A couple of months ago, I had considered asking my pregnant wife if she wanted to do a maternity photoshoot. But I decided that I would just shoot it myself.
I already have a DSLR camera. And if I wanted studio effects, I can just use a photo-editor to get them (eg, desaturate the colors, blur the backgrounds, filters, etc). You'll be amazed at how amazing your shots turn out.
If you don't already have a DSLR camera, you may considering investing in one. Along with an external flash unit, it'll set you back about HK$5,000 to 6,000. I'm sure your husbands/partners will be more than happy to photograph you! And you'll be able to continue using it to photograph your kids after birth.