Objective To study the spacing and types of postpartum diastasis recti abdominis (DRA) by using high-frequency ultrasound, and to establish the criteria for diagnosis and typing classification.

Methods A total of 326 pregnant women with postpartum routine recheck (3 days, 6 weeks and 3 months after delivery) in Xishan People's Hospital of Wuxi City from January to December 2020 were selected by convenient sequential acquisition method, and the spacing and maximum spacing position of DRA were measured by high-frequency ultrasound.

Results According to the improved classification criteria, the suspected and slightly separated types were the major types in 326 pregnant women, and the proportions of patients with suspected and slightly separated types were 39.88% and 28.83%, respectively at the 42 day follow-up after delivery; the proportion of separation returning to normal (≤ 2 cm) was 92.64% in the re-examination at 3 months after delivery. There were 101 cases with separation>3 cm in 6 weeks after delivery, and according to improved classification criteria, they were divided into type Ⅰ (supraumbilical separation) in 72 cases (71.29%), type Ⅳ-a (supraumbilical was equal to subumbilical) in 1 case (1.00%), type Ⅳ-b (supraumbilical was greater than subumbilical type) in 20 cases (19.80%), type Ⅳ-c (subumbilical was greater than supraumbilical) in 1 case (1.00%), type Ⅲ (umbilical type) in 6 cases (5.94%), and type Ⅴ in 1 case (1.00%), and the maximum separation distance was between the supraumbilical region and the umbilical ring region.

Conclusion Improved typing classification criteria is more conform to clinical practice, and is helpful to establish the timing and plan of rehabilitation treatment.