In 2001, the Stages of Reproductive Aging Workshop (STRAW) defined seven stages of adult women's lives into three broad categories: reproductive, menopausal transition and post-menopause. Each also had subcategories defined by menstrual cycle data and endocrine studies.
However, the STRAW staging system applied only to a narrow range of women. A decade later, researchers published updated criteria and a modified staging system in the journal Menopause. It now applies to all cisgender women regardless of age, body mass index, demographic or lifestyle.
The Origins of STRAW
In July 2001, 27 experts on reproductive aging gathered to devise a staging system and clarify premenopause terminology.
The group decided that the stages of a reproductive aging system must do the following:
- Rely on objective data.
- Use only readily available, relatively inexpensive and reliable tests.
- Prospectively place women in the right stage.
- Avoid overlap between stages.
Each of the seven stages was broken down by the length of the stage, description of menstrual cycles and follicle-stimulating hormone (FSH) level. Although antral follicle count (AFC) determined by ultrasonography of the ovaries was considered, it ultimately was not included because there was not enough research at the time.
Updates to Reproductive Aging Stages
Researchers and practitioners from five countries regrouped in September 2011 to update the criteria based on advances in reproductive research and patient care that had taken place in the interim, including an improved understanding of ovarian function.
Renamed STRAW + 10, the stages are now as follows:
- Reproductive -5: The earliest reproduction stage, beginning with menarche and lasting a variable duration. Menstrual cycles are variable to regular. Antimüllerian hormone (AMH), FSH, and inhibin-B levels are normal. AFC is normal.
- Reproductive -4: Peak reproduction stage lasting a variable duration. Menstrual cycles are regular. AMH, FSH, and inhibin-B levels are normal. AFC is normal.
- Reproductive -3b: Late reproduction stage lasting a variable duration. Menstrual cycles are regular. FSH level remains within the normal range, but AMH and inhibin-B begin to decrease. AFC begins to decline.
- Reproductive -3a: Late reproduction stage lasting a variable duration. There are subtle flow and length changes to the menstrual period and cycle. FSH level becomes variable, and AMH and inhibin-B continue to decrease. AFC is low.
- Menopausal transition -2: Early menopause stage lasting a variable duration. Menstrual cycle length begins to vary (seven or more days different than normal). FSH level is variable but continues to rise, and AMH and inhibin-B levels are low. AFC is also low.
- Menopausal transition -1: Late menopause stage lasting one to three years. More than two menstrual cycles are skipped, or amenorrhea lasts more than 60 days. FSH level continues to rise, typically now greater than 25 IU/L. AMH and inhibin-B levels are low. AFC is also low. Vasomotor symptoms are likely.
- Postmenopause +1a: The stage immediately following the final menstrual period, during which amenorrhea lasts 12 months. This stage lasts approximately one year. FSH level is variable but continues to rise. AMH and inhibin-B levels are low. AFC is very low. Vasomotor symptoms are most likely.
- Postmenopause +1b: Still in early postmenopause, this stage lasts approximately one year. FSH level is variable but continues to rise. AMH and inhibin-B levels are low. AFC is very low. Vasomotor symptoms are most likely.
- Postmenopause +1c: Still in early postmenopause, this stage lasts between three and six years. FSH level stabilizes, and AMH and inhibin-B levels are very low. AFC is very low.
Postmenopause +2: The final stage that lasts the rest of the patient's life. Symptoms of urogenital atrophy increase.
Applying the STRAW Staging System in OB/GYN Practices
Because of the original objective of using only readily available, relatively inexpensive and reliable tests to help determine reproductive age, the STRAW staging system can be used by physicians across the globe.
By testing AMH, FSH and inhibin-B levels in the blood and obtaining AFC via transvaginal ultrasound, doctors can help patients set realistic expectations about their reproductive status. After all, age alone does not determine reproductive age; some patients might be surprised by their results.
Patients in the peak reproductive stage (-4) who do not desire to have children should be counselled on effective birth control options, whether temporary or permanent. Some may choose to freeze their oocytes to leave the possibility of pregnancy open in the future. If the patient is in late reproduction (-3a/b), they will likely require the assistance of a reproductive endocrinologist and assisted reproductive technology to become pregnant. Patients in early menopausal transition (-2) might need to consider donor oocytes.
Start by determining the patient's reproductive goals. Have an honest but empathetic conversation with the patient, using the stages of reproductive aging chart as a visual aide to improve understanding. Formulate a realistic plan together, and offer referrals to appropriate reproductive specialists.
