Kim Kardashian West hasn't explained to her children that their sibling will be born via a surrogate mother.

The 37-year-old reality star and her husband Kanye West are gearing up to welcome their third child into the world in the coming months, but the star admits she is yet to tell her daughter North, four, and son Saint, 23 months, about the process of someone else giving birth to their sibling.

Explaining why she chose not to invite the surrogate to her baby shower which was held over the weekend, Kim said: ''I, um, I did not [invite the surrogate]. I did introduce her to my family. I introduced her to my family earlier that day. And, you know, I just thought, I don't know, it was like a weird decision to have to make. Of course, I would've wanted her to be there and be a part of it, but I hadn't really gone that far in explaining it to my kids yet. So I have to figure that out first before they really see and then if we're celebrating, you know, her, I just want to celebrate the baby. I think I have to explain it to my kids first and figure out how I'm going to explain it to them.''

The 'Keeping Up with the Kardashians' star and her rapper spouse, 40, chose to hire a surrogate to carry their baby after Kim was advised by doctors not to get pregnant a third time, as she suffered complications whilst carrying both North and Saint.

And Kim believes she chose the ''perfect'' woman to be her surrogate mother, as she has the ''best relationship'' with her.

Speaking during an appearance on 'The Real' on Thursday (16.11.17), she said: ''I love her. I have the best relationship with my surrogate. She's so nice. She is the perfect person to do this for my family. She's great. She's been amazing.''

Despite being pleased with her choice of surrogate, Kim revealed she is finding the process ''so much harder'' than being pregnant herself, as she is struggling with the lack of control she has over her unborn tot.

She said recently: ''You know, it is really different. Anyone that says or thinks it is just the easy way out is just completely wrong. I think it is so much harder to go through it this way, because you are not really in control.

''And, you know, obviously you pick someone that you completely trust and that you have a good bond and relationship with, but it is still ... knowing that I was able to carry my first two babies and not, you know, my baby now, it's hard for me. So, it's definitely a harder experience than I anticipated just in the control area.''