Evaluating Risk-Adjusted Associations between Prenatal Care Utilization and Obstetric Outcomes in a Commercially Insured Patient Population

Office prenatal care has followed a similar structure for the past century. It is largely unknown whether attendance at routine outpatient antenatal visits prevents major adverse maternal outcomes. This study examined associations between prenatal care utilization and adverse obstetric outcomes including severe maternal morbidity (SMM), preterm birth, and stillbirth in a large, commercially insured US patient population.This is a retrospective cohort study using an insurance claims database evaluating associations between prenatal care utilization and obstetric outcomes over 4 years (2017-2020). Prenatal care utilization was characterized based on the adequacy of prenatal care utilization (APNCU) index. The primary outcome was SMM (as per Centers for Disease Control). Secondary outcomes included preterm birth <37 weeks and stillbirth. Associations between exposure and outcome were investigated using logistic regression models in designated "low" and "medium" maternal risk groups, defined based on obstetric co-morbidity index (OB-CMI) scores modeled at the time of the first trimester and at delivery.A total of 297,453 patients were included: 78,100 in the sub-group who remained low-risk throughout pregnancy and 49,920 in the sub-group who remained medium-risk. The largest number of patients overall (29.9%) received "adequate plus" care, as defined by the APNCU index, while a plurality of low- and medium-risk patients received "intermediate" care (35.6 and 29.9%, respectively). One point seventy seven percent of patients experienced SMM, 8.63% delivered preterm, and 0.88% had stillbirth. Adjusted analysis comparing volume of prenatal care with these outcomes demonstrated no statistically significant associations, with the exception of preterm birth, which was positively associated with "adequate" and "adequate plus" care in low- and medium-risk patients. "Inadequate care" was not associated with any of the studied outcomes.Overall volume of prenatal care was not associated with a reduction in adverse obstetric outcomes. Clinical quality improvement and health policy efforts to improve prenatal care delivery models may need to bypass adherence to established guidelines in terms of gross visit number as a key metric and instead work to revise practices based on more meaningful clinical outcomes. · It is unknown whether receipt of routine prenatal care is associated with better pregnancy outcomes.. · There were no associations between amount of prenatal care and SMM or stillbirth.. · Preterm birth was associated with "adequate" and "adequate plus" care in low- and medium-risk patients.. · Likely suggesting higher utilization in the setting of concerning symptoms.. · "Inadequate" care was not associated with any of the studied adverse outcomes..