To analyze the effects of acupressure on the sanyinjiao point for pregnant women in labor at public maternity wards. Method: single-blind controlled clinical trial, randomly done employing a pragmatic profile. We selected 156 pregnant women in their >= 37 week/s, who had cervical dilations of >= 4 cm and with two or more contractions in 10 minutes. The pregnant women were randomly divided into three groups at a university hospital in the suburbs of Sao Paulo, Brazil, in order to receive either acupressure treatment, a placebo or participate as part of a control group. The acupressure was applied on the sanyinjiao point during the contractions for 20 minutes. Then the intensity of the pain was evaluated using the Visual Analogue Scale (VAS). Results: The averages for the pain measured using the VAS were not different for the three groups that were a part of the study (p-value=0.0929), however they were less in the acupressure groups immediately after receiving the treatment (p-value=< 0.0001). This was also the case where the treatment lasted for 1 hour (p-value=0.0001). This was the case in comparison with placebo and control groups. Conclusion: the use of acupressure on the sanyinjiao point is a useful way to alleviate pain in a non-invasive manner. It can improve the quality of care given to pregnant women in labor. Register: RBR-9mhs8r.24