Additional file 4: of The risk of secondary sex ratio imbalance and increased monozygotic twinning after blastocyst transfer: data from the Japan Environment and Childrenâ s Study

Odds ratios of MZT by method of fertilization and parentsâ conditions. CT (early cleavage-stage embryo transfer), BT (blastocyst transfer), smoking and alcohol consumption habits at pregnancy recognition, SF-8 score of 50 or less. Low education: defined by the highest academic background and categorized as high school graduation or lower, Low income: defined by the annual revenue of the household and categorized as an annual income of 4,000,000 Japanese yen or less. (XLS 45 kb)