Table 1.
Characteristics of three groups of monochorionic twin pregnancies
| Group 1 (n = 9) | Group 2 (n = 9) | Group 3 (n = 8) | p value | |
|---|---|---|---|---|
| Maternal age at delivery | 31.4 ± 6.2 | 31.1 ± 3.2 | 32.4 ± 2.2 | 0.80# |
| Gestational age of delivery (weeks) | 36.7 ± 0.97 | 34.8 ± 1.7 | 30.7 ± 2.7 | < 0.001#(Group1 > Group2 > Group 3) |
| Birth weight of the AGA (larger) twin (g) | 2597 ± 271 | 2237 ± 395 | 1398 ± 403 | < 0.001#(Groups 1 > Group 2 > Group 3) |
| Birth weight of the sIUGR (smaller) twin (g) | 2333 ± 276 | 1573 ± 300 | 717 ± 232 | < 0.001#(Groups 1 > Group 2 > Group 3) |
| Birth weight discordance (%) | 10.0 ± 6.6 | 29.5 ± 7.4 | 48.9 ± 7.4 | < 0.001#(Groups 3 > Group 2 > Group 1) |
| Cord plasma EPO-ratio | 1.03 ± 0.20 | 1.36 ± 0.76 | 1.95 ± 0.59 | 0.01#(Group3 > Groups 1 and 2) |
| Cord plasma EPO of larger (AGA) fetus (mIU/ mL) |
14.2 ± 11.4 | 10.5 ± 9.2 | 24.7 ± 36.8 | 0.410# |
| Cord plasma EPO of smaller (sIUGR) fetus (mIU/ mL) | 16.0 ± 14.6 | 12.7 ± 9.3 | 49.4 ± 71.8 | 0.153# |
| Maternal BMI at delivery | 26.6 ± 1.9 | 27.4 ± 3.4 | 27.1 ± 3.2 | 0.880# |
| CPR of larger (AGA) fetus | 1.39 ± 0.21 | 1.47 ± 0.29 | 1.74 ± 0.29 | 0.064# |
| CPR of smaller (sIUGR) fetus | 1.41 ± 0.20 | 1.33 ± 0.13 | 0.45 ± 0.03 | < 0.001#(Group3 < Groups 1 and 2) |
| Neonatal hemoglobin levels (larger/AGA) (g/dL) | 14.8 ± 1.2 | 16.4 ± 1.8 | 16.8 ± 1.1 | ※ |
| Neonatal hemoglobin levels (smaller/sIUGR) (g/dL) | 14.4 ± 1.2 | 16.5 ± 2.3 | 15.6 ± 1.7 | ※ |
Group 1: normal MC twins; group 2: twins with sIUGR without UA Doppler abnormalities; group 3: twins with sIUGR and UA Doppler abnormalities
Birth-weight discordance: [(body weight of the larger or AGA twin - body weight of the smaller or sIUGR twin) / body weight of the larger or AGA twin] × 100%
Cord plasma EPO-ratio: [plasma EPO level of the smaller (or the small-for-gestational-age) twin] / [plasma EPO concentration of the larger (or the appropriate-for-gestational-age) twin]
CPR (cerebroplacental ratio) = (middle cerebral artery-pulsatility index) / (umbilical artery- pulsatility index)
Abbreviations: MC monochorionic, sIUGR selective intrauterine growth restriction, AGA appropriate-for-gestational-age, EPO erythropoietin, CPR cerebroplacental ratio
#One-way analysis of variance
※No significant difference was observed in the hemoglobin levels between the two fetuses in any of the groups of MC twins