Coverage with private insurance was associated with a lower infant mortality rate (IMR) and lower risk of adverse outcomes compared with public Medicaid insurance in a recent study of more than 13 million infants. The findings, published in JAMA Network Open, suggest there are opportunities to improve care access, quality, and outcomes in Medicaid-insured pregnancies.1
Health insurance status is known to be associated with health care access and health outcomes, and the authors of the study aimed to determine whether maternal private insurance is associated with a lower IMR compared with public Medicaid insurance in the United States.
“IMRs in the US are among the highest in the developed world at least in part because of a combination of racial, regional, and socioeconomic disparities,” the authors wrote. “The IMR is also substantially affected by high rates of preterm birth, which, in turn, may be affected by differences in the reporting of live births at the lowest gestations, and higher gestational age–specific IMRs within the US.”
Medicaid—which covers care for pregnancy, perinatal, postpartum, and infant care for those with a family income within 138% of the federal poverty level—covered 42.1% of all births in the United States in 2019.2 But in some states, the authors noted, pregnant individuals must complete an application process and are not automatically made beneficiaries following conception.
“It is possible that this process may result in higher rates of inadequate or delayed prenatal care, which is known to be associated with adverse infant outcomes,” the authors wrote.
The cohort study utilized data from 2017 to 2020 in the CDC Wide-Ranging Online Data for Epidemiologic Research expanded linked birth and infant death records database. Infants born in the hospital from 20 to 42 weeks of gestational age and whose mothers had either private or Medicaid insurance were included in the study, with the primary outcome being IMR in both insurance groups.
A total of 13,562,625 infants were included in the study, and a negative-binomial regression was done to adjust for race, sex, multiple birth, CDC-defined maternal pregnancy risk factors, education level, and tobacco use when assessing the difference in IMR between private and Medicaid-insured pregnancies. Differences in categorical variables between groups were compared using the χ2 or Fisher exact test.
Of the infants included in the cohort, 7,327,339 mothers (54.0%) had private insurance and 6,235,286 (46.0%) had Medicaid. The IMR was lower among infants born to mothers with private insurance (2.75 deaths per 1000 live births) compared with infants born to mothers with Medicaid (5.30 deaths per 1000 live births), with an adjusted relative risk (aRR) of 0.81 (95% CI, 0.69-0.95; P = .009).
Postneonatal mortality risk was also lower among those with private insurance compared with Medicaid (0.81 vs 2.41 deaths per 1000 births [aRR, 0.57; 95% CI, 0.47-0.68; P < .001]). The risks of low birth weight and vaginal breech delivery were also lower in those with private insurance, with aRRs of 0.90 (95% CI, 0.85-0.94; P < .001) and 0.80 (95% CI, 0.67-0.96; P = .02), respectively. The same trend was seen in the risk of preterm birth (aRR, 0.92; 95% CI, 0.88-0.97; P = .002).
Regarding early pregnancy care, those with private insurance also had a higher probability of receiving first trimester prenatal care compared with Medicaid-insured mothers, with an aRR of 1.24 (95% CI, 1.21-1.27; P < .001).
There were no significant differences between rates of maternal morbidity, extremely preterm birth, extremely low birth weight, or antenatal corticosteroid use between insurance types.
The findings support those of smaller or older studies assessing insurance status and infant outcomes, the authors noted. The study was limited by a lack of individual-level data despite its large cohort, as well as the exclusion infants born outside of a hospital and those with congenital anomalies, although the authors noted that the effect on bias is likely small due to the relatively low number of infants falling into those subgroups.
“In this cohort study, maternal private health insurance was associated with a lower IMR compared with Medicaid health insurance. In addition, privately insured pregnancies had higher rates of early prenatal care and fewer preterm and low birth weight births. There are opportunities to improve access to care and pregnancy outcomes among Medicaid insured pregnancies in the US,” the authors concluded.
1. Johnson DL, Carlo WA, Rahman AKM, et al. Health insurance and differences in infant mortality rates in the US. JAMA Netw Open. 2023;6(10):e2337690. doi:10.1001/jamanetworkopen.2023.37690
2. Martin JA, Hamilton BE, Osterman MJK, Driscoll AK. Births: final data for 2019. Natl Vital Stat Rep. 2021;70(2):1-51.