Background Fecundity declines in older women are associated with decreased ovarian function and oocyte quality, but little research is available on endometrial receptivity in older women. This study aimed to assess follicular development and endometrial receptivity, and to evaluate ultrasonic parameters in predicting endometrial receptivity during the implantation window in older women.
Methods For this prospective case-control study, 224 older women and 215 women under the age of 35 were recruited. The follicular development and endometrial thickness were monitored by transvaginal ultrasound before ovulation. During the implantation window, defined as 6 to 7 days after ovulation, the pulsatility index (PI) and resistance index (RI) of the uterine arteries and subendometrial region were calculated based on colour Doppler, and the endometrial volume, vascularization index (VI), flow index (FI) and vascularization flow index (VFI) were also determined using the VOCAL imaging program with 3-D mode power Doppler. The ultrasonic parameters were used to assess endometrial receptivity in older women.
Results The serum anti-Mullerian hormone (AMH) concentration and antral follicle count (AFC) were significantly lower in older women than in controls ( P <0.05). The average diameter of the dominant follicle was significantly smaller, and the subendometrial region RI was significantly higher in older women compared with controls ( P <0.05). The normal ovulation rate was significantly lower in older women than in controls ( P <0.01). The subendometrial region RI was significantly higher, and the endometrial VI, FI, and VFI were significantly lower in older women compared with controls ( P <0.05). The biochemical pregnancy rate, clinical pregnancy rate and ongoing pregnancy rate of older women were significantly lower than those of controls ( P <0.05). The best ultrasonic parameter for predicting endometrial receptivity during the implantation window in older women was VI, followed by FI.
Conclusions Older women present decreased serum AMH concentrations and AFC, defined as indicators of ovarian reserve function. Older women are characterized by decreased follicular development and endometrial receptivity, which may lead to fecundity disorders.