1. The first visit at less than 10 weeks gestation :trans vaginal ultrasound with partially filled bladder to nullify effect of anteversion of the uterus for assessment of---the site of the intrauterine gestational sac in relation to the endometrial cavity . For the purposes of this study and to obtain consistent findings, it was decided to have only five subgroups of gestational site implantation in relation to the endometrial cavity (Fig. 2):