Smoking in Pregnancy: Can the first-trimester serum inflammatory markers predict adverse obstetric and neonatal outcomes?

Aim: To investigate obstetric complications in pregnant women who smoke and to evaluate whether first-trimester systemic inflammatory indices can predict adverse obstetric and neonatal outcomes Materials and Method: This retrospective study included 43 pregnant women aged between 18 and 45 years who had been smoking since prior to conception, and 44 healthy pregnant women, conducted between 2024 and 2025. Participants' demographic characteristics, obstetric outcomes (birth weight, gestational age at delivery), and neonatal outcomes (APGAR scores, NICU admission) and obstetric complications were assessed. First-trimester neutrophil-to-lymphocyte ratio (NLR), systemic immune-inflammation index (SII: NLR × platelet count), systemic inflammation response index (SIRI: NLR × monocyte count), aggregate index of systemic inflammation (AISI: NLR × platelet count × monocyte count), and platelet-to-lymphocyte ratio (PLR) were calculated. Receiver operating characteristic (ROC) curves were generated to evaluate the predictive value of these markers for adverse obstetric and neonatal outcomes. Results: SII, SIRI, AISI, and NLR levels were significantly higher in the smoking group compared to controls. Pregnant women who smoked had higher rates of emergency cesarean section, adverse obstetric outcomes, and NICU admissions. ROC analysis showed that first-trimester inflammatory markers significantly predicted adverse outcomes when all participants were analyzed together; however, these markers did not demonstrate predictive value within the smoking group alone. Conclusion: Adverse obstetric outcomes, increased NICU admissions, and elevated serum inflammatory markers were observed in pregnant women who smoked. However, these markers were found to be insufficient in predicting adverse outcomes.