"clot" in the uterus

Hello everyone. please help. thanks a million in advance
my friend missed her period for a couple of months and she felt a great pain in her womb. she visited two gynecologists who urged her to undergo a caesarian section to remove "maybe a clot of blood" that accumulated in her uterus. she ultimately underwent the surgery and now she feels well. it has been now a year. she is getting married soon but she is worried and has some questions:
1) what are the causes of this?
2) can she get pregnant or does she have to wait for a couple of years more ?  noting that women who deliver with a caesarian operation must keep a period of at least 4 years between deliveries (i have been told)
3) will she be able to give birth naturally  or has she got to undergo a caesarean section every time she wants to deliver?
4) she is 27 now, what can she do to avoid such menstrual problems?

[Mrs_Baze]

I can't answer all your questions, but I might be able to help a little. My mother in law had all three of her boys just about a year apart from each other,all via cesarean. Your friend does not need to wait 4 years between pregnancies unless her doctor tells her too for some reason. Also, vaginal birth after cesarean (vbac) are a real thing; she will have to discuss with her doctor whether or not it's a good idea to try it in her situation. Hope this helps!