Household chemicals have been seen as a hindrance to conception

American scientists have found a link between the impact on women's bodies of phthalates, which are part of detergents and other household chemicals, and difficulties with pregnancy.

Phthalates are esters and salts of phthalic acid. Substances of this group are widely used to give softness, strength, flexibility and elasticity to plastic products. But the use of phthalates, which also serve as solvents and stabilizers, is not limited to this. They can be found in shampoos and cosmetics, in medical products, toys and various other products.

Phthalates are often referred to as "ubiquitous" for this prevalence. The Environmental Protection Agency (EPA) estimates that more than 213,000 tons of these substances are produced worldwide each year.

However, once in the human body, phthalates can accumulate and harm health. Studies have shown that these compounds can disrupt endocrine and sexual functions. Scientists have previously found links between phthalate exposure and premature births, neurodevelopmental disorders in children and chronic kidney disease.

In a new paper published in the journal Environmental Health Perspectives, Carrie Nobles, an assistant professor at the University of Massachusetts Amherst, and colleagues from other U.S. universities, tracked how phthalate metabolites before conception can affect women's fertility and pregnancy.

To analyze the scientists used data from another American study, known by the abbreviated name EAGeR (Effects of Aspirin in Gestation and Reproduction). During it they evaluated the effect of taking low doses of aspirin on the level of live births. EAGeR participants were 1,128 healthy women between 18 and 40 years old who were trying to get pregnant and were seen in a number of U.S. clinics between 2007 and 2011.

At inclusion in the program, subjects underwent blood and urine tests and were administered a questionnaire. Among other things, the women reported their age, ethnicity, bad habits, weight, height, and other personal information. In addition, participants tracked their menstrual cycle and fertility windows. If pregnancy occurred, the women were continued to be followed for the duration of the pregnancy.

In the University of Massachusetts study, experts examined the women's urine samples for the presence of 20 phthalate metabolites and compared the data with information about the participants' menstrual cycle. They found that elevated values of three of them - mono-(2-ethylhexyl)phthalate, monobutyl phthalate and monobenzyl phthalate - correlated most strongly with a lower likelihood of getting pregnant.

The authors also found that subjects with elevated phthalate levels had increased values of high-sensitivity C-reactive protein and serum isoprastans before conception. The former is considered by medical professionals to be a marker of inflammatory processes, while the latter is an indicator of oxidative stress in the body.

Those exposed to phthalates also had lower values of estradiol and higher values of follicle-stimulating hormone. This hormonal background is characteristic of women with ovarian insufficiency. However, the researchers found no associations with pregnancy termination.

According to Carrie Nobles, in the light of the new findings, authorities may need to consider tightening regulation on the use of phthalates.