16 Sep Stanford Studies Show Differences Between Races in Rates of Birth Complications

A pregnant woman and friends pose for a photo at a baby shower on November 10, 2018 in Pittsburg. (Ray Saint Germain / Bay City News)

By Thomas Hughes
Bay City News

Two new studies from the Stanford University School of Medicine revealed significant differences between races in rates of birth complications caused by high blood pressure and anemia during pregnancy.

The studies, published Sept. 7 in the peer-reviewed medical journal Obstetrics and Gynecology, looked at the prevalence of birth complications caused by chronic hypertension, or high blood pressure, in pregnant women and the rates of complications from iron-deficiency anemia, excluding patients with anemia caused by genetic factors.

The studies found that pregnant Black women had more than double the rate of both medical issues compared to pregnant white women. That led to higher rates of pre-eclampsia, hemorrhage and other complications during pregnancy that can be fatal.

The studies’ authors partially attributed the discrepancy to previous medical guidelines that suggested that a higher rate of hypertension and anemia in the general Black U.S. population should be factored into treatment decisions.

The researchers also note implicit bias in the medical community that shows that Black patients receive better health outcomes when treated by a Black health care professional, arguing that doctors monitoring these diseases and listening to their patients is one solution to persistent inequities.

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Medical guidelines for iron-deficiency anemia had a higher threshold for treatment for Black patients until 2021. Medical experts considered it more prevalent in the Black population without considering that environmental, rather than biological, causes were contributors to that fact.

Guidelines for treating hypertension in pregnant women cautioned against overtreatment for hypertension until 2022 because of unknown risks to the fetus, essentially creating a higher bar for treatment than was necessary.

Additionally, rather than treating hypertension equally in patients, doctors routinely ignored Black women’s experiences, justifying non-treatment because of higher rates of hypertension in the Black population in general. Like with anemia, doctors wrongly considered higher rates of hypertension intrinsic to the Black population rather than socially and environmentally driven.

Dr. Irogue Igbinosa, an instructor in obstetrics and gynecology and the lead author of the anemia research, said the previous guidelines were not justified by evidence.

“There were different cutoffs by race and ethnicity that hadn’t been demonstrated to have biological plausibility,” Igbinosa said.

The studies’ findings are significant for several reasons. They highlight the fact that these are treatable and preventable medical conditions.

“The more evidence we use to standardize our approach to prenatal care, the more we can address and dismantle the effects of implicit bias on health care delivery,” Igbinosa said. “This is something we can intervene on; it’s actionable.”

The hypertension study looked at medical and birth records for nearly 8 million people in California, Michigan, Oregon, Pennsylvania and South Carolina from 2008 to 2020.

The research showed that 5.1% of pregnant Black women had chronic hypertension during pregnancy, while the general population had it at a rate of 2.1%. White pregnant women had it at a rate of 2%.

Patients with chronic hypertension developed preeclampsia, a condition that causes seizures, at 10 times the rate as those without it. Several other serious birth complications increased in prevalence as well, including acute kidney failure and pulmonary edema.

The study noted that California has enacted programs like the Maternal Quality Care Collaborative and the Perinatal Equity Initiative to try to address such inequities in health care but still is not achieving its goal of closing the racial gap in birth complications.

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“Clearly, just focusing on the bigger picture of birth complications and maternal mortality is not enough. We have to understand what drives the inequalities and tailor our interventions to them,” said Stephanie Leonard, an assistant professor of obstetrics and gynecology who led the study on hypertension.

The anemia study examined 4 million births just in California.

Pregnant women with iron-deficiency anemia were at a significantly higher risk of severe birth defects, the study found. About 21.6% of pregnant Black women had iron-deficiency anemia, while white pregnant women had it at an average of 9.6%.

Anemia was responsible for about 20% of all birth complications, according to the study.

Pregnancy can deplete a woman’s iron stores and is a common problem around the world, according to Stanford. But the study found that all other racial groups in the U.S. had worse outcomes than white patients, which the study’s author attributed to a lack of monitoring and adequate treatment in the health care system among non-white patients.

The studies’ authors conclude that unequal medical outcomes are the result of different treatment directives for different races.

They stress the need for more information from Black pregnant women about what their doctors are telling them during prenatal care.

“We need to understand more at the population level: What is your access to healthy nutrition in pregnancy? Were you told of your anemia diagnosis and provided general information of anemia in pregnancy? What have you been offered?” Igbinosa said.

“Anemia is preventable and treatable, and I think talking to communities that are disproportionately impacted by anemia is integral to providing solutions.”

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