The Effect of Non-Stress Test Results on Perinatal Outcomes in Expectantly Managed Pregnancies Complicated by Premature Rupture of Membranes

Aim: This study aimed to evaluate the impact of nonstress test (NST) findings on perinatal outcomes in pregnancies complicated by premature rupture of membranes (PROM) managed expectantly.Materials and Methods: This retrospective study included pregnant women with preterm premature rupture of membranes (PPROM) between 26 and 34 weeks of gestation who were admitted to Konya City Hospital from January 2018 to January 2024.Patient data, including gestational age, maternal age, gravidity, parity, and comorbidities, were analyzed. NST results were classified into three categories based on the NICHD 2008 guidelines. A total of 96 patients were included in the study. Among them, 68 were classified as NST Category 1, 4 as NST Category 2, and 24 as NST Category 3. Since only four cases were identified in Category 2, this group was excluded from the analyses due to the inability to achieve statistical significance. Therefore, comparisons were conducted solely between Category 1 (n=68) and Category 3 (n=24) groups. Cases with abnormal Doppler findings, fetal anomalies, or intrauterine growth restriction were excluded. Perinatal outcomes were evaluated by recording birth weights, blood gas parameters, Apgar scores, NICU admission rates, NICU stay duration, and neonatal mortality rates.Results: In our study, the parameters that demonstrated statistically significant differences in blood gas analysis were pH and base excess. The pH was 7.36 in Category 1 and 7.30 in Category 3 (p =0.003), while base excess was found to be significantly lower in Category 3 compared to Category 1 (-3.90 vs. -2.27; p = 0.028). The mean 1-minute Apgar scores were 7.64 for Category 1 and 7.33 for Category 3 (p = 0.253), while the mean 5-minute scores were 8.72 and 8.45, respectively (p = 0.306). There were 3 neonatal deaths (4.4%) in Category 1 and 1 death (4.2%) in Category 3; no significant difference was observed. NICU admission rates were 58.8% for Category 1 and 66.7% for Category 3.Conclusion: Although NST is a useful method for assessing fetal well-being, its ability to predict perinatal outcomes in PPROM cases is limited. Since basing delivery decisions solely on NST findings may lead to unnecessary preterm births, clinical evaluation should be comprehensive and multidisciplinary. In pregnancies complicated by PPROM, an individualized management strategy should be adopted, and further studies are warranted to validate these findings.