Exploring menstrual health: Insights from the Avon longitudinal study

Exploring menstrual health: Insights from the Avon longitudinal study | Image Credit: © Alena – © Alena – stock.adobe.com.

In a recent article, instigators evaluated available data about menstrual cycles characteristics, which should be considered when managing menstrual health.

Many women experience problematic menstrual cycle features such as heavy menstrual bleeding, irregular periods, absence of periods, severe pain, premenstrual syndrome (PMS), and frequent or infrequent cycles. Rates of these features differ based on age, population, definition of feature, and contextual attitudes toward menstruation.

These features are associated with adverse physical and mental health outcomes such as amnesia, infertility, sleep disturbances, pain sensitivity, anxiety, and depression, making it vital to understand risk factors. However, data about risk factors of problematic menstrual cycle features is lacking.

To promote available research of menstrual cycle data, investigators described results from the Avon Longitudinal Study of Parents and Children (ALSPAC). ALSPAC is a longitudinal birth cohort including pregnant women from Avon, United Kingdom, with an expected delivery date from April 1, 1991, to December 31, 1992.

There were 2 samples included in the analysis, the first including mothers and the second daughters. Mothers reported their menstrual cycle features from index pregnancy to menopause, while daughters either self-reported or had their mother report menstrual cycle features from age 8 to 24 years.

A total of 17 questionnaires from index pregnancy to 28 years after childbirth were used to collected data on absence of periods, regularity, menstrual cycle length, heaviness, PMS-related symptoms, and pain in mothers. Menstrual cycle features were also collected at clinic assessments, during which mothers were aged a mean 47.4 to 52.6 years.

Data on daughters’ menstrual cycle characteristics was initially reported by mothers through puberty questionnaires at ages 8.1, 9.6, 10.6, 11.6, and 13.1 years. Afterward, daughters self-reported their characteristics in questionnaires at ages 14.6, 15.5, 16, and 17 years, with child-based questionnaires also completed by mothers at ages 13.1, 13.8, and 16.5 years.

Clinic assessments of daughters’ menstrual cycle characteristics were performed at ages 11.7, 12.8, 13.8, 15.5, 17.8, and 24 years. Finally, child-completed questionnaires were conducted at ages 19.6 and 21 years.

Participants in both samples reported the exact length of their menstrual cycles by the number of days. Outliers included up to 90 days among mothers and up to 150 days among daughters. 

Causes of these irregular lengths include amenorrhea episodes and participants misunderstanding the questions. Peaks of 5 days were reported, indicating some participants reported days bleeding rather than cycle length.

While amenorrhea was measured as a binary variable, most participants reported a reason for not having a period in the past 3 months, including pregnancy, surgery, chemotherapy, contraception, menopause, and not starting periods yet. Cycle regularity was also reported as a binary, with not regular, too irregular to estimate cycle length, and very or moderately irregular periods being classified as the participant having irregular periods.

Among mothers, bleeding could be defined as very, moderately, mild, or not at all. However, for daughters, heavy and prolonged bleeding could not be separated.Outliers in prolongedbleeding were observed, with some participants in both samples reporting up to 60 days bleeding.

For pain, investigators were able to report moderate-to-severe pain as pain associated with a participants’ period. However, for daughters, differences in questions need to be considered when evaluating responses, as some questions asked about “severe cramps” and others about “pain with your period.” At age 15.5, severe or moderate pain was reported by 61.7% of participants and severe only by 16.4%.

Multiple methods of using PMS-related variables were identified. A binary variable could be used to classify specific problems, or binary variables can be devised separately or together for before and during periods. Since there are a wide variety of PMS-related symptoms, it is worth noting that not all participants will interpret their symptoms the same.

This data shows a wide variety of menstrual health characteristics reported by ALSPAC.These factors should be considered when evaluating menstrual health.

Reference

Sawyer G, Howe LD, Fraser A, Clayton G, Lawlor DA, Sharp GC. Menstrual cycle features in mothers and daughters in the Avon Longitudinal Study of Parents and Children (ALSPAC). Wellcome Open Res. 2023;8:386. doi:10.12688/wellcomeopenres