Whitney Port suffered five miscarriages after the birth of her son.
The 40-year-old star had an "extremely easy" first pregnancy with Sonny, now seven, but she has opened up about the struggles she and husband Tim Rosenman have faced in trying to expand their family further.
In a preview of her appearance on the 'SHE MD' podcast obtained by People magazine, Whitney said: "My first pregnancy was extremely easy. I went off my birth control and within a couple months I was pregnant. I had no issues, no complications.
"I didn't feel great, but it was a completely healthy pregnancy. I was 32.
"About a year after I had Sonny, I got pregnant again and then miscarried at around eight weeks, and I had another miscarriage after that."
She noted a doctor then suggested se see a fertility specialist and added: "At this point, I was 34 or 35. I've had a total of five miscarriages. One at eight weeks, a few at nine weeks, and one ended up at 11 weeks. All with heartbeats."
No complications were found, so Whitney and Tim went through a round of IVF (in vitro fertilisation) treatment and had two boy and two girl embryos which her doctors recommended she use, with the males having stronger grades.
But the 'Hills' star suffered a "mental breakdown" when she fell ill and couldn't go through with the embryo transfer.
She said: "The week before I did a transfer, I got extremely sick, throwing up so much that I ended up having to have an endoscopy, and it was just a whole situation.
"I ended up not being able to do the transfer and basically had, like a mental breakdown."
Whitney and Tim then decided to use a surrogate but she also tragically miscarried twice.
The 'With Whit' host explained: "We ended up doing two transfers with her and we used the girls even though they weren't graded as high. I wanted the girls. So, we put in one girl and she had a clot, a subchorionic haemorrhage.
"She went on bedrest, but then she miscarried, and the doctor recommended that we try again with her. He thought that it was just something random.
"We tried again with her, and the same thing happened, and heartbeat and everything. And then she miscarried. We obviously decided at that point we needed to take a little bit of a breather from everything."
The couple stepped away from the process for a year to figure out what to do next, and are now looking for a new surrogate.
Whitney said: "We had talked to a lot of people and we thought that maybe doing a fresh round of embryos and a new surrogate was the best option. I had decided I really felt like carrying was off the table for me.
"We still do have those two embryos from that last round. That could be better because I was younger, who knows, but the other two didn't work, so maybe that batch was bad.
"So, I went this summer at 39 years old, and did another round with a different doctor, and ended up getting one healthy embryo. A male embryo. And now we are on the search for a new surrogate."
