Introduction: Pregnancy-related hormonal and vascular changes may increase nasal mucosal congestion, particularly during the third trimester, when sleep disturbance is also common. Nasal obstruction can promote mouth breathing, nocturnal discomfort, and fragmented sleep. This study aimed to evaluate the effect of NOSE score on sleep quality in primigravid women during the third trimester of pregnancy.

Material and methods: This descriptive cross-sectional study will be conducted at Tabriz University of Medical Sciences in 2026 on 66 primigravid women in the third trimester of pregnancy, selected by convenience sampling. The main variables will include demographic and obstetric characteristics, NOSE score, sleep quality indices, and pregnancy-related sleep disruptors such as nocturia, reflux, back pain, fetal movement-related awakening, and nocturnal breathing discomfort.

Results: Among 66 primigravid women, poor sleep quality was associated with significantly higher NOSE scores than good sleep quality (56.84 ± 18.27 vs. 31.46 ± 14.92, p < 0.001), with severe nasal obstruction occurring more often in poor sleepers (39.47% vs. 10.71%, p = 0.012). NOSE score correlated with worse sleep quality (r = 0.58, p < 0.001) and remained an independent predictor in adjusted analysis (B = 0.07, p = 0.001).

Conclusion: Poor sleep quality in third-trimester primigravid women was significantly associated with greater nasal obstruction severity. Higher NOSE scores independently predicted worse sleep quality, suggesting that nasal symptoms may represent an important and potentially modifiable contributor to sleep disturbance during late pregnancy.