Hi, thanks for asking in Health care Magic. Ovulation and pregnancy are due to the inter relationship between various hormones and complete balance between these hormones is necessary for a normal conception. In PCOS, this hormonal balance is altered, leading to difficulty in conception. Nolvadex D is Tamoxifen Citrate an alternative drug to Clomiphene Citrate used routinely to stimulate ovulation in PCOS. The rate of ovulation and pregnancy are claimed to be higher with Tamoxifen than with Clomiphene and that s why your Dr has prescribed it for you. It has a direct action on ovary and is very effective in stimulating ovulation. Hypothyroidism or thyroid deficiency inhibits ovulation and so your thyroid deficiency should be corrected first. In persons with thyroid deficiency, there may be an associated prolactin abnormality. Increased prolactin level is often seen in PCOS and if present, it needs to be corrected to improve your chances of conception. Tamoxifen will definetly increase your chances of pregnancy. It s dose can be increased up to 80 mg. Presently, it is given only in the dose of 20 mg for you. After correcting thyroid and prolactin (if present) problems, if still you don t have a mature ovum in follicle study, your treating Dr will increase the dose of Tamoxifen to improve your chances of pregnancy. I hopr this is useful to you.