Phthalate-Induced Ovulatory Dysfunction in Women

Increasing evidence suggests that exposure to environmental toxicants and endocrine-disrupting chemicals (EDCs) contributes to the prevalence of infertility in women. This is a major public health concern because exposure to certain EDCs is unavoidable for humans, and infertility in women leads to increased levels of stress, diminished social functioning, and impairments in physical and mental health resulting in a decreased quality of life. Our lab seeks to understand how certain EDCs cause fertility defects by disrupting the normal functions of the ovary, or female gonad. 

Our primary research focuses on one class of environmental toxicants and EDCs, called phthalates, and their ability to inhibit or impair ovulation, or the release of the egg from the ovary for fertilization. Phthalates are a group of chemicals that are used as plasticizers and solvents in a myriad of common consumer, medical, building, and cosmetic/personal care products. Such products include food and beverage containers, car upholstery, floorings/carpeting, roofing, wood finishes, blood/IV bags, medical tubing, surgical gloves, and enteric coatings of certain medicines. Important for women’s healthcare, phthalates are also abundant in makeup products, nail polish, hairspray, perfumes, and lotions. Due to their presence in these items, phthalates are ubiquitous in the environment, and it is estimated that 100% of the population is exposed to phthalates on a daily basis.

Control treated follicle vs. phthalate treated follicle

Although evidence suggests that phthalates target the female reproductive system, much less is known about the effects of phthalates on the ovary, especially ovulation. This is alarming because ovulation is the cornerstone for fertility and defects in ovulation are the leading cause of infertility in women.

The Hannon Lab uses mammalian model systems (rodent and human) to test the central hypothesis that exposure to phthalates adversely impacts several processes required for successful ovulation leading to diminished fertility. We have designed studies that mimic human exposure to phthalates by using validated phthalate mixtures and our findings will be directly translational to human health based on the use of our human model systems.

Our goal is to provide insight into the impact of phthalates and other EDCs on human reproductive health and fertility. By obtaining this understanding we can establish avenues to intervene on reproductive dysfunction and infertility caused by environmental exposures.

Regulation of Ovulation and Fertility in Women

In collaboration with Dr. Thomas Curry and Dr. Misung Jo in the department of obstetrics and gynecology, our lab is also interested in obtaining a complete knowledge of the events that occur during ovulation. From the beginning of this process to actual egg release from the ovary takes place over a span of 36 hours in women. During this critical window for fertility, the structure that contains the egg, called the follicle, undergoes massive biological changes that are driven by genes/proteins that mediate ovulation. Ovulatory mediators have been discovered in rodent models; yet, it is unknown if these mediators drive ovulation in women. Further, the existence of additional, new mediators of ovulation across species is unknown. Our lab uses human, monkey, and rodent ovarian model systems to identify novel mediators of the ovulatory process. By discovering these targets, our goal is to either facilitate fertility in infertile patients or to provide different contraceptive agents to those wishing to delay fertility. Further, these findings seek to establish new biomarkers for a woman’s fertility status. Since defects in ovulation are the leading cause of female infertility and because infertility can be mentally and physically debilitating, these studies will refine infertility treatments, decrease infertility costs, and provide a benefit to the overall healthcare of women.