556 Obstetrics and Gynecology Board Review •••
❍ Approximately how many live births result in singletons, twins, and triplets?
Singletons: 60%.
Twins: 29%.
Triplets or more: 5%.
Unreported/miscarriage: 6%.
❍ What is the age of IVF patients?
More than two-third of IVF patients are 30 to 39 and 20% are over 40.
❍ How does frozen embryo live birth rates compare with fresh embryo live birth rates?
Frozen embryo rates are approximately 10% lower than fresh embryo live birth rates.
❍ What is ovarian hyperstimulation syndrome (OHSS)?
Ovarian enlargement in response to exogenous gonadotropin therapy.
❍ What are symptoms of OHSS?
Abdominal distention/pain, ascites, gastrointestinal problems, respiratory distress, oliguria, hemoconcentration,
electrolyte imbalance, and thromboembolism.
❍ What is the pathophysiology of OHSS?
Increased vascular permeability with the loss of fluid, protein, and electrolytes into the peritoneal cavity; thought
to be the result of vasoactive substances produced by the corpus luteum (VEGF).
❍ What is preimplantation genetic diagnosis (PGD)?
It is a procedure available to couples whose offspring may be at risk of genetic abnormality. This technique allows
couples to have their embryos screened prior to uterine transfer.
❍ How is PGD performed?
PGD begins by using the technique of embryo biopsy. A single cell is removed from a day 3 embryo containing six
to eight cells.
❍ What type of disorder can be detected by PGD?
X-linked disorder.
Single gene defects.
Age related chromosomal aneuploidies.
❍ What are two detection techniques currently used in PGD?
Fluorescence in situ hybridization (FISH) and polymerase chain reaction (PCR).
❍ What is the definition of aneuploidy?
Any deviation from an exact multiple of the haploid number of chromosomes, whether more or less.