Aim To examine the effect of fundal pressure applied in the second stage of labor on birth outcomes and neonatal O2 saturation. Methods The study is of a descriptive and comparative type. Research data were collected in the obstetrics clinic of a Maternity Hospital between August 15, 2019 and February 15, 2020. The study sample consisted of 160 pregnant women who met the research criteria (80 pregnant women who received fundal pressure, 80 pregnant women who did not receive fundal pressure). Results The duration of the second and third stages of labor was found to be shorter in the nonfundal pressure group (t = −3.422, p = 0.001; t = 2.195, p = 0.030). When the groups were compared, the formation of perineal trauma and second‐degree laceration, episiotomy requirement, elongation of the episiotomy incision and cervical laceration rate were found to be significantly higher in the fundal pressure group χ2 = 10.794 p = 0.001; χ2 = 8.403 p = 0.004; χ2 = 10.014, p = 0.002; χ2 = 16.579 p = 0.000; χ2 = 16.276 p = 0.000). The 1st and 5th min Apgar scores of the newborns were lower in the fundal pressure group (t = −6.377, p = 0.000; t = −3.581, p = 0.001). The 1st, 5th, 10th, and 15th min oxygen saturation of the newborns were determined to be significantly lower in the fundal pressure group (t = −4.753, p = 0.000; t = −2.427, p = 0.016; t = −2.604, p = 0.010; t = −2.492, p = 0.014). Conclusion According to the study results, it was determined that the uterine fundal pressure has a negative effect on birth outcomes and neonatal oxygen saturation. Adverse effects of fundal pressure application should be revealed in different aspects.