Hellobee Boards

Loft! I've had good luck with them.
Gap might also have a black skinny ankle pant.

I used to get mine at JCrew but they discontinued their maternity line I know madewell is starting a maternity line but not sure if they'll have work pants. Might have a really nice black Jean though that you could possibly get away with.

Following. I also need a few things that look professional (for a male dominated industry) and so much maternity is casual or covered in floral prints. We have a local Pea in the Pod store which I'll probably go to soon. I think I may just skip looking for pants (ugh) and hope I don't freeze in dresses. I'm hoping dresses in neutral colors with cardigans will work well in a small professional capsule.

My favorite professional dresses were the "bodycon" I bought from https://www.isabellaoliver.com/us. I could get away with just needing a couple professional outfits since I don't see the same people every day or months on end. A pair of Ponte slacks from A Pea in the Pod served me well. I paired it with Motherhood plain tops and a maternity cardigan for more a business casual look.

All maternity black pants are awful. I got away with wearing leggings with a long cardigan or tunic and boots most days, but there are only 3 females including myself in my entire office, so I don't think anyone really cared or noticed. Seraphine has some nice items. I didn't try their pants but got a wrap dress which was nice and worked well for the office when I needed to see clients. I also bought a few things off of gilt and they were good quality and fit well, but the delivery time is usually long for maternity items.

@Meowkers: Depending on the "look" at your office (we aren't allowed to wear minnie pants), these are the pants I wear constantly:

http://www.gap.com/browse/product.do?vid=1&pid=549382002

Zulily has a bunch of cute stuff right now if you're willing to buy online. Target also has a brand new maternity line (that I can't remember the name of....) that had cute stuff as I walked by the other day. I think they have discontinued Liz Lange, so there are some good sales on that line if you like any of her stuff...I have a black trench coat from ASOS that I LOVE from my last pregnancy. I haven't browsed their selection in ages, though.

Gap was my go to for pants, the ones @LBEE linked to were my staple. Loft is great for tops.

I will also say that stitchfix maternity was fabulous. Definitely more expensive but unique items that could stretch your wardrobe between work and play. Highly recommend stitchfix for maternity!

It's expensive but I love Rosie Pope

Gap! And Old Navy.

Based on this thread I bought a pair of black seraphine pants (gap ones unfortunately don't work for me). While they aren't nearly as comfty as maternity work dresses, I'm really happy with how they look - like fashionable normal pants - and they should be a great staple.