Effect of hypertensive disorders of pregnancy on outcome and relative telomere length in preterm infants.

backgroundHypertensive disorders of pregnancy(HDP) are common obstetric complications linked to adverse neonatal outcomes. Telomere length(TL) is a biomarker of cellular aging and long-term health. This study aimed to investigate the impact of HDP on preterm infant outcomes and relative TL, and to determine independent associations using multivariable adjustment.

methodsA total of 79 preterm infants born between January 2022 and December 2023 were included.The included subjects were divided into the hypertensive disorders of pregnancy(HDP) group (n = 29) and the no-hypertensive disorders of pregnancy(NHDP) group (n = 50) based on whether the mother has HDP. The general characteristics and outcomes of preterm infant were collected from electronic patient record. The TL was measured from infant umbilical cord blood using quantitative PCR. The general characteristics include gestational age, father’s age, mother’s age, number of pregnancies, number of deliveries, and gender. The outcomes include cesarean section rate, brain injury, sepsis, heart malformations, neonatal respiratory distress syndrome (NRDS), hypoxic-ischemic encephalopathy (HIE) and birth weight. Statistical analyses were conducted using SPSS 29.0 and GraphPad Prism 10, with P < 0.05 considered statistically significant.

resultsAll general characteristics (gestational age, maternal age, father’s age, number of pregnancies, number of deliveries, neonatal gender, all P > 0.05) showed no statistically difference. The rate of cesarean Sect. (100% VS 74.0%, P<0.001), sepsis (44.8% VS 22.0%, P = 0.031) and NRDS (82.6% VS 46.0%, P = 0.006) in the HDP group of preterm infants was higher than that in the NHDP group; The birth weight of the HDP group was lower than that of the NHDP group (1.63 ± 0.52 VS 2.19 ± 0.81, P<0.001), and the difference was statistically significant; There was no statistically difference in the incidence of brain injury, heart malformations and HIE between the two groups of preterm infants. The TL in the HDP group was shorter than that in the NHDP group (1.766 ± 0.673 VS 2.296 ± 0.728, P = 0.002) and the difference was statistically significant ; in male preterm infants and female preterm infants, the TL in the HDP group was shorter than that in the NHDP group, and the difference was statistically significant (1.658 ± 0.721 vs. 2.199 ± 0.695, P = 0.019 ; 1.867 ± 0.633 vs. 2.501 ± 0.776, P = 0.021) ; in the HDP group and the NHDP group, no differences in TL were found between preterm infants of different genders. Logistic regression analysis showed that the HDP has a statistically significant impact on NRDS ( OR = 3.788, 95% CI : 1.121–12.805, P = 0.032 ) and sepsis ( OR = 3.376, 95% CI : 1.067–10.681, P = 0.038 ). Gestational age was associated with a decreased risk of NRDS (OR = 0.694, 95%CI: 0.566–0.852, P<0.001). Multivariate linear regression show that there is a statistically significant correlation between HDP and the decrease in birth weight (β = -0.263, P < 0.001), while gestational weeks have a statistically significant correlation with the increase in birth weight (β = 0.844, P < 0.001). HDP is statistically associated with shortened TL (β=-0.361, P<0.001) and neonatal gender (male) is statistically associated with shortened TL (β=-0.251, P = 0.022).

conclusionHDP is associated with higher cesarean section rate, elevated incidence of NRDS and sepsis, lower birth weight, and shorter relative TL in preterm infants. HDP is independently associated with increased risks of NRDS and sepsis; increasing gestational age is associated with reduced risk of NRDS. Multivariate analysis confirmed that HDP is independently associated with lower birth weight and shorter TL, and male sex is also associated with shorter TL.