Related Experiment Videos
Urinary oestrogen patterns in long follicular phases
S D Harlow1, D D Baird, C R Weinberg
1Department of Epidemiology, University of Michigan, Ann Arbor, Michigan 48109-2029, USA.
Human Reproduction (Oxford, England)
|December 28, 1999
Summary
Longer menstrual cycles show diverse estrogen profiles, not necessarily low estrogen levels. This challenges assumptions linking long cycles to reduced breast cancer risk and increased osteoporosis risk.
Area of Science:
- Reproductive Endocrinology
- Gynecology
- Hormone Research
Background:
- Long menstrual cycles are linked to breast cancer and osteoporosis.
- Previous assumptions suggest low endogenous estrogen in women with long cycles.
- Daily estrogen profiles in long cycles remain undescribed.
Purpose of the Study:
- To investigate daily urinary estrogen profiles during the follicular phase of long menstrual cycles.
- To characterize estrogen patterns in women with follicular phases lasting 24 days or more.
- To compare estrogen concentrations in long cycles versus usual and short cycles.
Main Methods:
- Analysis of daily urinary estrogen profiles.
- Study included 416 women aged 21-42 years undergoing conception and non-conception cycles.
- Cycles were categorized by follicular phase length (long: ≥24 days, usual: 12-17 days, short: 7-11 days).
Main Results:
- Five distinct estrogen patterns were identified in long cycles.
- The most common pattern in long cycles indicated delayed dominant follicle emergence.
- Estrogen concentrations in long cycles were not substantially different from usual length cycles and not necessarily hypo-estrogenic.
Conclusions:
- Estrogen profiles in long menstrual cycles are heterogeneous.
- The assumption of consistently low estrogen in long cycles is not supported by this data.
- Further research is needed to understand the implications of these diverse estrogen profiles.