Table 2. Clinical data, hormonal profiles, and reproductive outcomes of euthyroid-infertile women according to blastocyst embryo transfer on day five (D5) or day six (D6).
Characteristics* Day of Blastulation p-value
D5 D6
n 212 (49.5%) 216 (50.5%) -
Female age (years) 34 [32 - 36] 36 [33 - 40] <0.001ª
BMI (kg/cm2) 22.83 [21.36 - 25.00] 23.13 [21.33 - 25.22] 0.738ª
Time trying to conceive (months) 24 [14.25 - 48] 24 [12 - 36] 0.357ª
Baseline FSH (UI/mL) 6.56 [5.32 - 7.80] 6.58 [5.24 - 7.69] 0.851ª
LH (mUI/mL) 5.59 [4.07 - 7.36] 5.34 [3.87 - 6.97] 0.279ª
Estradiol (pg/dL) 47.70 [32.80 - 70.87] 49.00 [33.92 - 73.36] 0.446ª
Prolactin (ng/mL) 13.22 [9.10 - 17.68] 13.00 [9.23 - 17.88] 0.957ª
TSH (mUI/mL) 1.66 [1.10 - 2.30] 1.9 [1.32 - 2.45] 0.023ª
FT4 (ng/dL) 1.15 [1.02 - 1.26] 1.13 [0.99 - 1.26] 0.299ª
Thyroid Peroxidase Antibody positive (n, %) 30 (14.2%) 28 (13.0%) 0.778b
Oocytes retrieved (n) 8 [5 - 14] 9 [5 - 13] 0.783ª
MII oocytes (n) 6 [4 - 11] 7.5 [4 - 11] 0.801ª
Embryos (n) 4 [2 - 6] 4 [2 - 6] 0.976ª
Embryos transferred (n) 2 [1 - 2] 2 [1 - 2] <0.001ª
Clinical Pregnancy rate (n, %) 109 (51.4%) 88 (40.7%) 0.033b
Miscarriage (n, %) 13 (11.9%) 10 (11.4%) 1.000b
Live births (n, %) 96 (88.1%) 78 (88.6%) 1.000b
Twins (n, %) 26 (27.1%) 18 (23.1%) 0.601b
Preterm (n, %) 17 (17.7%) 14 (17.9%) 1.000b

*Qualitative variables are presented as absolute and relative frequencies and quantitative variables as median and interquartile interval (IQR). BMI, Body Mass Index; FSH: Follicle-stimulating hormone; LH: Luteinizing hormone; TSH, thyroid-stimulating hormone; FT4, free Thyroxine MII: Metaphase II oocytes. ª: Mann-Whitney U test.