Cesarean section accounts for nearly 30% of births in Canada, and is the most commonly performed surgery by Obstetrician Gynecologists. Cesarean scar isthmocele, meaning a defect in the uterine wall at the site of a previous uterine incision, is a common complication of this surgery. While most are likely asymptomatic, isthmoceles can lead to major complications in pregnancy (uterine rupture, invasive placentation, cesarean scar ectopic pregnancy) and outside of pregnancy (abnormal uterine bleeding, infertility and pain). Studies have shown that the method used to suture the uterus at the time of a cesarean section may have an impact on the incidence of post-operative isthmocele formation. Our study is a randomized control trial of the impact of locked vs unlocked uterine closure at cesarean section on the incidence of isthmocele formation. Women undergoing cesarean section will be randomized to have either a locked or unlocked uterine closure. They will then return 6 months after their surgery for a transvaginal ultrasound to evaluate the presence or absence of an isthmocele.

This study is a pilot trial. The investigators hope to determine the feasibility of completing a large randomized control trial by recording: a) the number of patient who agree to participate in this study, b) the number of patients who receive the correct intervention and, c) the number of patients who return for their post operative ultrasound.

The investigators also plan to assess multiple secondary outcomes. First, the goal is to determine the isthmocele incidence within the study subjects of the pilot trial in order to perform a power calculation for a subsequent larger trial in this area. Another goal is to determine if the uterine closure techniques in this study lead to differences in surgical time, blood loss or the need for intra- or post-operative blood transfusion. Last, the study will collect data on the suture material most commonly used in this study to determine if this requires standardization in the subsequent larger trial.

Cesarean section accounts for nearly 30% of all deliveries in Canada, and is the most commonly performed surgery by Obstetrician Gynecologists (OBGYNs) in Canada. Therefore, it is important to understand the short and long-term complications of this procedure. Recently, emphasis has been placed on cesarean scar isthmocele as a long-term complication. An isthmocele is a defect at the cesarean section scar site with a depth of at least 1-2mm. Isthmoceles can lead to major obstetrical complications such as cesarean scar pregnancy, invasive placentation, and uterine rupture. More commonly, patients present with gynecologic symptoms: abnormal uterine bleeding, pain, and infertility. Up to 30-50% of patients with an isthmocele report symptoms when inquired. Isthmoceles have an incidence of 19-88% following cesarean section. This wide range is due to discrepancies in study technique, diagnostic criteria, and patient characteristics.

While medical and surgical treatment options are available for cesarean scar isthmocele, our focus should turn to prevention at the time of cesarean section. Evidence suggests double-layer (vs. single-layer) uterine closure decreases the formation of cesarean scar isthmocele and increases residual myometrial thickness (RMT). Additionally, uterine closure with a locked suturing technique may result in greater isthmocele depth and size, and a thinner RMT at the cesarean scar site. To our knowledge however, no study has determined the impact of a locked vs. unlocked double-layer closure technique on isthmocele prevention. Locked sutures, believed to be more hemostatic, may cause tissue necrosis and impair wound healing. Interestingly, evidence does not support reductions in operative blood loss with locked closure techniques. The hypothesis is that unlocked double-layer uterine closure can reduce isthmocele formation and thus improve longterm maternal outcomes without impacting operative blood loss or other short-term surgical outcomes.

Inclusion Criteria:

• Women undergoing their first cesarean section

Exclusion Criteria:

• previous uterine hysterotomy (caesarean section, myomectomy, etc.)
• known uterine anomalies
• active labour
• known bleeding disorder
• maternal connective tissue disorders

Since this is a study done at the time of cesarean section, only females are eligible.