No evidence of increased uterine vascular impedance with patient ageing following IVF

A study was conducted to determine if uterine vascular impedance increases with advancing age in women undergoing ovarian stimulation for IVF. A group of 162 women who had undergone conventional IVF and embryo transfer was subdivided into three subgroups by age: 30-34 years (n = 49), 35-39 years (n = 79) and 40-44 years (n = 34). The pulsatility index (PI) and resistance index (RI) of the right and left uterine arteries were measured at baseline, on the day of oocyte retrieval, and at the mid-luteal phase. There were no differences in the average PI or RI by age at any phase of the cycle. In all age groups, the luteal phase values of PI and RI were lower than those observed earlier in the cycle. Endometrial thickness was not associated with age. There was no significant correlation between PI, RI and serum oestradiol and progesterone concentrations at any phase of the cycle. Ovarian response, as measured by average number of oocytes retrieved, decreased significantly with age. Thus, reduced pregnancy rates in older women undergoing ovarian stimulation are more likely to occur because of oocyte quality and quantity rather than uterine senescence. If future studies determine that the use of ovarian stimulation does decrease implantation rates more in older versus younger women, a mechanism other than increased uterine vascular impedance must be sought.