Hi, It is true that estrogen supplements are to be avoided in pregnancy. Their use prior to pregnancy is based on the specification of the consultant as to the need for use. If there is the utmost necessity for endometrial proliferation prior to ovulation, they need to be used. Otherwise, the embryo may fail to implant. So, your doctor is the better judge. Vaginal suppositories or patches may be sued instead of oral medication for reduced systemic effects. Hope you find this information useful. Take care.