Punters are charged £300 for two hours with a “baby dwarf”.
During the appearances they wear a baby onesie and bonnet and carry round a joke dummy.
They often call the expectant parents “Mum and Dad” as they pose for photos.
Hayley B, who runs Hayley B Entertainments, says stag parties are also getting in on the act by hiring dwarves to add to the fun.
Critics have labelled the practice “demeaning” but performer Eric Bourne sees nothing wrong with it.
The 43-year-old, from Crawley, West Sussex, said: “I have done it for around six months now and I really enjoy it.
“The PC brigade finds things wrong with everything. They used to claim cartoons made people violent but I never thought that was the case. I reckon people should mind their own business and if we are happy, leave us to get on with our lives.”
Eric also says the job allows him the same standard of living he had in his previous career with the Post Office.
This is despite him only working two days a week instead of five.
Demand is so high that Hayley’s agency has to regularly turn bookings away.
And business has stepped up a gear after Meghan had a lavish shower for the next royal baby last week.
Hayley said: “The phone’s ringing off the hook. People love it. I don’t ask why, I just take the bookings. “It’s definitely got more popular over the past few years.
“We used to get a couple of calls a month.
“But with baby showers becoming more popular people want to celebrate in unusual ways.
“My guess is that this is one of them.”