In vitro fertilization (IVF) is a process by which egg cells are fertilized in vitro, that is, by sperm outside of the womb. IVF is a major treatment in infertility when other methods of assisted reproductive technology have failed. Assisted reproductive technologies (ART) include multiple techniques that allow gamete manipulation outside the body and have evolved greatly over the last 3 decades.
IVF involves egg retrieval from the ovary, fertilization in the laboratory (fluid medium), and replacement of the zygote in the patient’s uterus. The first live birth resulting from this technique occurred in June 1978.
Assisted reproductive techniques have been used for > 30 years, reporting an increasing number of cycles treated, an increasing pregnancy rate, and an increase in live births per cycle (from 6.6% in 1985 to 53.9% (in women < 35 y) in 2016) for IVF. In 2003 there were 122,872 ART cycles (99.4% were IVF cycles), whereas in 2006, 41,343 live-birth deliveries were reported. Based on CDC’s 2016 Fertility Clinic Success Rates Report, there were 263,577 ART cycles performed at 463 reporting clinics in the United States during 2016, resulting in 65,996 live births (deliveries of one or more living infants) and 76,930 live born infants.
One of the most important prognostic predictors for pregnancy is the age of the female partner. Younger women face better rates and despite the evolution of ART throughout the years, women over 40 face low birth rates, due to advanced reproductive age and aging of the ovary. Table 59–1 presents data according to the National Summary and Fertility Reports of the US Department of Health and Human Services.
Table 59–1.In vitro fertilization. ||Download (.pdf) Table 59–1. In vitro fertilization.
|Cycles Performed in Relation to Age Group |
| ||< 35 y ||35–37 y ||38–40 y ||> 40 y |
|Number of cycles performed ||39,302 ||39,023 ||17,191 ||> 13,000 |
|Outcomes According to Age Group |
| ||< 35 y ||35–37 y ||38–40 y ||41–42 y |
|% cycles resulting in pregnancy ||38.3 ||32.0 ||23.1 ||19.0 |
|% cycles resulting in live births ||46.5 ||38.4 ||27.4 || |
Approximately 39% of patients who undergo egg retrieval will become pregnant with sonographic documentation of an intrauterine pregnancy (clinical pregnancy); 82% of these patients will carry to term. Many “biochemical pregnancies” occur, but these should not be included in pregnancy statistics. A biochemical pregnancy is one in which serum levels of human chorionic gonadotropin (hCG) rise and then fall before sonographic detection of pregnancy is possible. Eggs are almost always obtained by aspiration, and under ordinary circumstances, approximately 75% of eggs will fertilize and cleave. The clinical pregnancy rate of approximately 34% per embryo transfer per IVF cycle (women < 35 years old) is > 20–25% pregnancy rate per cycle observed in spontaneous conceptions in the general population.