TUCS - Version 1
Research type
Research Study
Full title
TUCS: Transvaginal ultrasound assessment of uterine scar following caesarean section
IRAS ID
261256
Contact name
Raffaele Napolitano
Contact email
Sponsor organisation
University College London
Duration of Study in the UK
3 years, 0 months, 0 days
Research summary
Summary of Research
Caesarean section rates are steadily increasing in the UK with a corresponding increase in associated complications. The caesarean section scar “defect’ has been reported as an important feature that is associated with caesarean section complications. It has been demonstrated that it may be the causative factor for abnormal or painful menstrual bleeding, obstetric complications in subsequent pregnancies and possibly subfertility.
Recent studies have shown that women with a previous caesarean section at late first stage or at full dilatation are at increased risk of preterm birth (babies born before 37 weeks) in future pregnancies. Preterm birth and its associated complications are the leading cause of death for children under the age of five worldwide. A large US study showed 13.5% of women who had previous full dilatation caesarean section (FDCS) had a subsequent preterm delivery. The risk appears to increase progressively with the degree of dilation during emergency caesarean section.
We believe that late first stage caesarean section or FDCS can lead to structural damage of the cervix and compromise its function, leading to lack of mechanical support in a future pregnancy and subsequent SPTB. A mechanism for the observed association is yet to be determined.
We are looking to invite women who have had a previous emergency caesarean section for a transvaginal ultrasound scan (TVUS) post delivery. We would like to assess the caesarean scar characteristics and its location in relation to the cervix. These characteristics will then be correlated with the participant demographics, medical and obstetric history from the previous pregnancy and subsequent future pregnancy outcomes. This will help us in establishing a mechanism for the observed association with preterm birth. The findings are expected to be beneficial in counselling, further investigation and management of women in future pregnancies.
Summary of Results
Cesarean delivery scars were identified in 96.8% of women recruited (90/93). Advanced labor cesarean delivery (8-10 cm dilatation) was associated with an eight-fold increased likelihood of a scar located at or caudal to the internal os (RR 7.77; 95% CI 2.59, 23.39; p<0.001) compared to cesarean birth performed earlier in labor (4-7 cm dilatation). Cervical dilatation and fetal station at surgery significantly influenced scar position relative to the internal cervical os (p<0.001). For each 1cm increase in cervical dilatation during labor, the scar was positioned 0.88mm more caudally on the uterus or cervix (95%CI 0.62, 1.14; p<0.001). Similarly, for each 1cm descent of the fetal part within the maternal pelvis, the cesarean scar was located 1.5mm more caudally on the uterus or cervix (95%CI 0.71, 2.33; p<0.001). The niche prevalence was 37.8% (34/90), of which 67.6% (23/24) had a healing ratio ≤0.5. Risk factors for suboptimal scar healing included BMI ≥ 25, increased uterine artery vascular Doppler resistance, gestational age > 40 weeks, the use of locking sutures during surgery and cesarean delivery scar location caudal to the internal os on postnatal ultrasound (p<0.05). Uterine scars, situated cranial to the internal os, had significantly larger niche dimensions compared to those located within the cervix, at or caudal to the internal os (p<0.05).
REC name
London - Central Research Ethics Committee
REC reference
20/LO/0438
Date of REC Opinion
6 Jul 2020
REC opinion
Further Information Favourable Opinion