not necessary. The cost of injectable fertility drugs is a large component of IVF cost. Because stimulation is not needed, ultrasound and estradiol measurements are not necessary further reducing cost. The number of office visits is also dramatically reduced.
The disadvantage of using cryopreserved embryos is that the success rates are lower than fresh embryos. In our practice the success rates for fresh embryos are comparable to cryopreserved embryos. The number of years a frozen embryo will remain viable is not know, however, many pregnancies have been produced from embryos over ten years old. Experience with freezing other body tissues suggests very long term viability.