407 - Morbidities and Mortality of Twin and Triplet Infants Compared to Singleton Infants Born After 32 Weeks’ Gestation

Poster Number: 407
Publication Number: 407.135

Sara Khan, Seattle Children's, Seattle, WA, United States; Rachel G. Greenberg, Duke Clinical Research Institute, Durham, NC, United States; Ryan Kilpatrick, Duke University School of Medicine, Durham, NC, United States; Reese H. Clark, MEDNAX, Myrtle Beach, SC, United States; Sarah E. Kolnik, University of Washington School of Medicine, Seattle, WA, United States; Mihai Puia-Dumitrescu, University of Washington School of Medicine, Seattle, WA, United States

Background: Multi-gestation pregnancies account for 3% of all live US births. Recent and accurate data of twin and triplet outcomes compared to singletons are necessary to understand how advances in neonatal intensive care over the past two decades have affected outcomes and ensure proper counseling of obstetric patients with multi-gestation pregnancies. 

Objective: To describe and compare in-hospital morbidities and mortality among twins and triplets born after ≥ 32 weeks gestational age (GA) to age-equivalent singleton counterparts.

Design/Methods: We performed a multicenter cohort study of inborn singleton, twin, and triplet infants with ≥ 32 weeks GA without major congenital anomalies who were discharged from a neonatal intensive care unit (NICU) managed by the Pediatrix Medical Group between 2010 and 2018. We evaluated the prevalence of twin and triplet admissions across sites and compared demographics, clinical characteristics, and in-hospital morbidities and mortality among groups.

Results: Of 799,016 infants born in 361 Pediatrix-managed NICUs, 547,488 met study inclusion criteria and 56% were male. There was wide variability (0 to 33%) in the rates of twin and triplet NICU admissions among sites (Figure 1). Overall, median (25th, 75th percentile) birthweight (BW) was 2790 (2205, 3380) grams and GA was 37 (34, 39) weeks, with triplets and twins having lower GA, lower BW and more likely to be small for gestational age and be delivered via C-section (Table 1). Singleton infants were more likely to die prior to discharge compared to twins and triplets and morbidities were more commonly seen in multiples (Table 2). Hyperbilirubinemia requiring phototherapy was more common in multiples (27%) with triplets having the highest rates (43%). Pneumothorax and seizures were rare overall ( < 1%) and more commonly seen in singletons (p < 0.001). Median (IQR) length of stay was directly related to order of gestation and was 8 (5, 14) days vs 15 (10, 22) days vs 20 (14, 27) days for singletons, twins and triplets respectively (p < 0.001).Conclusion(s): In this large cohort of infants ≥32 weeks GA, the proportion of twin and triplet infants making up the total admissions to NICUs varied substantially among centers. Twins and triplets were more likely to have earlier gestational age, lower birth weight, and to develop neonatal morbidities.
Figure 1: Percentage of twin and triplet births at each of 361 included study sites
Table 1: Maternal and neonatal baseline characteristics*NIV non-invasive ventilation = hood oxygen, low flow nasal cannula
**NIPPV non-invasive positive pressure ventilation = high flow nasal cannula, CPAP, nasal intermittent mandatory ventilation
*** p < 0.001 when compared to singletons