Preterm prelabor rupture of membranes (PPROM) is defined as the rupture of the fetal membranes prior to the onset of labor and before 37 weeks of gestation; it occurs in approximately 2-3% of all pregnancies and accounts for a significant proportion of preterm births .

Current data indicate that PPROM is not merely a clinical condition limited to membrane rupture; rather, it is a biological process associated with loss of structural integrity in the fetal membranes, an inflammatory-oxidative stress response, and cellular aging . The fetal membranes constitute a dynamic barrier that provides mechanical and immunological protection for the fetus throughout pregnancy .

There is limited data in the literature investigating the relationship between osteopontin and preterm birth. In particular, it has been reported that osteopontin levels may be higher in amniotic fluid samples collected during the second trimester from pregnant women who subsequently experienced spontaneous preterm birth . However, the changes in maternal serum osteopontin levels in cases of PPROM and the clinical significance of these changes remain unclear. Therefore, osteopontin levels may vary across different biological compartments and at different stages of pregnancy. To address this knowledge gap, the present study aimed to compare maternal serum osteopontin levels between pregnant women diagnosed with PPROM and those with term membrane rupture.

This study was designed as a single-center, prospective, observational case-control study. The study protocol was approved by the Ethics Committee of the Faculty of Social and Humanities, Faculty of Science, Engineering, and Health Sciences at Batman University (Decision No: 2026/04-09; Date: 02.04.2026). Work began after the ethics committee approved the study. The research was conducted in accordance with the principles of the Declaration of Helsinki, and written informed consent was obtained from all participants.

Inclusion Criteria:

• For the case group (PPROM):
• Gestational age between 24+0 and 36+6 weeks
• Singleton pregnancy
• Age ≥18 years
• Provision of written informed consent
• Confirmed diagnosis of PPROM by clinical and/or ancillary tests
• For the control group (term rupture of membranes):
• Gestational age ≥37+0 weeks
• Rupture of membranes
• No signs of active infection
• Singleton pregnancy
• Age ≥18 years
• Provision of written informed consent
• No history of additional systemic diseases

Exclusion Criteria (for both groups):

• Multiple pregnancy
• Major fetal anomaly
• Fetal distress
• Intrauterine growth restriction (IUGR)
• Clinical chorioamnionitis
• Systemic infection
• Autoimmune or chronic inflammatory disease
• Smoking
• History of malignancy
• Gestational trophoblastic disease
• Diabetes mellitus
• Preeclampsia
• Other serious obstetric complications

Pregnant women

Case Group (PPROM): Women were eligible for the PPROM group if they met all the following criteria: confirmed diagnosis of PPROM by clinical and/or ancillary tests, gestational age between 24+0 and 36+6 weeks, singleton pregnancy, age 18 years or older, and provision of written informed consent.

Control Group (Term ROM): Women were included in the control group if they met all the following criteria: rupture of membranes at term (gestational age ≥37+0 weeks), singleton pregnancy, age 18 years or older, provision of written informed consent, absence of signs of active infection, and no history of additional systemic diseases.

IPD will not be shared as participants consented solely to the use of their data for journal publication, not to broader individual-level data sharing."