Systematic review and meta-analysis of the inter-recti distance on ultrasound measurement in nulliparas.

The objective is to evaluate the inter-recti distance on ultrasound measurement at different locations in healthy nulliparas. Electronic databases were searched for studies describing the inter-recti distance measured by ultrasound in healthy nulliparas. We excluded studies without descriptions of the measurement position or the condition of the abdominal wall. A meta-analysis was performed to evaluate the inter-recti distance on ultrasound measurement. Seven eligible studies with 295 healthy nulliparas were included. The location of the inter-recti distance measurement by ultrasound was not uniform. The pooled data divided the measurement locations into three areas. The meta-analytic summary values of the umbilical inter-recti distance of the nulliparas was 8.77 mm (6.56-10.99 mm), the distance at the epigastric area was 7.22 mm (2.76-11.68 mm), and that at the infraumbilical area was 4.09 mm (1.55-6.64 mm). The maximal reported inter-recti distance in healthy nulliparous women is smaller than 10 mm on ultrasound measurement at all locations and the range in the umbilical area is larger than that in the epigastric, infraumbilical areas. The values for the inter-recti distance reported in this systematic review can be used as the reference of feasible and desirable distance of the rectus muscles after rectus fascia plication. The limitation was that the methodological quality of the assessment in most studies was unclear or low.