Phthalates - A Wild Card in Infertility and PCOS?

Phthalates ("thal-ates") are high-production-volume synthetic chemicals found in innumerable plastics and other common consumer products. Recent epidemiologic evidence suggests that women have a unique exposure profile to phthalates, which raises concern about the potential health hazards posed by such exposures.

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Where Can You Find Them?

Globally, more than 18 billion pounds of phthalates are used each year, primarily as plasticizers in flexible polyvinyl chloride (PVC) products. Phthalates are found in most PVC products including vinyl upholstery, tablecloths, shower curtains, raincoats, and soft-squeeze children's toys. Phthalates are used as inert ingredients in many sprays including pesticides and many consumer products such as cosmetics and wood finishes. Phthalates are also used as adhesives, defoaming agents, solvents, and lubricants.

Phthalates are approved for use in medical devices such as tubing, blood bags, and dialysis equipment and is also used to manufacture the 500 million pairs of disposable medical exam and sterile surgical vinyl gloves produced annually. Phthalates are used to impart flexibility to plastics, but they leach from plastic products into the environment over time. Given their high production volume, common use, and widespread environmental contamination, humans are exposed to these compounds through ingestion, inhalation, and skin exposure on daily basis.

Are You Exposed?

The Agency for Toxic Substances and Disease Registry estimates that the maximum daily exposure to one of the phthalates, DEHP, is about 2 mg per day for the general population. However, occupational and medical exposures can reach much higher level.

A recent study by the Centers for Disease Control and Prevention found phthalate metabolites in the urine of more than 75% of subjects tested. The CDC study also found that women of reproductive age had significantly higher urinary levels of one of the phthalates than other sex/age groups. These higher levels may be due to the fact that phthalates are used in many beauty products including perfume, lotion, and nail polish. Thus, women have a unique exposure profile, which raises a concern about the potential health hazards posed by such exposures.

Decreased Pregnancy Rates, Premature Breast Development?

Limited studies in human populations suggest an association between phthalate exposure and adverse reproductive health outcomes. For example, chronic occupational exposure to high levels of phthalates is associated with decreased rates of pregnancy and higher rates of miscarriage in female factory workers. Higher urinary phthalate levels correlated with pregnancy complications such as anemia, toxemia, and preeclampsia in women living near a plastics manufacturer.

Although occupational exposure is limited to a select population, women have exposures to phthalates in beauty and consumer products on a daily basis. During pregnancy and delivery, both the mother and fetus may be exposed to phthalates through medical devices. Exposure to the fetus in utero is a concern because some phthalates are developmental toxicants. Puerto Rican girls with premature breast development had higher levels of blood phthalates compared to other girls, suggesting an association between phthalate exposure and abnormal reproductive development.

Research with lab animals has shown that phthalates interfere with the ovary's ability to produce estrogen and thus prevent ovulation. Some animals also developed polycystic ovaries. What exactly phthalates do in the ovaries isn't entirely clear, but they may disrupt the timing of the growth and differentiation of the follicle so that it "skips" the ovulatory phase and goes into the post-ovulatory phase without ovulation actually occurring.

In addition, your liver has to work hard to detoxify phthalates. In this process, oxidant stress (production of damaging free radicals) can result. The risk of potential liver cancer is also increased. There is also some concern that phthalates could lead to defects in the developing fetus.

There is No "Safe" Level

Is there a "safe" level of phthalates? No one really knows. But all the news so far is bad and none of it good. One common phthalate (DEHP) has been removed from children's products intended for mouthing, such as pacifiers. In our view, the less exposure you have, the better -- especially if you are trying to get pregnant or are pregnant now.

You can reduce your exposure by being observant. Notice what plastic or synthetic products you come in contact with. Do you know what is in the cosmetics you are using? When you open a sealed consumer product, do you detect a slight plastic or chemical smell? Do you use vinyl gloves in your job? Did you let that new plastic raincoat air out in the sun before putting it into the closet?

There's no need to be paranoid about plastics and petrochemical pollution. On the other hand, total inaction is clearly not a good option. Chemical pollution of our environment is a developing threat to your reproductive and overall health. Therefore, you should take some steps to minimize your exposure. You can also help your liver to metabolize and detoxify some of these chemicals by taking vitamin/mineral supplements that help your liver do this important job.

Source: Lovekamp-Swan T et al, Mechanisms of phthalate ester toxicity in the female reproductive system, Environ Health Perspect. 2003 Feb;111(2):139-45