Table 2. Sample Characteristics by Subgroups
Variable Category Natural Artificial p value
Combined Vaginal Oral Combined Vaginal Oral
Age 38.3 (4.35) 38.6 (3.27) 38.2 (3.27) 39.0 (3.04) 38.9 (3.62) 39.2 (3.75) 0.836
BMI 24.4 (3.40) 25.0 (4.11) 23.3 (3.39) 24.1 (3.85) 25.2 (5.95) 25.5 (4.17) 0.175
Birth weight 3255 (372) 3203 (474) 3000 (455) 3338 (556) 3278 (451) 3320 (266) 0.404
Embryo stage 4 - 4 (1.3) 8 (2.7) - - - 0.003
5 15 (5.0) 114 (38.1) 33 (11.0) 22 (7.4) 39 (13.0) 15 (5.0)
6 - 23 (7.7) 5 (1.7) 2 (0.7) 14 (4.7) 5 (1.7)
Endometriosis Yes 1 (0.3) 10 (3.4) 2 (0.7) 4 (1.4) 6 (2.0) 1 (0.3) 0.479

Note: Continuous data (age. BMI. and neonatal weight) are expressed as mean ± standard deviation (ANOVA).
Categorical data are expressed as frequencies and percentages (chi-square test).
The p-value in bold indicates a statistically significant difference between the groups