General Departmental Seminar Series
A Hierarchial Bayesian Approach to Modeling Embryo Implantation Following in vitro Fertilization
Vanja Dukic, Brown University
Thursday, March 9, 2000, 2:00-3:00 p.m.
14th Floor Conference Room, WARF
In-vitro fertilization and embryo transfer (IVF-ET) is a method for treating infertility in which oocytes are fertilized in vitro, and one or more resulting embryos are transferred into the uterus. We utilize the so-called 'EU model' which describes embryo implantation as the product of two random variables, E (number of viable embryos) and U (uterine receptivity indicator), and extend it to a Bayesian hierarchical framework to account for correlation between embryo viabilities from the same couple and give explicit characterization of patient-level heterogeneity. One difficulty associated with fitting of this model is that some subjects have zero observed implantations; the resulting posterior distribution is improper, and informative priors for key parameters are needed. The model is used to assess the effect of different covariates on both uterine receptivity and embryo viability. A specific concern is the effect of hydrosalpinx on uterine receptivity. Hydrosalpinx is a build-up of embryo-toxic fluid in the Fallopian tubes that sometimes leaks to the uterine environment. In addition to providing estimates of covariate effects, our analysis indicated substantial subject-level heterogeneity with respect to embryo viability, suggesting the utility of a multi-level model.
This is joint work with Dr. Joseph W. Hogan, supported by Grant HD-35996 from NIH (NICHD).
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