Field methods and strategies for assessing female reproductive functioning

Abstract

A detailed understanding of female reproductive functioning is important to many disciplines including anthropology, evolutionary theory, demography, psychology, and biomedicine. In this article, I describe strategies and methods that have been used successfully in community‐based studies of human reproduction, many in remote locales, to produce high quality biomarker data. These techniques are applicable to a wide range of research questions and populations, and to persons from adolescence through senescence. I give particular attention to the inherent challenges imposed by the cyclical and somewhat unpredictable nature of the hypothalamic‐pituitary‐ovarian axis including the necessity and difficulty of ascertaining the timing and occurrence of ovulation, the limits of different sampling regimes for capturing fluctuations in reproductive hormones, and the critical importance of recognizing and, when possible, reducing selection bias. I discuss the relative advantages and disadvantages of collecting saliva, urine, and dried blood spots, and describe some of the subtleties involved in collecting contamination‐free samples. Once samples are collected, they must be stored in a manner that minimizes degradation; I describe techniques to keep samples cold even without access to electricity or dry ice. I also discuss various issues that should be considered during initial discussions with a laboratory and when samples are assayed by the laboratory. I include examples of techniques that have worked well in actual field studies, and examples of flawed analytical approaches that should be avoided. With these and other tools, even under technology‐sparse conditions, researchers can investigate variability in human physiology across the breadth of human habitats.

Measuring attack on self: The need for field‐friendly methods development and research on autoimmunity in human biology

“…Interileukin‐10 is also measurable from saliva but has been shown to be susceptible to variation in acute stress (Szabo et al, 2016), so may be of minimal use as a biomarker of autoimmunity. Further, reproductive hormones can be measured in saliva (Kozloski et al, 2014; Trumble et al, 2013; Vitzthum, 2020) and can be analyzed in conjunction with other biomarkers of autoimmunity to test sex‐related hypotheses associated with AIID. In general, saliva is non‐invasive, easy to collect, and inexpensive (Javaid et al, 2016), so population‐based research on AIID could consider targeting these kinds of biomarkers.…”

“…In the last decade, biomarker analysis from field‐friendly (i.e., affordable; minimally‐invasively collected; easily‐stored) samples has come into focus within the fields of human biology and related disciplines (Eick et al, 2019; Eick et al, 2020, 2020; Goldman et al, 2017; Hoke, McCabe, Miller, & McDade, 2018; Ice & James, 2007; McDade, 2014; McDade, Williams, & Snodgrass, 2007; Mei, Alexander, Adam, & Hannon, 2001; Valeggia, 2007; Vitzthum, 2020). This shift in focus has opened doors for population‐based research (i.e., interdisciplinary, multi‐method human health research focused on specific groups of individuals) because in many cases, venous blood draw, magnetic resonance imaging, tissue sampling, and other more invasive, specialized, or expensive methods for assessing health‐ and physiology‐related metrics are difficult or impossible in non‐clinical settings (McDade et al, 2007).…”

Recognizing normal reproductive biology: A comparative analysis of variability in menstrual cycle biomarkers in German and Bolivian women

“…The delay is attributable, in part, to the technological and logistical challenges of investigating the reproductive physiology of populations in remote locales (Leslie & Little, 2003; Vitzthum, 2021). Furthermore, in the natural fertility populations in which anthropologists typically work, a large segment of the fecund women of reproductive age are either pregnant or breastfeeding, and thus not experiencing menstrual cycles.…”

“…Cycle length (duration in days) is the most studied feature of the menstrual cycle. Bookended by the first day of menstrual bleeding, menses can be recorded on a calendar or other device and the days counted (Vitzthum, 2021). Several studies (Creinin et al, 2004; Jukic et al, 2008) have reported various biases in recalled cycle length and variability (also referred to as predictability or regularity) including a preference for reporting 28 or 30 day lengths, which would tend to give the impression of less cycle variability than actually exists.…”

Woman's reproductive span

“…women's reproductive span has an impact on wom-nen's reproductive decisions inclduing when to get pregnant, spacing between pregnancies, and finally when to have the last birth. The span also influences the fertility levels in the population [4].…”