Table 7. In vitro fertilization (IVF) intra-cycle characteristics and assisted reproductive technology (ART) outcomes according to body mass index (BMI) classes (n=493).
Underweight Normal weight Overweight Obesity p-value
(<18.5 kg/m2) (18.5-24.9 kg/m2) (25-29.9 kg/m2) (>30 kg/m2)
(n=23) (n=285) (n=106) (n=79)
ICSI (%) 9 (39.1) 147 (51.6) 57 (53.8) 44 (55.7) NSg
Gonadotropin dose (IU) 1672.83±949.43 2254.60±932.83 2418.99±920.25 2576.44±1040.16 0.025a; 0.004b; <0.001c; 0.041e; NSd.f
Number of stimulation days 9.00±2.13 9.45±1.90 10.26±2.28 10.54±2.19 NSa.b.c.f; 0.003d; <0.001e
Number of follicles 13.00±10.74 12.94±9.67 16.04±10.73 15.15±11.10 NSa.b.c.d.e.f
Number of COC 8.00±5.99 10.46±7.83 12.56±7.77 9.63±7.08 0.047b; NSa.c.d.e.f
Oocyte immaturity rate (%) 18.96±22.18 16.86±16.85 18.98±18.03 19.07±20.13 NSa.b.c.d.e.f
Number of 2PN oocytes 4.91±4.06 4.89±3.96 5.70±4.15 4.84±4.04 NSa.b.c.d.e.f
Fertilization rate (%) 65.09±30.40 50.00±26.75 46.61±26.61 52.60±27.24 0.020b; NSa.c.d.e.f
Cleavage rate (%) 100.00 97.09±10.67 97.81±7.94 98.66 NSa.b.c.d.e.f
Blastocyst rate (%) 5.60 6.99 9.12 3.78 NSa.b.c.d.e.f
Number of obtained embryos 2.43±2.57 2.41±1.81 2.83±2.08 2.47±2.05 NSa.b.c.d.e.f
Number of IVF cycles with freeze all [n (%)] 8 (34.8) 113 (39.8) 53 (50.0) 34 (43.0) NSg
Number of criopreserved embryos 1.84±3.04 1.41±1.95 1.81±2.23 1.42±2.09 NSa.b.c.d.e.f
Positive βHCG [n (%)] 9 (39.1) 140 (49.1) 57 (53.8) 38 (48.1) NSg
Clinical pregnancy rate (%) 26.5 40.3 41.4 31.4 NSg
Cumulative clinical pregnancy (%) 29.4 44.0 52.2 35.7 NSg
LBR (%) 26.5 34.5 32.1 29.3 NSg
CLBR (%) 29.4 37.6 42.2 31.9 NSg
Endometrial thickness on the day of the last monitoring (mm) 9.65±1.72 9.63±1.93 10.07±2.16 10.60±2.23 NSa.b.c.d.f; 0.001e
Endometrial thickness on oocyte pick-up day (mm) 11.47±2.72 10.22±2.19 10.56±2.00 11.13±2.39 NSa.b.c.d.e.f

Data expressed as mean±standard deviation. p-value < 0.05 was considered statistically significant. ICSI - Intracytoplasmatic sperm injection; IU - International units; COC - cumulus-oocyte complexes; 2PN - two pronucleated; IVF - in vitro fertilization; βHCG - human chorionic gonadotropin hormone; LBR - live birth rate; CLBR - Cumulative live birth rate; NS - not statistically different; a - Comparison between underweight and normal weight (One Way ANOVA); b - Comparison between underweight and overweight (One Way ANOVA); c - Comparison between underweight and obesity (One Way ANOVA); d - Comparison between normal weight and overweight (One Way ANOVA); e - Comparison between normal weight and obesity (One Way ANOVA); f - Comparison between overweight and obesity (One Way ANOVA); g - Chi-square test.