Background: Pregnancy is one of the most sensitive stages of a woman's life, and changes at this time can have physical and psychological complications for women. Objectives: This study aimed to assess the frequency of pregnancy complaints (PC) and the effective socio-demographic factors among pregnant women referred to Neyshabur health centers. Methods: This cross-sectional study was performed on 417 pregnant women referred to Neyshabur health centers in 2021. Data collection was carried out using demographic characteristics and PC questionnaires. Descriptive statistics (mean, standard deviation), analytical statistics (multiple linear regression). The software used for data analysis was SPSS software version 22. The significance level was considered at 0.05. Results: The mean age of pregnant women was 28.36 ± 5.96. The mean PC score was 37.76 ± 8.85. Fatigue (73.38%) and hemorrhoids (4.8%) were the most common and least common PC. Multiple linear regression results showed that maternal age (P < 0.05) and sleep quality (P < 0.001) were statistically significant variables related to PC. On this basis, as maternal age increases, the mean score for PC increases by 0.94. In addition, the average score of pregnancy-related complaints for those with a good quality of sleep was 6.32 lower than for those with a bad quality of sleep. Conclusions: Maternal age and bad sleep quality factors increase the possibility of a pregnancy-related complaint. So, it is recommended that healthcare providers develop and implement educational interventions to improve sleep quality and pregnancy awareness at older ages.