Is it safe to ripen eggs for harvest — for embryo freezing and later IVF (in vitro fertilization) — before treatment for breast cancer?
Some oncologists are concerned because hormones given to ripen multiple eggs for harvesting raise estrogen levels far above normal. As discussed in “Embryo freezing,” adding letrozole or tamoxifen to the hormones may help block estrogen from being able to nourish breast cancer cells. So far, studies do not show that pregnancy after breast cancer causes cancer recurrence. Also, IVF does not appear to cause breast cancer.
