# Association between maternal cervical Ureaplasma urealyticum colonization and adverse perinatal outcomes: a prospective multicenter cohort study

## TL;DR

This study found that high levels of Ureaplasma urealyticum in pregnant women's cervixes are linked to a higher risk of early preterm birth and complications in preterm infants.

## Contribution

The study identifies Ureaplasma urealyticum load as an independent risk factor for preterm birth before 32 weeks of gestation.

## Key findings

- Women with Ureaplasma urealyticum load ≥10⁵ copies/mL had higher rates of spontaneous preterm birth and neonatal death.
- Uu load ≥10⁵ copies/mL was an independent risk factor for preterm birth before 32 weeks (OR 5.653).
- Preterm infants from Uu-positive mothers had higher discontinuation rates of life-sustaining therapy.

## Abstract

The association between maternal cervical Ureaplasma urealyticum (Uu) colonization and adverse perinatal outcomes remains controversial. This study aimed to investigate the relationship between maternal cervical Uu colonization, Uu load during mid-pregnancy, and perinatal outcomes, with a focus on complications in preterm infants.

This prospective multicenter cohort study was conducted between July 2021 and January 2024 at four tertiary-level maternity and children’s hospitals in Zhejiang Province, China. Pregnant women with ultrasound-confirmed gestational age of 20+ 0 to 24+ 6 weeks were enrolled, and cervical Uu colonization was assessed by polymerase chain reaction (PCR). Pregnancy outcomes, including spontaneous preterm birth, pregnancy loss, and neonatal complications, were systematically recorded and analyzed.

Among 452 enrolled participants in this prospective multicenter study, 243 (42.5%) tested positive for Uu colonization. The median Uu DNA load among Uu-positive pregnant women was 1.46 × 105copies/ml. The rate of discontinuation of life-sustaining therapy among preterm infants born at 23–25 weeks of gestation was significantly higher in the Uu-positive group compared to the Uu-negative group (3.7% vs. 0.5%, P = 0.045). Women with high Uu load (≥ 10⁵ copies/mL) had significantly increased rates of spontaneous preterm birth before 32 weeks, spontaneous preterm birth before 28 weeks, premature rupture of membranes (PROM), and neonatal death, compared to those with low or no colonization (P < 0.05). Multivariate analysis identified Uu load ≥ 10⁵ copies/mL as an independent risk factor for preterm birth before 32 weeks of gestation, with an OR of 5.653 (95%CI: 2.032 ~ 15.727).

Maternal cervical Uu load ≥10⁵ copies/mL may be associated with increased risk of spontaneous preterm birth before 32 weeks.

The research protocol was registered in the Chinese Clinical Trial Registry (No. ChiCTR2100044524) on 10 March 2021.

The online version contains supplementary material available at 10.1186/s12884-026-08839-2.