Maternal multimorbidity linked to increased neonatal risk

Data published in JAMA Network Open highlighted increasing risks of severe neonatal morbidity or mortality (SNM-M) with a rise in the number of preexisting maternal chronic conditions.¹

Adverse outcomes linked to multiple chronic conditions (MCC) in adults include high health care costs, elevated acute care use, and premature mortality.² Additionally, increases in maternal morbidity and mortality risks have been reported in a dose-response manner with the number of chronic conditions.¹

“While maternal health has been considered in association with MCC, few studies have explored the association with infant outcomes, such as severe neonatal morbidity and mortality,” wrote investigators.

Evaluation of MCC

The population-based cohort study was conducted to evaluate the risk of SNM-M based on the number of prepregnancy chronic conditions, MCC complexity, cardiometabolic type, and severity. Women and adolescent girls aged 13 to 54 years residing in Ontario, Canada, were included in the analysis.

Additional eligibility criteria included live birth at 20-weeks’ gestation or later between April 1, 2012, and March 31, 2021. Patients without provincial health insurance during the 2 years before conception were excluded.

Investigators determined MCC based on the number of chronic conditions recorded within 2 years before conception. Sixteen chronic conditions were initially included based on their frequency and cost, with an additional 6 related to pregnancy also added for 22 total conditions.

Assessment of MCC complexity, type, and severity

Categories for the number of maternal conditions included 0, 1, 2, and 3 or more. The presence of 3 or more conditions impacting 3 or more body systems indicated complex MCC.

Cardiometabolic MCC was also reported, including congestive heart failure, chronic hypertension, cardiac arrhythmia, obesity, stroke, diabetes, and coronary artery syndrome. Severity was indicated by a nonbirth hospitalization for chronic disease during pregnancy.

SNM-M was reported as the primary outcome and included 14 diagnoses and 7 procedure codes recorded less than 28 days after discharge. Investigators also collected mortality data, and other neonatal adversity indicators were reported as secondary outcomes. Covariates included parity, maternal age, immigration status, neighborhood income quintile, and rural residence.

Dose-response association between MCC and SNM-M

There were 1,018,968 births reported, 2.1% of which were to mothers with 3 or more chronic conditions, 7.2% 2 chronic conditions, 27.2% 1 chronic condition, and 63.5% no chronic conditions. A younger age, reduced odds of being immigrants, and increased odds of rural residence were reported among mothers with MCC vs those with 0 conditions.

A dose-response increase in SNM-M risk was reported among newborns of mothers with 1, 2, or 3 or more chronic conditions vs those with 0, with adjusted relative risks (aRRs) of 1.26, 1.58, and 2.01, respectively. Additionally, the aRR was 1.97 for those with complex MCC vs 1.62 for those with noncomplex MCC, highlighting a more pronounced effect.

SNM-M risk also increased alongside the number of maternal cardiometabolic conditions. An aRR of 2.67 was reported for SNM-M among newborns of mothers with 3 or more cardiometabolic conditions vs 0. In comparison, the aRR was 1.94 among those whose mothers had 4 or more noncardiometabolic conditions.

Influence of MCC severity and clinical implications

Additionally, MCC severity influenced the risk of SNM-M. Compared to mothers with 0 conditions, an aRR of 3.11 was reported for mothers with 3 or more conditions and a prenatal hospitalization, vs 1.99 for those with 3 or more conditions but no prenatal hospitalization.

Overall, these results highlighted an association between MCC and SNM-M risk. Investigators concluded a multidisciplinary approach and a proactive plan for maternal and infant care are needed to support patients with MCC.

“Given the risks of prematurity and neonatal morbidity in women with MCC, this plan should include delivery at a hospital equipped with higher-level neonatal care and prearrangement of postdischarge home care supports,” wrote investigators.

References

1. Brown HK, Fung K, Cohen E, et al. Multiple maternal chronic conditions and risk of severe neonatal morbidity and mortality. JAMA Netw Open. 2026;9(1):e2555558. doi:10.1001/jamanetworkopen.2025.55558
2. Johnston MC, Black C, Mercer SW, Prescott GJ, Crilly MA. Prevalence of secondary care multimorbidity in mid-life and its association with premature mortality in a large longitudinal cohort study.BMJ Open. 2020;10(5):e033622. doi:10.1136/bmjopen-2019-033622