Consent in this case requires informed consent.
Notably lacking in case of egg donation is research into the long-term health effects. We've had over 30 years of egg harvesting and there's a dearth of studies looking into long-term consequences for the donors. And that's worldwide.
When given advice before donating and then consenting, most women are not adequately informed about increased cancer risk, loss of fertility, risk of strokes, kidney disease, heart attacks or death. They are not informed about the risk of artificially inducing menopause decades before it happens naturally (that's what the first step in the process is that waitwhat23 has detailed above.) It often involves a drug like Lupron, the type of drugs used to block puberty. (Whose dangerous side effects for women and children we've discussed at length on other threads.)
There is also no research into the long-term health outcomes for women whose natural cycle is stopped and restarted in this way several times. Which happens a lot with egg donors.
And that's just step one.
Equating this dangerous procedure with sperm donation even in terms of consent betrays a clear lack of knowledge about how these women are "informed". There's a lot of statements from the typically young and poor women who are solicited for their eggs to support this criticism.
They are not fully informed, because if they were, few women would risk it in my view. And that's leaving aside the question of informed consent being possible at all when the long-term consequences are severely underresearched.