The effects of latency period in PPROM cases managed expectantly

Abstract

Objective: Preterm premature rupture of membranes (PPROM), associated with prematurity, is an important obstetric complication that may cause neonatal mortality and morbidity. The optimal delivery time is controversial in cases with the expectant approach. The fetal effects of long-term exposure to PPROM are unknown. This study aimed to evaluate the maternal and fetal outcomes of expectantly-managed PPROM cases with different latency periods at 24^0/7-34^6/7 weeks of gestation.Material and method: The study group consisted of 206 patients at 24^0/7-34^6/7 weeks of gestation who met the inclusion criteria. Patients were divided into three groups according to their weeks of PPROM diagnosis as 24^0/7-28^6/7, 29^0/7-31^6/7, and 32^0/7-34^6/7. The period from membrane rupture to delivery was defined as the latency period and divided into three subgroups as 3-7 days, 8-13 days and ≥14 days. In addition to the demographic characteristics of the patients, maternal and obstetric complications, primary and secondary neonatal outcomes were compared between the groups. Primary neonatal outcomes were determined in terms of pathological Apgar scores (<5 at minute 1, <7 at minute 5), requiring resuscitation, admission to Neonatal Intensive Care Unit (NICU) and NICU length of stay. Secondary neonatal outcomes were determined in terms of respiratory distress syndrome, bronchopulmonary dysplasia, intraventricular hemorrhage, retinopathy of prematurity, necrotizing enterocolitis, patent ductus arteriosus, periventricular leukomalacia, and neonatal sepsis. In addition, for the prediction of morbidity and mortality, newborns were evaluated by SNAPPE II (Score for Neonatal Acute Physiology with Perinatal extension-II) consisting of the combination of biochemical and physiological parameters, using the parameters including mean blood pressure (mm/Hg), corporal temperature (°C), PO₂/FiO₂ ratio, lowest serum pH, multiple seizures, urine output (ml/kg/hr), Apgar score, birth weight, and small for gestational age. The higher the score of SNAPPE II, the higher the morbidity and mortality risk of neonates. For the statistical analysis, the Kruskal Wallis and one-way ANOVA tests were utilized for the numerical data. Categorical data were compared using the chi-square test. The receiver operating characteristic (ROC) test was used to determine the threshold value of the data affecting neonatal morbidity.Results: The mean PPROM week was found to be 29.7 ± 3.0 weeks and the mean delivery week was 31.8 ± 2.5 weeks. The mean latency period for all the patients was 15.1 ± 13.8 days. Clinic chorioamnionitis was observed in 17% of the cases. The lowest chorioamnionitis rate (8.6%) was in the 3-7-day latency period group. Total complications were significantly lower in the 29^0/7-31^6/7 week PPROM group in which the latency period was ≥14 days, compared to those in 3-7 days and 8-13 days (p = .001). Total complications were lower in the < 32 weeks PPROM groups in which the latency period was ≥14 days compared to those obtained in 3-7 days and 8-13 days. There was no significant difference between the latency period and total complications after 32 weeks (p = .422). The best discriminative cutoff value of SNAPPE-II for neonatal morbidity was 11.0 (sensitivity 82%, specificity 80%). In the present study, the optimal latency period for the best neonatal outcomes was found to be 34.5 days (sensitivity 70% and specificity 84%) between weeks 24^0/7-28^6/7, and 11.0 days between weeks 29^0/7-31^6/7 (sensitivity 68% and specificity 85%).Conclusions: Our findings indicated that a long latency period did not increase neonatal morbidity and there was no increase in neonatal complications after 32 weeks of the gestational period compared to those obtained before 32 weeks.

Keywords: Expectant management; latency; neonatal outcome; pregnancy; preterm birth; preterm premature rupture of membranes.