Childhood conditions influence adult progesterone levels

Background Average profiles of salivary progesterone in women vary significantly at the inter- and intrapopulation level as a function of age and acute energetic conditions related to energy intake, energy expenditure, or a combination of both. In addition to acute stressors, baseline progesterone levels differ among populations. The causes of such chronic differences are not well understood, but it has been hypothesised that they may result from varying tempos of growth and maturation and, by implication, from diverse environmental conditions encountered during childhood and adolescence. Methods and Findings To test this hypothesis, we conducted a migrant study among first- and second-generation Bangladeshi women aged 19–39 who migrated to London, UK at different points in the life-course, women still resident in Bangladesh, and women of European descent living in neighbourhoods similar to those of the migrants in London (total n = 227). Data collected included saliva samples for radioimmunoassay of progesterone, anthropometrics, and information from questionnaires on diet, lifestyle, and health. Results from multiple linear regression, controlled for anthropometric and reproductive variables, show that women who spend their childhood in conditions of low energy expenditure, stable energy intake, good sanitation, low immune challenges, and good health care in the UK have up to 103% higher levels of salivary progesterone and an earlier maturation than women who develop in less optimal conditions in Sylhet, Bangladesh (F9,178 = 5.05, p < 0.001, standard error of the mean = 0.32; adjusted R2 = 0.16). Our results point to the period prior to puberty as a sensitive phase when changes in environmental conditions positively impact developmental tempos such as menarcheal age (F2,81 = 3.21, p = 0.03) and patterns of ovarian function as measured using salivary progesterone (F2,81 = 3.14, p = 0.04). Conclusions This research demonstrates that human females use an extended period of the life cycle prior to reproductive maturation to monitor their environment and to modulate reproductive steroid levels in accordance with projected conditions they might encounter as adults. Given the prolonged investment of human pregnancy and lactation, such plasticity (extending beyond any intrauterine programming) enables a more flexible and finely tuned adjustment to the potential constraints or opportunities of the later adult environment. This research is the first, to our knowledge, to demonstrate a postuterine developmental component to variation in reproductive steroid levels in women

The impact of developmental conditions on adult salivary estradiol levels: Why this differs from progesterone?

Women living in energetically stressful conditions have significantly lower baseline salivary steroid levels compared to those in affluent environments. Developmental hypotheses suggest that interpopulation variation in ovarian function results from contrasting environments experienced during growth. We use a migrant study of Bangladeshi women to test this hypothesis. We compared middle-class women (19-39 years) who migrated to London, UK, at different life-stages (pre and postmenarche), with Bangladeshi sedentees, second-generation British-Bangladeshis, and white British women living in similar London neighborhoods (total n = 227). We analyzed levels of salivary estradiol for one menstrual cycle, together with data on anthropometry, diet, lifestyle, and migration and reproductive histories. Results from multiple linear regression models, controlling for anthropometric and reproductive variables, show no significant differences in baseline estradiol levels between groups whether all cycles or just ovulatory cycles are analyzed. We also found no correlation between age at migration or time since migration on estradiol levels, nor between adult estradiol levels and age at menarche. Our results differ from previous reports of significantly lower salivary estradiol levels in populations living in more extreme ecological settings. They also contrast with our previous findings of significant intergroup differences in baseline levels of salivary progesterone. However, women who spent their childhood in Sylhet have a lower proportion of ovulatory cycles compared to women who developed in Britain. These group differences in ovulation frequency indicate more qualitative effects of contrasting developmental environments. We discuss possible explanations for differences in response between progesterone and estradiol, as well as broader implications of our findings