Nikki Bella has resorted to ''masturbating'' in bed next to her fiancé Artem Chigvintsev while he sleeps, because he won't have sex with her whilst she's pregnant.

The 36-year-old retired professional wrestler is currently 29-weeks pregnant with her and Artem's first child, and has revealed her beau is so nervous to have sex with her whilst she's pregnant, that she's had to take measures into her own hands.

She said: ''[Artem] will start to get into it, [but once he feels the bump] it's just like: boner crusher.

''Like, I'm so horny. I literally had to tell him today ...'When I wake up at 3 am and you're sound asleep, I literally masturbate next to you'.

''I make sure that he's like breathing really hard so he won't wake up because I'm too lazy to get out of bed. But I'm like, that's the only way I get some.''

Nikki's twin sister Brie is also expecting a baby with her husband Daniel Bryan, but hasn't been having the same problems in the bedroom, because the couple already have two-year-old daughter Birdie.

Brie confessed: ''I've been lucky enough to have some pregnancy sex.''

And Nikki said her sister ''gets it a lot more'' than she does, but noted her twin was in the same position during her first pregnancy.

Speaking during the latest episode of their podcast, 'The Bellas Podcast', Nikki said: ''But Bryan was this way the first time. Guys the first time around, when the bump starts to get big, they get weird.''

Meanwhile, Nikki previously admitted her and 'Dancing With the Stars' professional Artem's sex life is ''on and off'' now she's pregnant.

She said: ''I feel bad because Artem and I, we went from the honeymoon stage and then we got engaged and then I found out I was pregnant two weeks later. And everything changed so quickly. He has to deal with crazy hormones right now and trying to piece life together, and I deal with a lot of construction ... so, poor guy. Our sex life goes so on and off. And I don't know if it's me. I will admit, last night it was the first time that I told him, 'Hey, can you massage my boobs?' And then I pushed the hand lower and was like, 'Can you massage down there, too?' ''