Effective anatomical and functional status of the lower uterine segment at term Estimating the risk of uterine dehiscence by ultrasound
Sonographic lower uterine segment evaluation may be a good noninvasive, repeatable, safe technique for defining profile risk of uterine dehiscence or worse in women with previous cesarean section, especially more than 18 months later.
Salvatore Gizzo, M.D., Alessandra Zambon, M.D., Carlo Saccardi, M.D., Ph.D., Tito Silvio Patrelli, M.D., Stefania Di Gangi, M.D., Monica Carrozzini, M.D., Anna Bertocco, M.D., Giampiero Capobianco, M.D., Ph.D., Donato D’Antona, M.D., Giovanni Battista Nardelli, M.D.
Volume 99, Issue 2, Pages 496-501.e2, February 2013
To define the role of lower uterine segment (LUS) evaluation at term.
Observational case-control study.
Ninety-four patients were divided into two groups. Group-A consisted of 45 multiparous single foetus pregnant women with up to two previous caesarean sections. Group-B consisted of 49 multiparous pregnant women with up to three vaginal deliveries and no uterine scars.
Total lower-uterine-segment and myometrial thickness were measured by sonogram in all patients before undergoing a caesarean section.
Main Outcome Measure:
The primary outcome is to find a correlation between ecographic measurements and features of the lower-uterine-segment at the time of caesarean section. The secondary outcome is to define a correlation between the number of previous caesarean sections, inter-delivery interval time and features of the lower-uterine-segment (grade I to IV).
Sonographic measurements revealed significant differences in lower-uterine-segment size and myometrial thickness between the two Groups. Grades III-IV of lower-uterine-segment were only observed in Group-A. An inter-delivery-interval <18 months, lower-uterine-segment thickness ≤3.0 mm and myometrial thickness <1.5 mm were statistically significant predictors of loweruterine-segment grade III-IV. Number of previous CS showed no correlation with surgical loweruterine-segment status. Conclusions:
Sonographic evaluation of the lower-uterine-segment may be a non-invasive, reproducible and safe technique for defining the risk of uterine dehiscence, with a sensitivity of 100% and specificity of 85% (PPV 45%, NPV 100%).