Background This cross-sectional study aims to identify the relationship between perceived stress, social support and sleep quality and the effects of the COVID-19 pandemic on pregnant women’s perceived stress, social support and sleep quality.

Methods The target population of the study was pregnant women who applied to the Family Health Center. After the sample calculation was performed, the study involved 166 participants. The data, which were quantitative in nature, were collected through a web-based, online questionnaire administered within a determined period. Data collection tools included the Multidimensional Scale of Perceived Social Support (MSPSS), the Perceived Stress Scale (PSS), and the Pittsburgh Sleep Quality Index (PSQI).

Results Of all the participating pregnant women, 88% reported to have poor sleep quality during the COVID-19 pandemic. A moderate, negative relationship was found between the Pittsburgh Sleep Quality Index and the Multidimensional Scale of Perceived Social Support and a weak, positive relationship with the Perceived Stress Scale. While statistically significant differences were found between the pregnant women’s perceived stress according to their psychological perceptions and perceptions about daily life (P < 0.05), no significant differences were found between the perceived social support level and sleep quality index.

Conclusion It was considered that pregnant women’s perceived social support levels, sleep quality, and perceived stress levels were affected during the COVID-19 pandemic.