Ultrasonographic assessment of LUS excellent, non-invasive and cost effective method for safely predicting scar integrity: Study
A caesarean section is a frequently performed surgical procedure in obstetrics and is also among the oldest known operations. The classical caesarean section (CS) involves a longitudinal incision in the upper uterine segment, providing a larger space for delivering the baby. However, this method is now rarely used due to its higher risk of complications. Today, the lower uterine segment caesarean section (LSCS) is the most commonly employed technique. This procedure involves making a transverse incision just above the bladder, which results in less blood loss and is easier to repair. Depending on specific conditions such as the presence of lateral varicosities, a constriction ring, or a deeply engaged head, the incision can be transverse, which is typical, or vertical.
With the increasing global rates of primary cesarean sections, there has been a corresponding rise in the occurrence of repeat cesarean sections. An antenatal ultrasonographic assessment of the lower uterine segment could contribute to the safety of women who are considering a trial of labor by identifying those with a lower risk of uterine rupture. This research aimed to investigate the relationship between ultrasonographic scar thickness and the intraoperative condition of the uterine scar, as well as the outcomes for both the mother and the fetus in cases where the patient has previously undergone a lower segment cesarean section (LSCS).
Patients of previous caesarian section cases as per inclusion criteria attending to Navodaya Medical College Hospital and Research Centre, Raichur during the study period of 2021-2023 were included in the present study. Patients found to have scar thickness ≥2.5 mm and fulfilling the above mentioned criteria were allowed a trial of labor. Patients with a scar thickness < 2.5mm were taken up for caesarean section and the lower segment was assessed intra-operatively. Obstetric outcomes were studied.
In the present study, it was observed that the majority of patients, 49 (49.0%), belonged to the age group of 25-29 years, followed by 33 (33.0%) in the 20-24 age group, and 14 (14.0%) in the 30-34 age group. Furthermore, the majority of patients, 76 (76.0%), were second gravida. Most patients, 85 (85.0%), were of primi gravida, and again, there was no statistically significant difference in parity found between groups (P>0.05). The high-risk group experienced a shorter gestational period in comparison to the low-risk group. Notably, 32% of patients in the low-risk group had an interdelivery interval of 2.5 to 3.5 years, while 60% of patients in the high-risk group had an inter-delivery interval of 1.5 to 2.5 years. NICU admission, required by 3% of newborns, reflects a broader spectrum of health issues that necessitate specialized care beyond standard postnatal care.
Ultrasonographic measurement of lower uterine segment (LUS) thickness between 36-40 weeks correlates well with intraoperative findings. A thickness of 2.5 mm or less is associated with a higher risk of an abnormal scar. Women with a previous cesarean section and a LUS thickness greater than 2.5 mm may be eligible for a trial of labor after cesarean (TOLAC), assuming no other contraindications. As scar thickness for TOLAC increases, the success rate of VBAC increases. It is important to spread knowledge regarding regular antenatal check-up, inter delivery interval and training of health care professionals at periphery level for timely referral of these cases to tertiary health care center for appropriate and timely management. Hence, Ultrasonographic assessment of LUS is an excellent, non-invasive and cost effective method for safely predicting scar integrity and can be recommended to be routinely incorporated in antenatal workup of a woman with previous caesarean section for making decision on the mode of delivery.
Source: Ruge et al. / Indian Journal of Obstetrics and Gynecology Research 2025;12(2):287–294
