Assisted reproductive technology (ART) is by definition any treatment or procedure that includes the handling of oocytes and sperm or embryos outside the body for the purpose of establishing a pregnancy. In vitro fertilization (IVF) is the most common assisted reproductive technology procedure. The first in vitro fertilization baby was conceived in 1978 (Louise Brown) in Lancashire, England. in vitro fertilization has been used in the United States since 1981.
In vitro fertilization (IVF): A process including controlled ovarian hyperstimulation, surgical removal (retrieval) of oocytes, fertilization in the laboratory, and transcervical transfer of embryos into the uterus.
Gamete intrafallopian transfer (GIFT): A procedure that involves removing oocytes from a woman’s ovary, combining them with sperm, and using laparoscopy to assist in placing the unfertilized oocytes and sperm into the fallopian tubes.
Zygote intrafallopian transfer (ZIFT): A procedure that involves removing oocytes from a woman’s ovary, fertilizing them in the laboratory with sperm, then placing the single-cell embryo (zygote) directly into the fallopian tube utilizing laparoscopy.
Tubal embryo transfer (TET): A procedure that involves removing oocytes from a woman’s ovary and fertilizing them in the laboratory with sperm. The resultant embryo(s) are placed directly into the fallopian tube utilizing laparoscopy 2-3 days later.
Donor oocytes: Eggs that are removed from one woman’s ovaries to be used by another for in vitro fertilization Indications often include premature ovarian failure, gonadal dysgenesis, recurrent in vitro fertilization failure, natural menopause, and inheritable disorders.
Gestational surrogacy: Treatment by which the gametes of the intended parents (genetic parents) are used to produce embryos, which are subsequently transferred to a woman who agrees to act as a host or surrogate carrier of the pregnancy.
Microsurgical epididymal sperm aspiration (MESA): A technique whereby a small needle is used to extract fluid and relatively mature sperm directly from an epididymal tubule.
Testicular sperm extraction (TESE): A procedure for extracting sperm by removing a small sample of testicular tissue through an incision in the testes under local anesthesia.
Intracytoplasmic sperm injection (ICSI): A micro manipulation technique that involves injecting a sperm directly into an egg in order to facilitate fertilization.
Assisted hatching (AH): A technique in which the zona pellucida (outer shell of the egg) is chemically or mechanically thinned prior to embryo transfer in order to improve the likelihood of subsequent hatching and implantation of the embryo.
Preimplantation genetic diagnosis (PGD): A technique used during in vitro fertilization to test embryos for genetic disorders (aneuploidy or structural chromosomal abnormalities), inheritable single gene disorders, or gender, prior to embryo transfer. The procedure can involve evaluating the chromosomal composition of the oocyte via the extruded polar body, removing one or two blastomeres from the cleavage stage embryo, or by biopsy of the trophoectoderm of the blastocyst stage.
Success rates for in vitro fertilization centers are difficult to quantify because they are site-specific and depend on numerous factors. These include but are not limited to: patient characteristics, degree of ovarian stimulation, embryo culture quality, number of embryos transferred, and transfer technique. In general, success rates are reported using the following terminology:
- • Pregnancy rate: definition varies from a positive serum or urine βhCG to live birth
- • Clinical pregnancy rate: the percent of patients with at least one gestational sac in the uterine cavity with fetal cardiac activity
- • Live birth rate: percentage of patients with a live birth from an assisted reproductive technology cycle
- • Implantation rate: the number of clinical pregnancies divided by the number of embryos transferred
The Centers of Disease Control and Prevention (CDC) reports the most recent assisted reproductive technology success rates from reporting centers in the US. In 2003, the total number of assisted reproductive technology cycles reported was 112,872 while the number of live babies born as a result of assisted reproductive technology cycles was 35,785- Of all the assisted reproductive technology procedures performed, 74% were fresh, nondonor egg cycles. Of all the cycles cancelled, 82.9% were due to inadequate egg production. The rate of spontaneous abortion increases dramatically as the maternal age increases. The overall live birth rate per retrieval for different assisted reproductive technology procedures using fresh, nondonor eggs was as follows:
- • In vitro fertilization without intracytoplasmic sperm injection (intracytoplasmic sperm injection), 33.4%
- • In vitro fertilization with intracytoplasmic sperm injection, 31.9%
- • Gamete intrafallopian transfer 20.8%
- • Zygote intrafallopian transfer 25.9%
- • Combination of vitro fertilization with or without intracytoplasmic sperm injection and either GIFT or ZIFT, 28.3%
It is important to remember the success rates vary depending on the factors listed above, in addition to patient diagnosis. For example, in 2003 the highest live birth rate for fresh, nondonor cycles was in the ovulatory dysfunction infertility group (33.9%), while the lowest success rate was in the group with diminished ovarian reserve [14.3%]. The success rates also vary dramatically based on maternal age (Table: In vitro fertilization pregnancy success rates based on maternal age, 2003).
Table: In vitro fertilization pregnancy success rates based on maternal age, 2003
|Maternal Age (in years)||Live Births/Cycle|
- 1 The infertility work-up involves a thorough evaluation of both male and female partner.
- 2. Indications for assisted reproductive technology include male factor infertility, unexplained infertility, ovulatory disorders and ovarian failure.
- 3. Advanced assisted reproductive technology procedures include PGD, oocyte donation and gestational surrogacy.
- 4. Interpretation of success rates must consider the in vitro fertilization center, patient characteristics, stimulation protocols, number and quality of embryos transferred and transfer techniques.
- 5. Complications with assisted reproductive technology are rare but include bleeding, infection, ovarian hyperstimulation and multiple pregnancy.