Racial and ethnic disparities in maternal health outcomes are pronounced and persistent in the United States, and—to some extent—remain unexplained, according to Alecia J. McGregor, PhD. “In particular, New Jersey has some of the country’s worst outcomes when it comes to maternal health,” Dr. McGregor says. “Although it is among the wealthiest states in the country, it ranks among the five US states with the highest maternal mortality rates (MMRs). In 2019, it reported the highest Black MMR of all states reporting this data.”

New Jersey, Dr. McGregor points out, has also seen rapid closures of hospitals in recent decades, including a dramatic decrease in obstetric (OB) units. “Between 2006 and 2015, more than 20% of the state’s OB units closed or relocated. Therefore, we wanted to explore how OB unit closures in general impact the alarming maternal health disparities observed in the state.”

Severe Maternal Morbidity Twice as Common in Blacks

For a paper published in the American Journal of Obstetrics & Gynecology MFM, Dr. McGregor and colleagues sought to examine racial differences in severe maternal morbidity (SMM) in New Jersey hospitals among women experiencing the loss of the nearest OB unit from 2006-2015. “Although the MMR in the US is the highest of any developed country, maternal mortality is still a relatively rare event,” she says. “SMM (or life-threatening illnesses that can occur during or after delivery) is much more common, and Black women are more than twice as likely to suffer from SMM than their White counterparts. Studying SMM rates can provide greater insights into drivers of high MMR rates and disparities in SMM and MMR.”

The researchers used inpatient discharge data and identified all childbirth hospitalizations between 2006 and 2015 in New Jersey. They merged this data with hospital-level data, including information on where OB units closed in the state, and linked zip code level demographic data. Statistical analyses were then conducted to estimate the effect of giving birth on rates of SMM after closure of the nearest OB unit.

McGregor and colleagues reported 227,412 delivery hospitalizations among women who lived in the 124 New Jersey zip code tabulation areas that lost the nearest OB unit between 2006 and 2015. “We found that Black women had the highest SMM rates, increasing from 1.2% in 2006 to 2.3% in 2015,” Dr. McGregor says. “The Black-White gap remained similar in magnitude during this period, as White women’s SMM rates rose from 0.7% to 1.4%. Among Hispanic women, SMM increased considerably, from 0.7% in 2006 to 2.4% in 2013, followed by a declining trend from 2013-2015. For all women, delivery in a Black-serving OB unit correlated with an increased likelihood of individual SMM.”

Latina Women Especially at Risk

Not all OB units are created equally, Dr. McGregor points out, and Black-serving hospitals are systematically underfunded and lack the capital investments found in predominately White hospitals. “Across the country, there is a de facto segregation in where pregnant patients deliver their babies. In our sample of New Jersey hospitals, there were hospitals where no Black patients delivered, as well as hospitals where no White patients delivered. This is staggering considering the diverse racial and ethnic composition of New Jersey. In addition, we found that the risk of SMM for Latina women was worse, over time, than for other groups. The risk of adverse outcomes was also greater for Latia women when they delivered in high birth volume hospitals (Table).”

The study team concurs that, on a national level, it is critical for OB/GYNs to recognize the differential risks that come with delivering babies, especially in neighborhoods lacking access to OB care. “OB/GYNs should play a role in advocating for sufficient resources for their patient populations, particularly if they primarily serve people of color,” Dr. McGregor notes.

“Further research is needed to explore why outcomes for Latina women worsened more dramatically over time compared to other groups in our study,” she concludes. “Furthermore, policymakers should take steps to prevent OB unit closures and to ensure that the resources available at Black-serving OBs are at least on par with those of other institutions.”