Donor Sperm Screening Although the use of fresh donor semen is associated with higher pregnancy rates than the use of frozen specimens, both the Centers for Disease Control and
Prevention and the American Society for Reproductive Medicine recommend the use of frozen samples (96,98,99). This recommendation stems from the increasing incidence of human immunodeficiency virus (HIV) infection in the general population and the lag time between HIV infection and seroconversion. Currently, semen donors are screened for HIV infection, hepatitis B, hepatitis C, syphilis, gonorrhea, chlamydia, and cytomegalovirus infections, all of which may be transmitted through semen. All cryopreserved samples are quarantined for 6 months, and the donor is retested for HIV before clinical use of the specimen. Donors are likewise questioned about any family history of genetically transmitted disorders, including both Mendelian (e.g., hemophilia, Tay-Sachs disease, thalassemia, cystic fibrosis, congenital adrenal hyperplasia, Huntington disease) and polygenic or multifactorial conditions (e.g., mental retardation, diabetes, heart malformation, spina bifida). Those with a positive family history of these conditions are eliminated as donor candidates (96).
Figure 32.4 Live births per embryo transfer comparing use of a patient’s own versus donor oocytes. (Adapted from CDC Reproductive Health. 2009 Assisted Reproductive Technology Success Rates. National Summary and Fertility Clinic
Reports. http://www.cdc .gov/nccdphp/drh/art.htm.)
Successful live birth is dependent on the age of the eggs used, not on the age of the mother. Women in their 40s can achieve the same pregnancy success rates as 25year-olds if they use donor eggs that are provided by younger women.
Reproductive aging is associated with abnormalities in the oocyte meiotic spindles that lead to chromosome alignment errors and increase rates of conceptus aneuploidies, particularly trisomies. This serves to increase the risk for spontaneous pregnancy loss and thereby decrease live birth rates in older women (100,105). A large study based on the Danish national registry estimated the rates of clinically recognized spontaneous pregnancy loss for various age groups to be 13.3% (12 to 19 years), 11.1% (20 to 24 years), 11.9% (25 to 29 years), 15.0% (30 to 34 years), 24.6% (35 to 39 years), 51.0% (40 to 44 years), and 93.4% (older than 45 years) (106). In addition, using sensitive hCG assays in women during their reproductive years, 22% of all pregnancies were found to be lost before they could be clinically diagnosed (107).
Ovarian reserve refers to the size of the nongrowing, or resting, primordial follicle population in the ovaries. This, in turn, presumably determines the number of growing follicles and the “quality” or reproductive potential of their oocytes (105). Tests of ovarian reserve are often used, but the predictive values of these tests for fertility potential are limited, particularly when normal testing is found in older women and abnormal testing is documented in younger women. The tests appear to be better suited for determining how the ovaries will respond to pharmacologic doses of exogenous gonadotropins in terms of follicle count, the number of oocytes produced, serum estradiol levels during stimulation, the duration of stimulation, and the quantity of exogenous gonadotropins required in a given cycle (108). However, unlike age, the results of ovarian reserve testing are poorly predictive of pregnancy outcomes (109–111). These tests appear to be more indicative of oocyte quantity rather than quality (110).