First and Second Stage Risk Factors Associated with Perineal Lacerations

• Published in: Maternal and child health journal Vol. 28; no. 7; pp. 1228 - 1233
• Main Authors: Saucedo, Alexander M., Tuuli, Methodius G., Gregory, W. Thomas, Richter, Holly E., Lowder, Jerry L., Woolfolk, Candice, Caughey, Aaron B., Srinivas, Sindhu K., Tita, Alan T. N., Macones, George A., Cahill, Alison G.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.07.2024; Springer Nature B.V
• Subjects: Childbirth & labor; Gynecology; Health risks; Maternal & child health; Maternal and Child Health; Medicine; Medicine & Public Health; Pediatrics; Pelvis; Population Economics; Public Health; Risk factors; Risk reduction; Secondary analysis; Sociology; Vagina; Perineal lacerations; Delayed pushing; Operative delivery; Amnioinfusion; Immediate pushing
• DOI: 10.1007/s10995-024-03919-1
• ISSN: 1092-7875; 1573-6628

Objective To determine intrapartum factors associated with perineal laceration at delivery. Methods This was a planned secondary analysis of a multicenter randomized clinical trial of delayed versus immediate pushing among term nulliparous women in labor with neuraxial analgesia conducted in the United States. Intrapartum characteristics were extracted from the medical charts. The primary outcome was perineal laceration, defined as second degree or above, characterized at delivery in women participating in longer term pelvic floor assessments post-delivery. Multivariable logistic regression was used to refine risk estimates while adjusting for randomization group, birth weight, and maternal age. Results Among the 941 women participating in the pelvic floor follow-up, 40.6% experienced a perineal laceration. No first stage labor characteristics were associated with perineal laceration, including type of labor or length of first stage. Receiving an amnioinfusion appeared protective of perineal laceration (adjusted odds ratio, 0.48; 95% confidence interval 0.26–0.91; P = 0.01). Second stage labor characteristics associated with injury were length of stage (2.01 h vs. 1.50 h; adjusted odds ratio, 1.36; 95% confidence interval 1.18–1.57; P < 0.01) and a prolonged second stage (adjusted odds ratio, 1.64; 95% confidence interval 1.06–2.56; P < 0.01). Operative vaginal delivery was strongly associated with perineal laceration (adjusted odds ratio, 3.57; 95% confidence interval 1.85–6.90; P < 0.01). Conclusion Operative vaginal delivery is a modifiable risk factor associated with an increased risk of perineal laceration. Amnioinfusion appeared protective against injury, which could reflect a spurious finding, but may also represent true risk reduction similar to the mechanism of warm perineal compress. Significance The objective of this study was to examine intrapartum factors associated with an increased risk of perineal laceration at delivery among nulliparous women. Operative vaginal delivery and the length of second stage, particularly prolonged second stage, are modifiable risk factors associated with an increased risk of perineal laceration. Receiving an amnioinfusion appeared to be protective against perineal laceration. There are few intrapartum modifiable risk factors other than operative delivery for perineal laceration in nulliparous women. Length of the second stage is an important risk factor for perineal lacerations that is modifiable through active management.