DISCUSSION
Main findings
This systematic review aimed to evaluate the research evidence of how different lubricants could contribute in reducing the severity of perineal trauma. Nineteen trails enrolling 5445 women were eligible for inclusion. Our meta-analyses showed that with moderate certainty of evidence, lubricant use reduced the incidence of second-degree perineal laceration; and with very low to low certainty of evidence, lubricant reduced the incidence of perineal trauma, episiotomy, and shortened the duration of second-stage labor, but did not affect rates of intact perineum, first-degree perineal laceration, severe perineal laceration, postpartum hemorrhage and Apgar score. Subgroup analysis indicated that women with obstetric gel had a shorter duration of the second-stage when compared with liquid wax. For nulliparous women, lubricant use reduced the incidence of perineal trauma, second-degree perineal laceration, shortened the duration of second-stage labor, and increased the rate of intact perineum. For multiparous women, lubricant use reduced the incidence of perineal trauma, first- and second-degree perineal laceration.