Table 2 Prenatal ultrasound characteristics of mild VM in the early-onset and late-onset groups
|  | Early-onset group (n = 94) | Late-onset group (n = 230) | P value |
|---|---|---|---|
Isolated or not | |||
 Isolated | 51 (54.3) | 158(68.7) | 0.01 |
 Non-isolated | 43 (45.7) | 72(31.3) | |
Laterality | |||
 Unilateral | 62 (66.0) | 176 (76.5) | 0.05 |
 Bilateral | 32 (34.0) | 54 (23.5) | |
Symmetry | |||
 Symmetric | 62 (66.0) | 109 (47.4) | < 0.01 |
 Asymmetric | 32 (34.0) | 121 (52.6) | |
Transience | |||
 Transient | 26 (29.5) | 97 (42.5) | 0.03 |
 Non-transient | 62 (70.5) | 131 (57.5) | |
Intrauterine changes | |||
 Intrauterine regression | 46 (56.8) | 130 (58.0) | 0.03 |
 Intrauterine progression | 12 (14.8) | 13 (5.8) | |
 Intrauterine stabilization | 23 (28.4) | 81 (36.2) | |