The Impact of Assisted Reproductive Technology on Gynecologic Surgery
Hey-Joo Kang
Zev Rosenwaks
DEFINITIONS
Controlled ovarian hyperstimulation—Administration of exogenous gonadotropins to induce growth of multiple ovarian follicles within a single menstrual cycle.
Developmental states—Morula—The stage between 72 and 96 hours after insemination, from the 16-cell stage to formation of the blastocyst. Blastocyst—The stage consisting of an inner cell mass from which the fetus develops and a trophectoderm from which the placenta develops. It is distinguished from the morula by the presence of a fluid-filled cavity.
Embryo transfer—The delivery of viable embryos to the uterine fundus for implantation. This is traditionally done transcervically or less commonly by laparoscopic cannulation of the fallopian tubes.
Intracytoplasmic sperm injection (ICSI)—Procedure by which a single sperm is injected directly into a mature oocyte assisted fertilization.
Mature oocyte—An oocyte at metaphase II of meiosis. Fertilization may occur at this stage of development.
Noncommunicating hydrosalpinx—Accumulation of distal tubal fluid that is unable to pass into the peritoneal cavity.
Oocyte—The immature female gamete.
Oocyte retrieval—The removal of oocytes after controlled ovarian hyperstimulation by ultrasound-guided needle aspiration. In rare instances, laparoscopic retrieval may be necessary.
Ovarian hyperstimulation syndrome (OHSS)—A complication of assisted reproductive technology that occurs almost exclusively with the use of gonadotropin stimulation. It is a condition of vascular hyperpermeability secondary to the release of vasoactive substances (vascular endothelial growth factor, tumor necrosis factor-alpha, interleukins) from the overstimulated ovaries. The transudation of proteinrich fluid from the intravascular to the extravascular compartment can lead to ascites, hemoconcentration, electrolyte imbalance, or hepatic and renal dysfunction. Severe OHSS can lead to vascular collapse, acute respiratory distress syndrome (ARDS) and even death.
Prezygote—The stage of pronuclear formation after penetration of the mature (MII) oocyte by spermatozoon. At this stage, male and female pronuclei are evident as well as the second polar body. This is the stage immediately preceding syngamy, the fusion of two nuclei to form a single nucleus of the zygote.
Zona pellucida—The glycoprotein membrane surrounding the plasma membrane of an oocyte.
Zygote—Single cell stage after pronuclear breakdown (syngamy) but before first cleavage.
ASSISTED REPRODUCTIVE TECHNOLOGY
Assisted reproductive technology (ART) is inclusive of any procedure involving fertilization of the oocyte outside the body. The first live birth from ART was reported in 1978 by Patrick Steptoe and Robert Edwards following laparoscopic retrieval of a single oocyte from a naturally stimulated ovary. The most frequently practiced ART procedure is in vitro fertilization (IVF). It involves a sequence of events beginning with controlled ovarian hyperstimulation, harvesting of oocytes, fertilization with spermatozoa, culturing of embryos, and replacement into the uterine cavity. Also under the umbrella of ART are laparoscopic tubal transfer of gametes (gamete intrafallopian transfer; GIFT), zygotes (zygote intrafallopian transfer; ZIFT), and embryos (tubal embryo transfer; TET). These techniques have largely been supplanted by IVF in light of their requirement for laparoscopy and considerable technical advances in both IVF and embryo culture conditions.
Assisted Reproductive Technology and the Expectations of Pregnancy
Consideration should first be made to the success rates of ART without surgical intervention. If this is deemed reasonable, it may be prudent to forgo surgery—and the inherent risks therein—and proceed directly to IVF. The decision to proceed with surgical intervention also requires detailed knowledge of its impact on subsequent pregnancy rates and should only be entertained if pregnancy rates could be significantly improved or the need for ART eliminated altogether.
Data on ART outcomes are collected every year to provide information to prospective patients as well as clinicians. The 2010 data from the Society for Assisted Reproductive Technology (SART) report pregnancy rates for fresh and frozen nondonor oocytes per cycle of IVF (Table 20.1). Success rates are clinic specific, and this information is available through http://sart.org.
Female age is the single most important predictor of IVF success rate due to the direct relationship between advancing female age and genetic instability of the oocyte. Over 90% of maternally derived aneuploidy stems from meiosis I chromosomal segregation errors. Two main mechanisms for oocyte aneuploidy have been described by Fragouli and colleagues. The first occurs exclusively during meiosis I with premature division of a chromosome into its two sister chromatids, followed by their random segregation. The second error is nondisjunction of entire chromosomes during meiosis I and meiosis II leading to hyperhaploid (n = 24) and hypohaploid (n = 22) gametes. As a result, advancing age of the female partner is inextricably
coupled with a decline in pregnancy and live birth rates. Coincidental with age, ovarian reserve also plays a major role in a woman’s reproductive potential. Thus, any discussion of prognosis should be made in the context of ovarian reserve assessment.
coupled with a decline in pregnancy and live birth rates. Coincidental with age, ovarian reserve also plays a major role in a woman’s reproductive potential. Thus, any discussion of prognosis should be made in the context of ovarian reserve assessment.
TABLE 20.1 2010 Success Rates of IVF Cyclesa Using Fresh Embryos from Nondonor Oocytes | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
ASSISTED REPRODUCTIVE TECHNOLOGY AND ENDOMETRIOSIS
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
