Blac Chyna's mother warned Rob Kardashian he would lose his fiancee if he didn't stop acting like a ''baby''.

The 28-year-old make-up artist - who is expecting a baby girl with the sock designer - took her partner to visit her family in Washington DC and her mom Tokyo Toni tearfully confronted her partner about his unpredictable behaviour.

After Chyna told her mother that Rob ''needs to work on a few things'' for the sake of their relationship and family, Toni said:

''You're dealing with my only child, she didn't have a father around. She don't need a baby with no father, do you understand me?

''You can't do what you're doing, you're gonna ruin it.''

Rob had been reluctant to make the trip but agreed to do so as Chyna warned it could be ''make or break'' for their relationship, which began at the beginning of this year.

Speaking on 'Rob & Chyna', she said: ''This D.C. trip means so much to me and if Rob doesn't go this could be a make or break in our relationship.''

And Rob admitted: ''We are going to D.C. and being around people I don't know and out of my comfort zone.

''But my relationship with Chyna means everything to me so I am willing to do this.''

Later in the episode, Chyna took Rob on a tour of her old schools and other areas of her neighbourhood, but her 29-year-old fiance was left unhappy when she had their driver stop the car so she could take pictures with fans.

Rob was concerned about his weight and appearance in the pictures and got so upset he got back in the car.

A family dinner on the show was fractured by arguments between Chyna's parents, who are not together and hadn't seen each other in 10 years, as Tokyo Toni was stunned that her daughter's half-siblings were born to different women within a few months on one another.

Chyna said: ''My dad was a player. I hope my mom can keep it together and we can have a good dinner.''

But despite the rows, Chyna - who also has three-year-old son King Cairo with ex-partner Tyga - was pleased Rob had made the effort on the trip.

She said: ''I'm really happy and surprised that Rob decided to come out with my family.

''I hope he keeps this up back in LA.''