When you are getting a follicular scan done for infertility there are two things that are important. One is the size of the follicle, other is the endometrial thickness, how ready is the uterus to accept the pregnancy. So the lining of the uterus also has to be thicker and ready for the acceptance of the pregnancy. In case it is not matching the follicular size, i.e. the follicle is ready to rupture but the uterus is not ready to accept the pregnancy there are medications which will make it thic