Praise be to Allah.
Polycystic ovary syndrome (PCOS) is regarded as a common gynaecological disorder, the rate of which varies from one country to another, but on average it affects between 5 to 10 percent of women, but this rate is increasing. This illness may lead to delay in conceiving or repeated miscarriages, and it may cause other symptoms such as irregular periods, weight gain, high blood pressure, and the growth of coarse hair in various parts of the body.
Therefore if there is a marriage proposal and this illness is present, it is essential to inform the suitor of it, because any defect or illness that will lead to missing out on the aims of marriage, such as physical pleasure, compassion and love, or may be off-putting to the other spouse, must be disclosed, and it is prohibited to conceal it.
Ibn al-Qayyim (may Allah have mercy on him) said:
By analogy, any defect that would put the other spouse off and would lead to missing out on the aims of marriage, such as compassion and love, requires that the other party be informed and given the choice (of whether to proceed with the marriage or not).
End quote from Zaad al-Ma‘aad (5/166).
It says in Fataawa al-Lajnah ad-Daa’imah (19/15):
If the girl has a problem in the uterus, or with her menstrual cycle, that requires treatment and may delay conception, should the suitor be informed of that?
Answer: If this problem is something temporary, the like of which happens to women then passes, then it is not essential to inform the suitor of it. But if this problem comes under the heading of illnesses that will have some impact, or is not something minor and temporary, then if it is still ongoing at the time of a marriage proposal, and she has not recovered from it, then her guardian must inform the suitor of that. End quote.
Shaykh ‘Abd al-‘Azeez Aal ash-Shaykh, Shaykh Saalih ibn Fawzaan al-Fawzaan, Shaykh Bakr Abu Zayd
See also the answer to question no. 43496
And Allah knows best.