Pregnancy does not automatically exempt a woman from the obligation of Hac. If a pregnant woman has the financial means, a mahram, and is physically able to perform the rites, Hac remains farz upon her. Her Hac is valid if she performs it while pregnant — there is no scholarly disagreement on the validity of a pregnant woman's Hac. The key consideration is whether she can safely perform the rites without undue hardship.
Sheikh Ibn Baz stated that a pregnant woman should assess her ability to perform Hac based on her health condition and the stage of pregnancy. If she is in the early stages and has no complications, she may perform Hac. If she is in the later stages or has complications, she may delay until a future year when she is able. He emphasized that Hac is a lifetime obligation — there is no rush to perform it in a year where genuine hardship exists.
Sheikh Al-Fawzan added that a pregnant woman should consult a trusted physician before deciding to perform Hac. If the doctor advises that the journey and the physical demands of Hac (walking, standing at Arafat, the crowds) could harm her or the unborn child, then she has a valid excuse to delay. The principle in Islamic law is that preserving life takes precedence, and no one is obligated to perform an act of worship that would cause serious harm. If she cannot perform Hac due to pregnancy-related complications year after year, and her condition becomes permanent, she may appoint a proxy.