Prevalence, Risk Factors and Consequences Related to Cesarean Scar Defect (Defect in Cesarean Scar)

The rates of cesarean section (CS) are rising all over the world. Worldwide the number of CS is millions every year. CS is one of the most frequently performed operation for women. As a consequence many women have a scar in their uterus. Cesarean scar may be associated with complications in later pregnancies. In recent years there have also been a few reports indicating that cesarean scar could potentially be associated with menstrual disorders and infertility. The impact of cesarean scar defect on long term welfare or quality of life is not clear.

In some women with a history of CS it is possible to recognise a defect in the site of previous uterotomy years after the performed CS by sonographic examination. This defect in the scar, also called as a niche, is a consequence of incomplete healing of the scar in the lower part of uterus. To date there is uncertainty relating to the factors that lead to poor healing of cesarean scar. Also impact of cesarean scar defect on later well-being and later pregnancies are not properly known.

The purpose of this study is to investigate the prevalence and the risk factors of cesarean scar defect. Also the impact of cesarean scar defect on women´s menstrual health, fertility, further deliveries and quality of life will be investigated.

This study is a prospective observational cohort study. Women at the age of 18-45 years who will give birth by elective or emergency CS will be asked to participate. Women are recruited within two days of CS. Women with known uterus anomaly or von Willebrand disease will be excluded.

The prevalence of scar defect will be evaluated by transvaginal sonography and contrast-enhanced sonohysterography using saline infusion. Both 2-dimensional and 3-dimensional sonography will be used. Sonographic evaluation will take place 6 months after the CS.

The following definition for CS scar defect will be used: myometrial discontinuity with a depth of ≥2 mm at the site of cesarean scar that communicates with the uterine or cervical cavity as seen on transvaginal sonography with or without saline infusion.

The prevalence of menstrual disorders will be evaluated 12 months after the CS. The subjects will be asked to report the number of menstrual bleeding days once a month during 3 consecutive months. Postmenstrual spotting is defined as ≥2 days of brownish discharge at the end of menstruation with total bleeding days of ≥7 or non-cyclic bleeding not related to menstruation.