Parturition pit: the bony imprint of vaginal birth.
OBJECTIVE
To retrospectively evaluate for pits along the dorsum of the pubic body in females and compare the presence/absence of these pits to vaginal birth data.


METHODS
We retrospectively reviewed females with vaginal birth data who underwent pelvic CT. The presence of pits along the dorsum of the pubic body, pit grade (0 = not present; 1 = faintly imperceptible; 2 = present; 3 = prominent), and the presence of osteitis condensans ilii, preauricular sulcus, and sacroiliac joint vacuum phenomenon were assessed on imaging. Musculoskeletal radiologists who were blinded to the birth data evaluated the CTs. 48 males were also evaluated for the presence of pits.


RESULTS
482 female patients underwent CT pelvis and 171 were excluded due to lack of vaginal birth data. Of the 311 study patients, 262 had prior vaginal birth(s) and 194 had pits on CT. Only 7 of the 49 patients without prior vaginal birth had pits. There was a statistically significant association between vaginal birth and presence of pits (p < 0.0001). Patients with more prominent pits (grades 2/3) had a greater number of vaginal births. As vaginal deliveries increased, the odds of having parturition pits greatly increased, adjusting for age and race at CT (p < 0.0001). No males had pits.


CONCLUSIONS
Our study indicates that parturition pits are associated with prior vaginal birth and should be considered a characteristic of the female pelvis. The lytic appearance of prominent pits on imaging can simulate disease and create a diagnostic dilemma for interpreting radiologists.
Department of Diagnostic Radiology, Musculoskeletal Imaging, The University of Colorado, 12631 East 17th Avenue, Mail Stop 8200, Denver, CO, 80045, USA. tatum.mcarthur@ucdenver.edu.
Tatum A
TA
McArthur
Department of Obstetrics and Gynecology, Division of Urogynecology and Pelvic Reconstructive Surgery, The University of Alabama at Birmingham, 176 F Suite 10382 619 19th Street South, Birmingham, AL, 35249-7333, USA.
Isuzu
I
Meyer
Department of Preventive Medicine, The University of Alabama at Birmingham, Medical Towers, MT 403, Birmingham, AL, 35249-4410, USA.
Bradford
B
Jackson
Department of Diagnostic Radiology, Musculoskeletal Imaging, The University of Alabama at Birmingham, 619 19th Street South, JTN 304, Birmingham, AL, 35249-6830, USA.
Michael J
MJ
Pitt
Department of Diagnostic Radiology, Musculoskeletal Imaging, The University of Alabama at Birmingham, 619 19th Street South, JTN 304, Birmingham, AL, 35249-6830, USA.
Matthew C
MC
Larrison
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010000:Osteitis / Q000000981:diagnostic imaging; D036801:Parturition; D010388:Pelvis / Q000000981:diagnostic imaging; D011630:Pubic Bone / Q000000981:diagnostic imaging*; D012446:Sacroiliac Joint / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed
Lytic lesion; Parturition pit; Pregnancy; Pubic symphysis; Vaginal birth