PLOD1 and spontaneous abortion: Univariate analyses showed that age, BMI, baseline LH levels, peak E2 levels on the day of hCG injection, the number of retrieved oocytes, and the number of embryos transferred were correlated with the pregnancy rate, LBR, singleton pregnancy rate and multiple pregnancy rate (all P < 0.05) and that age and BMI were correlated with the miscarriage rate and preterm delivery rate (all P < 0.05).