Perineal Body and Genital Hiatus in the Third Trimester and Risk of Perineal Laceration.
OBJECTIVE
We aimed to determine whether pelvic organ prolapse quantification measurements of genital hiatus (gh) or perineal body (pb) obtained in the late third trimester are predictors of obstetric perineal laceration in nulliparous women.


METHODS
Nulliparous women with singleton gestation were prospectively recruited after 35-week gestation, and gh and pb measurements were obtained. After delivery, determination of the presence and degree of perineal laceration were recorded. Correlation of gh and pb measurements with risk of perineal laceration (defined as second, third, or fourth degree) was assessed using the Wilcoxon rank sum test.


RESULTS
We recruited 224 patients and 133 met inclusion criteria after delivery. The mean (SD) age was 27.2 (4.0) years and mean (SD) prepregnancy body mass index was 24.1 (4.6) kg/m. Seventy patients (52.6%) had either a second-degree (n = 64) or third-degree (n = 6) laceration. No fourth-degree lacerations were recorded. We found no significant difference in the median gh (3.5 vs 3.0 cm, P = 0.34) and pb (3.5 vs 3.5 cm, P = 0.54) measurements among women with and without perineal lacerations.


CONCLUSIONS
Our data suggest that antenatal measurement of gh and pb does not correlate with the risk of obstetric perineal laceration in nulliparous patients undergoing spontaneous vaginal delivery.
From the Divisions of *Gynecologic Surgery and †Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN.
Erik D
ED
Hokenstad
Sherif A
SA
El-Nashar
Amy
A
Weaver
John B
JB
Gebhart
John A
JA
Occhino
D000328:Adult; D005260:Female; D006801:Humans; D022125:Lacerations / Q000453:epidemiology*; D007744:Obstetric Labor Complications / Q000453:epidemiology*; D010502:Perineum / Q000033:anatomy & histology* / Q000293:injuries*; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D011446:Prospective Studies; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D018709:Statistics, Nonparametric; D055815:Young Adult