Table 1 Demographic characteristics of the pregnant women and their fetuses in this study
From: Prenatal phthalate exposure and neurodevelopmental differences in twins at 2 years of age
Characteristics | Mean ± SD or n (%) | ||
|---|---|---|---|
Overall (n = 97) | MCDA (n = 31) | DCDA (n = 66) | |
Mother | Â | Â | Â |
Maternal age (years) | 30.7 ± 3.9 | 30.0 ± 4.4 | 31.1 ± 3.6 |
Pre-pregnancy BMI (kg/m2) | 21.9 ± 3.1 | 21.3 ± 2.9 | 22.2 ± 3.2 |
Maternal education, n (%) | Â | Â | Â |
 High school or below degree | 77 (79.4) | 26 (83.9) | 51 (77.3) |
 College or above degree | 20 (20.6) | 5 (16.1) | 15 (22.7) |
Secondhand smoke exposure in pregnancy, n (%) | Â | Â | Â |
 NO | 70 (72.2) | 22 (71.0) | 48 (72.7) |
 YES | 27 (27.8) | 9 (29.0) | 18 (27.3) |
Self-reported cosmetic use, n (%) | Â | Â | Â |
 NO | 50 (51.9) | 10 (32.3) | 40 (60.6) |
 YES | 47 (48.5) | 21 (67.7) | 26 (39.4) |
Twins | Â | Â | Â |
Gestational age (weeks) | 36.7 ± 1.4 | 36.7 ± 1.6 | 36.7 ± 1.2 |
Birthweight discordance, n (%) | Â | Â | Â |
 ≤ 20% | 84 (86.6) | 27 (87.1) | 57 (86.4) |
 > 20% | 13 (13.4) | 4 (12.9) | 9 (13.6) |
Sex types of twin fetuses, n (%) | Â | Â | Â |
 Male-male | 37 (38.2) | 17 (54.8) | 20 (30.3) |
 Female-female | 33 (34.0) | 14 (45.2) | 19 (28.8) |
 Male-female | 27 (27.8) | 0 (0) | 27 (40.9) |
The use of ART, n (%) | Â | Â | Â |
 NO | 68 (70.1) | 30 (96.8) | 38 (57.6) |
 YES | 29 (29.9) | 1 (3.2) | 28 (42.4) |
Intra-twin MDI difference | 10.8 ± 7.8 | 9.6 ± 6.1 | 11.3 ± 8.5 |
Intra-twin PDI difference | 11.4 ± 11.2 | 10.0 ± 11.2 | 12.1 ± 11.2 |