Introduction

Reproductive function represents a rather unique endocrine system since its “goal” is the perpetuation of the species, not the individual. Hence its regulation in humans, which integrates both exogenous and endogenous factors, and represents a complex system with large within- and between-women variability in both the menstrual cycle length and the ovulatory cycle.

In human clinical practice various tools are routinely used to assess female reproductive status including keeping a menstrual diary, charting body temperature, or follicular ultrasound monitoring (Ecochard et al., 2001), but these methods are not appropriate for field situations, especially with less literate or illiterate subjects. Although measuring progesterone and oestradiol levels in serum is the gold standard, obtaining blood samples can be difficult in studies involving serial sampling, especially in developing countries, owing to ethical, logistical and cultural constraints. So the focus here is on the use of changes in hormonal profiles, collected by non-invasive methods, to examine the likelihood of ovulation occurring. In field situations this methodology can be applied to both literate and illiterate women.

The World Health Organisation (WHO) Collaborating Centre developed non-invasive immunoassay methods for measuring human steroid hormones from saliva and urine in the 1980s (Sufi and Donaldson, 1988; Sufi et al., 1985). This technique uses enzyme immunoassay to detect urinary pregnanediol-3-alpha-glucuronide (PdG) and oestrone-3-glucuronide (E1G), the urinary metabolites of progesterone and estradiol, respectively, throughout the menstrual cycle.