(237) Infant Growth and Development Outcomes among Commercially Insured Infants in the United States, 2016 – 2023

Background: Infant growth and development (IGD) outcomes, particularly during the first year of life, are of increasing interest in studies of medication safety during pregnancy. Capture of IGD codes in administrative claims data has not been previously reported.

Objectives: To describe the prevalence and characteristics of IGD codes among a large cohort of commercially-insured pregnancies resulting in liveborn infants.

Methods: This study used data from Optum’s Dynamic Assessment of Pregnancies and Infants (DAPI), a proprietary process that identifies pregnancies and mother-infant linkages within the Optum Research Database, a health insurance claims data source. Infants were eligible for inclusion if they were linked to a pregnancy with an estimated last menstrual period (LMP) between 01 January 2016 and 31 December 2022, and were enrolled in the health plan during their first month of life. IGD was classified as either postnatal growth deficiency (PGD) or infant developmental delay (IDD), and outcomes were identified via International Classification of Disease, 10th Revision (ICD-10) codes. Characteristics were assessed for infants overall and among those with an IGD code during the first year of life.

Results: Between 2016 and 2023, a total of 626,223 liveborn infants were identified in the Optum DAPI data. Of these, 69,983 (11.2%) infants had a PGD code and 60,842 (9.7%) had an IDD code during the first year of life. Compared to all livebirths, infants with IGD codes were more likely to be born to older individuals (mean age at LMP: 31.0 years for all infants vs. 31.4 and 31.5 years for PGD and IDD infants, respectively). The likelihood of having an IGD diagnosis decreased with increasing gestational age (GA) at birth: among infants born at GA ≤ 30 weeks, 35.2% had a PGD and 28.1% had an IDD diagnosis, as compared to 9.5% and 8.9% with PGD and IDD diagnoses, respectively, among infants born at GA of 40 weeks. The most common PGD codes were diagnoses for failure to thrive (42.9% of infants with PGD), followed by codes for unspecified lack of normal physiological development (11.1%) and effects of slow intrauterine growth (7.8%). The most common IDD codes were Z-codes associated with screening for developmental delays (14.8 – 36.3% of infants with IDD), followed by codes for delayed motor function (14.6%) and delayed milestones (8.7%).

Conclusions: Infant growth and development outcomes in the first year of life are increasingly of interest in studies of exposure to medications during pregnancy. Approximately 10% of infants had a claim with a diagnosis code relating to growth deficiency or developmental delays in the first year of life; however, the accuracy of these codes for identifying true cases is unknown. Future work will assess the timing of IGD codes in the first year of life and beyond.