Neighborhood disorder linked to increased pregnancy testosterone levels

New research has uncovered a significant relationship between the level of neighborhood disorder a pregnant woman experiences and increased levels of testosterone during pregnancy. This finding, published in BMC Pregnancy and Childbirth, opens new avenues in understanding how our environment can directly influence prenatal development.

The genesis of this research lies in a body of evidence suggesting that where we live can significantly affect our health. Prior studies have shown that characteristics of neighborhoods, such as the prevalence of crime or the condition of buildings, can influence a range of health issues from heart disease to mental health disorders.

These findings led researchers to wonder about the specific impact of neighborhood environments on pregnant women and their unborn children. Notably, earlier studies have linked neighborhood characteristics to pregnancy outcomes, like preterm births, but how these environments affect pregnancy at a physiological level remained less understood.

“Our lab focuses on environmental and psychosocial exposures that impact maternal and child health particularly during pregnancy,” said study author Zorimar Rivera-Núñez, an assistant professor at Rutgers School of Public health and a resident faculty at Rutgers Environmental and Occupational Health Sciences Institute (EOHSI).

“Pregnancy is a very critical time for child health, and adverse exposures during this time can impact health later in life including in childhood, adolescence and adulthood. In this case, we studied alterations in sex-steroid hormones during pregnancy as a possible pathway or mechanism for psychosocial stressors to impact the baby’s health.”

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“These hormones are essential to maintain pregnancy and to sustain baby growth. Evidence suggest that neighborhoods characteristics impact pregnancy outcomes such as preterm birth and low birthweight, here we explore as sex steroid hormones as a potential pathway for those adverse outcomes.”

To explore this, researchers conducted a study involving 262 pregnant women who were in the first trimester of their pregnancies. These women were recruited from outpatient obstetric clinics associated with Rochester University Medical Center between December 2015 and April 2019.

To ensure a focused study group, the researchers set specific criteria for participation: the women had to be at least 18 years old, carrying a single baby, free from major substance abuse or psychotic illnesses, and able to communicate in English. Those with major endocrine disorders, high-risk pregnancies, or significant obstetric problems were excluded from the study.

Once enrolled, these women embarked on a journey through their pregnancies with the research team, attending face-to-face visits during each trimester. The researchers were particularly interested in two aspects: the women’s neighborhood environment and their hormone levels.

To gauge the level of stress in their neighborhoods, a City Stress Inventory questionnaire was administered in the third trimester. This tool is a well-established method to measure neighborhood stress, comprising 18 questions about various aspects of neighborhood life, including the presence of vacant buildings and personal experiences of violence. The answers to these questions were then used to develop a comprehensive picture of the level of disorder and violence in each woman’s neighborhood.

Alongside this, the researchers were tracking changes in the women’s hormones. Blood samples collected each trimester were analyzed for five key hormones: estrone, estradiol, estriol, total testosterone, and free testosterone. These hormones were chosen because of their crucial role in pregnancy and fetal development. The technique used for this analysis was liquid chromatography with tandem mass spectrometry, a highly accurate method for hormone measurement.

The researchers found that as the level of neighborhood disorder increased, so did the concentrations of testosterone in the women’s blood across their pregnancies. This was particularly true for women carrying male babies. In contrast, no significant relationship was observed between neighborhood disorder and the four other hormones measured.

“It is interesting that we observed alterations in androgen levels, which have been associated with stress in animal studies,” Rivera-Núñez told PsyPost. “This is similar to what we observe with other stressors that alter endocrine pathways.”

The relationship between neighborhood conditions and hormone levels was most pronounced in the third trimester of pregnancy. The researchers found that the higher the level of neighborhood disorder, the greater the increase in testosterone during this critical period of fetal development.

Overall, the findings highlight that “where you live impact your health, in this case pregnancy health,” Rivera-Núñez said.

While the study found a correlation between neighborhood disorder and increased testosterone levels during pregnancy, it’s crucial to understand that correlation does not imply causation. The exact mechanisms behind this association remain unclear, and further research is necessary to unravel these complex interactions.

“Study participants come for Rochester and we may not be able to generalize these findings to the United States as a whole,” Rivera-Núñez noted. “Also, while we know stress impact pregnancy outcomes the pathways for this impact are still unknown. Our study is one of the first ones trying to determine the possible pathways, as such similar studies are needed in other populations.”

“I would like to reiterate that maternal stress and neighborhood characteristics have an impact on population health and this impact may have long-term consequences, particularly for exposures that occur while baby is in utero,” she added.

The study, “Associations between neighborhood stress and maternal sex steroid hormones in pregnancy“, was authored by Megan C. Hansel, Hannah R. Murphy, Jessica Brunner, Christina Wang, Richard K. Miller, Thomas G. O’Connor, Emily S. Barrett, and Zorimar Rivera-Núñez.