Common chemical may disrupt pregnancy hormone

 

• Phthalates, which manufacturers commonly add to plastics, have been the subject of much research over the last 2 decades.
• Experts consider several phthalates to be endocrine disruptors and reproductive toxicants.
• According to a recent study, phthalates may negatively affect hormones that the placenta produces during pregnancy.

Phthalates are commonly used synthetic chemicals in plastics and personal care items.

A recent study, which appears in Environmental International, shows a possible link between exposure to phthalates and the disruption of an important hormone necessary to sustain a healthy pregnancy.

The Consumer Product Safety Improvement Act of 2008 limited the use of a handful of phthalates in many household products, especially those that children use. However, these chemicals and many others like them are still present in everyday goods.

Environmental exposureTrusted Source, which can occur by ingestion or inhalation or through the skin, means that most people have measurable levels of these ubiquitous chemicals in their body.

The placenta produces corticotropin-releasing hormone (CRH), the level of which increases throughout the course of pregnancy. The brain also produces CRH as part of the body’s stress response.

During pregnancy, the level of placental CRH is up to 10,000 times higherTrusted Source than it is in those who are not pregnant. The concentration of placental CRH tends to increase later during pregnancy, and researchTrusted Source has shown it to regulate labor-promoting contractions.

However, when CRH levels are excessively high or rise rapidly earlier in pregnancy, issues such as preterm birth, fetal growth problems, high blood pressure, gestational diabetes, or postpartum depression may result.

CRH and phthalates

The recent study was one of the first to examine the effect that phthalates have on placental CRH. Study co-author Emily Barrett, Ph.D., associate professor of biostatistics and epidemiology at the Rutgers School of Public Health in Piscataway, NJ, spoke with Medical News Today.

Barrett explained that scientists “have spent many years learning about how exposure to phthalates in humans impacts fetal development and, by extension, children’s health.”

“In fact,” she continued, “we’ve shown that prenatal phthalate exposure appears to increase the odds of preterm birth and, after birth, [phthalates] may alter growth, neurodevelopment, and more. These effects may be through changes in key hormones like testosterone, estrogens, and thyroid hormones.”

“What stimulated our interest in this topic was that we recognized a gap in the literature. No one had looked at whether phthalates interfere with corticotropin-releasing hormone.”

The Conditions Affecting Neurocognitive Development and Learning in Early Childhood study, or CANDLE, recruited 1,018 pregnant women receiving prenatal care at selected clinics in Shelby County, TN, from 2001 to 2011.

The researchers collected urine samples from each participant during two prenatal visits. One visit occurred at 16–29 weeks gestation and the other at 22–39 weeks. They measured urinary phthalate metabolites to assess phthalate exposure.

The team found that the presence of various phthalates was associated with higher placental CRH levels in mid-pregnancy and a drop in CRH levels later in the pregnancy.

The hormone levels were highest in the women who developed pregnancy complications, such as gestational diabetes and high blood pressure.

The authors list several strengths and limitations of the study. The most notable strength was the large number of participants, of whom more than half were Black women. People of Color are typicallyTrusted Source underrepresented in pregnancy studies, but they may experience higher phthalate exposures in lifestyle and consumer goods.

Limitations include the fact that the researchers only tested each woman twice during their pregnancy. Also, some phthalates are short-livedTrusted Source within the human body, so a single spot urine test only represents recent exposure and may over- or underestimate exposure levels throughout pregnancy.

Source: Medical News Today