A new study has linked preconception exposure to phthalates to women’s reproductive health. Identifying how phthalates decrease the odds of getting pregnant, mess with important reproductive hormones, and cause inflammation and oxidative stress, the study adds to a growing body of evidence about the negative effects of these chemicals.
Phthalates are a group of human-made chemicals commonly used as solvents, plasticizers and stabilizers in personal care products like soap, body lotion, perfume, nail polish, shampoo, hair gel and hairspray. They’re also in other products found around the house, such as vinyl flooring, plastic packaging, garden hoses and toys.
According to the US Centers for Disease Control and Prevention (CDC), people are exposed to phthalates by eating and drinking foods that have been in contact with the chemicals, with some exposure occurring from breathing in airborne particles. Studies have shown that exposure to some types of phthalates disrupts the endocrine system and increases inflammation and oxidative stress.
A new study by researchers at the University of Massachusetts (UMass) Amherst has examined the association between preconception phthalate exposure and a woman’s chances of getting pregnant and maintaining the pregnancy, and their effect on inflammation and oxidative stress.
“Phthalates are ubiquitous endocrine disruptors, and we’re exposed to them every day,” said Carrie Nobles, the study’s lead author.
The researchers analyzed data obtained as part of the EAGeR (Effects of Aspirin in Gestation and Reproduction) study, which followed 1,288 women during six menstrual cycles while trying to get pregnant and followed women who became pregnant throughout their pregnancy. The mean age of participants was 28. Data were adjusted for age, BMI, race/ethnicity, cigarette smoking and parity, or the number of times a woman has given birth to a fetus with a gestational age of 24 weeks or more.
“We were able to look at some environmental exposures like phthalates and how that relates to how long it takes to get pregnant,” Nobles said. “There was detailed data for each menstrual cycle, so we had a good handle on the date of ovulation and the timing of pregnancy when that happened.”
When the body breaks down phthalates, the metabolites are excreted in urine. The researchers analyzed 20 phthalate metabolites and reproductive hormones in participants’ urine samples and measured serum levels of C-reactive protein (CRP), an inflammation biomarker.
Overall, preconception urinary concentrations of several phthalate metabolites were associated with lower odds of getting pregnant within one menstrual cycle (fecundability), including the metabolites of di(2-ethylhexyl) phthalate (DEHP), di-n-butyl phthalate (DBP), and benzylbutyl phthalate (BzBP). There were no clear associations between phthalate metabolites and the risk of pregnancy loss.
“We found there were three parent compounds that seem to be most strongly associated with taking longer to get pregnant, although we saw a general trend toward it taking longer to get pregnant across the phthalates we looked at,” said Nobles. “As exposure got higher, we saw more and more of an effect.”
DEHP is in polyvinyl chloride (PVC) plastic products like toys, vinyl upholstery, shower curtains, adhesives, and some food packaging, as well as pesticides and cosmetics. DBP is found in hairspray, nail polish and some perfumes, amongst other household items. BzBP is in some handbags, belts and footwear and, to a lesser extent, in some personal care products.
Higher levels of some phthalate metabolites were associated with lower estradiol across the menstrual cycle and consistently associated with higher follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels. Estradiol is a steroid hormone that regulates the menstrual cycle; FSH and LH work in tandem to regulate ovulation. These hormones play an important role in the early establishment of pregnancy.
“This profile – estradiol staying low and follicle-stimulating hormone staying high – is actually something that we see in women who have ovarian insufficiency, which can happen with age as well as due to some other factors,” Nobles said. “Ovulation just isn’t happening as well as it used to.”
The researchers also found that women with higher levels of phthalate exposure also had higher levels of inflammation and oxidative stress, which can damage cells and DNA and lead to disease. They say the ubiquitous nature of phthalates makes it difficult for women to control their exposure despite taking precautions such as checking consumer product labels and choosing phthalate-free options.
“Women may be exposed to the parent compounds of these metabolites (DEHP, DBP, and BzBP) through multiple routes, including dust from flooring and other household items, absorption of personal care products including nail polish and fragrances, dietary exposures due to food packaging and contamination of food sources, and ingestion of contaminated drinking water,” said the researchers.
The study was published in the journal Environmental Health Perspectives.
Source: UMass Amherst
