Early Follicular Growth Implicated in Age-Related Fertility Decline

Early follicle growth implicated in age-related fertility decline
Source: Human Reproduction 2003; 18: 495-501
Researchers compare follicle growth, ovulation, hormonal patterns, and endometrial development in older and younger women.

Study findings suggest that, even in the absence of any clear menstrual cycle disturbances, follicular development may begin earlier in the cycle as women age, potentially affecting fertility.

"The cause of declining fertility with age, in women who still have regular menstrual cycles, is not clear," say P. van Zonneveld (University Medical Center, Utrecht, The Netherlands) and co-authors.

The researchers used transvaginal sonography and blood sampling to evaluate follicle development, endometrial growth, and hormone patterns across the menstrual cycle in 26 women aged 41-46 years with no history of infertility, and 35 fertile women aged 22-34 years.

The older women had a shorter follicular phase and overall cycle, and an earlier follicle-stimulating hormone rise than the younger women, although clearly abnormal cycles were found in only two older women, as well as one younger woman. Follicle growth appeared to be "advanced" in the older women, starting as early as the luteal phase of the preceding cycle, with advanced selection and ovulation of the dominant follicle.

"An earlier start of follicle growth in a possibly less favorable hormonal environment, as well as a limited oocyte pool, may contribute to a decreased follicle and oocyte quality, resulting in diminished fertility in aging women," the researchers conclude.