# Prevalence, perinatal risk factors and clinical outcomes of respiratory Ureaplasma species colonization in hospitalized preterm infants

## TL;DR

This study finds that Ureaplasma colonization is common in preterm infants and is linked to several serious health issues like lung and eye problems.

## Contribution

The study identifies Ureaplasma colonization as an independent risk factor for bronchopulmonary dysplasia, necrotizing enterocolitis, and retinopathy of prematurity in preterm infants.

## Key findings

- Ureaplasma colonization was found in 15.8% of preterm infants, increasing with lower gestational age.
- Colonization was associated with higher rates of bronchopulmonary dysplasia, necrotizing enterocolitis, and retinopathy of prematurity.
- Vaginal delivery and prolonged rupture of membranes were significant risk factors for Ureaplasma colonization.

## Abstract

To investigate the prevalence, perinatal risk factors, and clinical outcomes associated with Ureaplasma species (Ureaplasma spp.) colonization in hospitalized preterm infants.

This retrospective study included preterm infants (<37 weeks’ gestation) admitted to the Neonatology Department of the Children's Hospital of Soochow University, China, between December 2023 and June 2025. Infants transferred within 72 h of birth and tested for Ureaplasma spp. in nasopharyngeal aspirates within 72 h were eligible. Infants with delayed testing, incomplete clinical data, or early death or discharge were excluded. Nasopharyngeal aspirates samples were analyzed for Ureaplasma spp. DNA by polymerase chain reaction. Demographic, perinatal, laboratory, and clinical outcome data were collected. Comparisons between Ureaplasma spp.-positive and Ureaplasma spp.-negative groups were performed, and multivariate logistic regression was used to evaluate the association between Ureaplasma spp. colonization and major morbidities.

Among 368 eligible preterm infants, 58 (15.8%) were Ureaplasma spp.-positive. The colonization rate increased progressively with decreasing gestational age (GA), reaching 31.8% among infants <28 weeks, and was highest among those with a birth weight of 1,000–1,499 g (20.4%). Ureaplasma spp.-positive infants had a significantly lower GA (P < 0.05). Vaginal delivery and prolonged rupture of membranes (PROM) were more common in the Ureaplasma spp.-positive group (both P < 0.001), whereas gestational hypertension was more frequent in the negative group (P = 0.008). The positive group had higher white blood cell counts and a greater frequency of elevated C-reactive protein (CRP) levels (P < 0.05). Clinically, Ureaplasma spp. colonization was associated with more frequent and prolonged oxygen supplementation and higher incidences of bronchopulmonary dysplasia (BPD), necrotizing enterocolitis (NEC), sepsis, and retinopathy of prematurity (ROP) (all P < 0.05). After adjusting for confounders, Ureaplasma spp. colonization remained independently associated with BPD, NEC, and ROP (P < 0.05), but not with sepsis.

Ureaplasma spp. colonization is common in hospitalized preterm infants, particularly among those of lower gestational age. Vaginal delivery and PROM are significant perinatal risk factors. Ureaplasma spp. colonization is associated with heightened inflammatory responses and independently contributes to major morbidities, including BPD, NEC, and ROP, but not with sepsis after adjustment for confounders.