Question: Is hormonal therapy a treatment option if I am pregnant or want to get pregnant?
Answer: The use of tamoxifen has been evaluated in thousands of women, and we have also studied it in a variety of different settings. One area where it has not been evaluated is in pregnant women, and the reason that we have caution -- and actually, an approach that says we should not use it in that setting -- is because we don't know what effect it will have on the fetus.
Tamoxifen, when it was initially being developed, was developed as a fertility drug in a sense; initially in animals, it was a drug that was similar to some of the fertility drugs that are currently available in some countries. The real reason tamoxifen was being developed as a drug was as a morning-after pill, and as it turned out, it actually promoted ovulation, which is just the opposite of what you would want in a morning-after pill.
So in women who are pregnant, we don't have a lot of information on the effect of the drug on the fetus, the developing child, so we would clearly not want to use the drug in that setting. If the woman was trying to get pregnant, we would not want to use tamoxifen in that setting either because, again, the same issue -- perhaps you are not entirely sure when the woman got pregnant, so continuing tamoxifen in that setting may have an adverse effect on the fetus. So a woman who is pregnant or a woman who is trying to get pregnant, we would avoid tamoxifen.
Previous: Is hormonal therapy a treatment option regardless of whether my hormone receptor status is positive or negative?