Fig. 1From: Effect modification by developmental stage of embryos on the association between late follicular phase progesterone elevation and live birth in fresh transfersSmooth curve fitting of the effect of serum progesterone values on live birth in cleavage-stage and blastocyst-stage embryo transfers. Progesterone levels (ng/ml) are plotted on the x-axis, and live birth rates are on the y-axis. A crude model; B adjusted for covariatesBack to article page