Having a support person from early labor until after childbirth (such as a doula, nurse, midwife, or childbirth educator) has a proven, positive effect on childbirth. Women who have continuous one-on-one support are more likely to give birth without pain medication and are less likely to describe their birth experience negatively.1
Although there is not a proven direct connection between continuous support and less labor pain, having a support person does help you feel more control and less fear, which are strong elements of mental pain control.
Citations
WebMD Medical Reference from Healthwise