The upshot is that the relationship between BPA (Bisphenol-A) and fertility is unclear, despite studies attempting to uncover a link. Mostly, this is because the variables in the studies may not correlate as well to real-life circumstance.
BPA is most commonly found in the lining of aluminum cans and other packages, and in thermal receipts. It is also found elsewhere in the environment and very difficult to avoid, but generally the amounts found in humans are not harmful according the Food & Drug Association. The route of exposure is ingestion from exposed foods and drinks, inhalation of particles that BPA has attached to, and absorption via the skin.
BPA has effects on the body similar to estrogen. In this way, it disrupts the hormonal system whether it affects fertility in a significant way or not. Excess estrogenic activity in the body can cause fatigue, fibrocystic breasts, depression, and weight gain. BPA is recognized by the body as a weak estrogen, meaning it recognizes it enough to not make extra estrogen in its presence, but BPA isn’t as effective as estrogen in its reproductive roles. Estrogen’s role in fertility includes thickening the endometrial lining to prepare for implantation of fertilized egg, regulating the menstrual cycle, and it affects the trigger of ovulation.
A literature review on BPA and fertility, done in 2013, concluded that while studies on animal eggs using BPA do show a positive association for many fertility-related bodily processes, the implications are unknown for other species including humans.
One study’s attempt to explore the relationship between BPA and fertility consisted of gathering eggs from fertility clinic patients and exposing them to varying amounts of BPA. The experiment did show that high amounts of BPA decreased the maturation of exposed eggs, as well as abnormal maturity, and some acted as though they were fertilized but had not been (called ‘spontaneous activation’). These results seem provocative, except that these eggs were originally going to be discarded by the clinic for being possibly damaged. Furthermore, the amounts of BPA causing these effects are higher than those typically encountered in the environment. Therefore, the effect of BPA on healthy eggs is still not known. To quote one of the researchers, “Unexplained fertility is still unexplained.”