CLINICAL ASPECTS OF EMBRYO IMPLANTATION From the Perspective of Tissue Perfusion

Hypothesis: Pelvic perfusion is the pivotal factor for the outcome of in vitro fertilisation (IVF) treatment once clinical and embryological variables are controlled for their effect. Demonstration of Hypothesis: In a series of three studies, the clinical aspects of embryo implantation were examined from the perspective of tissue perfusion. Epidemiological Study: Clinical and embryological data were evaluated to predict multiplicity of implantation and ongoing pregnancy in IVF treatment. Oocyte and embryo quality were appraised and the impact of the number of embryos transferred was assessed. Study on In-vivo Vascular Physiology: The prognostic role of utero-ovarian perfusion and its pharmacological manipulation with low dose aspirin was evaluated in the outcome of IVF treatment. Serum, follicular fluid vascular endothelial growth factor (VEGF) and vascular endothelial growth factor receptor (VEGFR) concentrations were correlated with Doppler indices. Study on In-vivo Endometrial Physiology: Endometrial receptivity (in terms of endometrial thickness and echo-pattern) and VEGF-VEGFR concentrations were evaluated with regards to the outcome of frozen-thawed embryo replacement (FTER) during natural and hormone replacement cycles. Results: The epidemiological study showed that the outcome of IVF treatment was closely associated with the severity of subfertility. Ovarian reserve and response to stimulation were the key factors. The probability of pregnancy was affected by the number and quality of oocytes and by their fertilisation rate and the cleavage rate of the resulting embryos. The potential to provide mature oocytes and high quality embryos was an inherent characteristic of the ovaries and independent of