Table 3.
Pooled proportions of the timing of the appearance of the Sylvian, parietal occipital, and calcarine fissures in the fetus according to different gestational ages.
| Cortical Structure | Studies (n) | Visualized at 18–19 Weeks % (95% CI) [I2] |
Visualized at 20–21 Weeks % (95% CI) [I2] |
Visualized at 22–23 Weeks % (95% CI) [I2] |
Visualized at >24 Weeks % (95% CI) [I2] |
|---|---|---|---|---|---|
| Sylvian fissure | 6 | 97.69 (92.01–99.97) [74.8] 213/222 fetuses |
98.17 (94.83–99.83) [53.1] 24/255 fetuses |
98.94 (97.0–99.90) [0] 186/187 fetuses |
100 (97.45–100) a [0] 164/164 fetuses |
| Parieto-occipital fissure | 6 | 81.56 (48.41–99.26) a [74.8] 131/176 fetuses |
96.59 (83.24–99.75) [92.8] 225/255 fetuses |
96.85 (88.81–99.98) a [71.8] 136/141 fetuses |
100 (96.85–100) [0] 118/118 fetuses |
| Calcarine fissure | 5 | 37.27 (0.5–89.59) b [74.8] 59/126 fetuses |
80.42 (50.20–98.23) [95.1] 155/204 fetuses |
89.18 (73.97–98.19) [73.1] 82/91 fetuses |
96.02 (84.67–100) c [65.6] 69/72 fetuses |
a Five studies are included in this meta-analysis. b Four studies are included in this meta-analysis. c Four studies are included in this meta-analysis.