AceShowbiz - Gabrielle Union has opened up about her fertility struggles, revealing she suffers from a form of endometriosis.

The Bad Boys 2 star, who is married to basketball legend Dwyane Wade, previously confessed to suffering multiple miscarriages in her book, We're Going to Need More Wine, and now she reveals that adenomyosis was the cause of her conception nightmare.

"Towards the end of my fertility journey I finally got some answers," she told fans at last week's BlogHer conference in New York. "Everyone said, 'You're a career woman, you've prioritised your career, you waited too long and now you're just too old to have a kid - and that's on you for wanting a career'. The reality is I actually have adenomyosis".

The condition causes the uterus to become enlarged, plaguing sufferers with heavy periods and chronic pain.

"The gag is I had it in my early 20s," Gabrielle added. "Instead of diagnosing me, they were like, 'Oh you have periods that last nine or 10 days and you're bleeding through overnight pads... perhaps there's something more there'. Every doctor I saw was like, 'Let me put you on birth control'. 'The pill can mask all kinds of things. It is amazing at preventing pregnancy; not so great with addressing adenomyosis".

And Union admits she has had to smile through the physical and emotional pain, especially when insensitive people quiz her about babies.

"People feel very entitled to know," she explained. "(They say), 'Do you want kids?' A lot of people, especially people that have fertility issues, just say 'no' because that's a lot easier than being honest about whatever is actually going on. People mean so well, but they have no idea the harm or frustration it can cause".