A new study ties the odds of conception to the advantages of the neighborhood a woman lives in.
In a cohort of more than 6,000 women who were trying to get pregnant without fertility treatments, the probability of conception was reduced 21%-23% per menstrual cycle when comparing the most disadvantaged neighborhoods with the least disadvantaged.
“When disadvantaged neighborhood status was categorized within each state (as opposed to nationally), the results were slightly larger in magnitude,” wrote authors of the study published online in JAMA Network Open.
Among 6,356 participants, 3,725 pregnancies were observed for 27,427 menstrual cycles of follow-up. Average age was 30, and most participants were non-Hispanic White (5,297 [83.3%]) and had not previously given birth (4,179 [65.7%]).
When the researchers compared the top and bottom deciles of disadvantaged neighborhood status, adjusted fecundability ratios (the per-cycle probability of conception) were 0.79 (95% confidence interval [CI], 0.66-0.96) for national-level area deprivation index (ADI) rankings and 0.77 (95% CI, 0.65-0.92) for within-state ADI rankings. ADI score includes population indicators related to educational attainment, housing, employment, and poverty.
“These findings suggest that investments in disadvantaged neighborhoods may yield positive cobenefits for fertility,” the authors wrote.
The researchers used the Pregnancy Study Online, for which baseline data were collected from women in the United States from June 19, 2013, through April 12, 2019.
In the United States, 10%-15% of reproductive-aged couples experience infertility, defined as the inability to conceive after a year of unprotected intercourse.
Reason Behind the Numbers Unclear
Mark Hornstein, MD, director in the reproductive endocrinology division of Brigham and Women’s Hospital and professor at Harvard Medical School, both in Boston, said in an interview that this study gives the “what” but the “why” is harder to pinpoint.
What is not known, he said, is what kind of access the women had to fertility counseling or treatment.
The association between fertility and neighborhood advantage status is very plausible given the well-established links between disadvantaged regions and poorer health outcomes, he said, adding that the authors make a good case for their conclusions in the paper.
The authors ruled out many potential confounders, such as age of the women, reproductive history, multivitamin use, education level, household income, and frequency of intercourse, and still there was a difference between disadvantaged and advantaged neighborhoods, he noted.
Hornstein said his own research team has found that lack of knowledge about insurance coverage regarding infertility services may keep women from seeking the services.
“One of the things I worry about it access,” he said. “[The study authors] didn’t really look at that. They just looked at what the chances were that they got pregnant. But they didn’t say how many of those women had a workup, an evaluation, for why they were having difficulty, if they were, or had treatment. So I don’t know if some or all or none of that difference that they saw from the highest neighborhood health score to the most disadvantaged – if that was from inherent problems in the area, access to the best health care, or some combination.”
Discussions Have Focused on Changing Personal Behaviors
Discussions on improving fertility often center on changing personal behaviors, the authors noted. “However, structural, political, and environmental factors may also play a substantial role,” they wrote.
The findings are in line with previous research on the effect of stress on in vitro outcomes, they pointed out. “Perceived stress has been associated with poorer in vitro fertilization outcomes and reduced fecundability among couples attempting spontaneous conception,” the authors noted.
Studies also have shown that living in a disadvantaged neighborhood is linked with comorbidities during pregnancy, such as increased risks of gestational hypertension (risk ratio for lowest vs. highest quartile: 1.24 [95% CI, 1.14-1.35]) and poor gestational weight gain (relative risk for lowest vs. highest quartile: 1.1 [95% CI, 1.1-1.2]).
In addition, policies such as those that support civil rights, protect the environment, and invest in underresourced communities have been shown to improve health markers such as life expectancy.
Policy decisions can also perpetuate a cycle of stress, they wrote. Disadvantaged communities may have more air pollution, which has been shown to have negative effects on fertility. Unemployment has been linked with decreased population-level fertility rates. Lack of green space may result in fewer areas to reduce stress.
A study coauthor reported grants from the National Institutes of Health during the conduct of the study; nonfinancial support from Swiss Precision Diagnostics GmbH, Labcorp, Kindara.com, and FertilityFriend.com; and consulting for AbbVie outside the submitted work. No other author disclosures were reported. Hornstein reported no relevant financial relationships.
This article originally appeared on MDedge.com, part of the Medscape Professional Network.