Declining conception rates and the high incidence of female reproductive disruptions warrant evaluation of the impact of EDCs on female reproductive health.
Exposure to environmental endocrine disruptors during fetal development has been postulated to contribute to declining conception rates and increased incidence of female reproductive disorders such as oocyte aneuploidy, polycystic ovarian syndrome, and altered cyclicity, as well as endometriosis, uterine fibroids, fetal growth retardation, and pregnancy loss (Crain et al. 2008).
Alison Hadley, a former leader of the government's strategy on teenage pregnancy, said of the decline in conception among under-18s: "This is an incredible achievement which we should celebrate and is a great tribute to everyone who has worked so hard to bring down the rates.
Finally, the observed sleep, activity and mood disruptions that often develop pre- and peri-menstrually, in the absence of conception, may be byproducts of declining hormone levels [ 5].
This prompted an in-depth review: 3 local government areas where under-18 conception rates declined since 1998 were compared with 3 areas with similar demographics but where conception rates were static or increasing.
For example, human sperm quality and fertility are reportedly declining over time (Nordstrom Joensen et al., 2009) but effects on conception rates may become obvious only when the number of fertile sperm declines to a critical level.
Females' condition at conception generally declined as they got older, but this effect was attenuated among females older than about 15 years of age (Figure 2).
Results showed that, as expected from earlier research, the sex ratio of survivors of the conception cohorts declined as the number of mass layoffs increased above levels expected from autocorrelation.
While adult women have experienced declining fertility since 1970, this is not the case for adolescent girls (aged 15 19): adolescent conception rates range from 12.7 to 20.5% in the region (1, 2).
The conception that jellyfish blooms are a consequence of anthropogenic activities and the associated sensationalist headlines in the mass media4 have prompted jellyfish to become a symbol for the fragility and the declining health status of the world's oceans.
Our findings contradict the long-standing belief that declining GH and IGF levels, characterizing individual aging in vertebrate species, result primarily from endocrine deficiency, a viewpoint frequently used to promote the conception of hormonal replacement (Sonntag et al., 2005).
