trying to lose weight while pregnant?

I'll def talk to my midwife too but wanted to get opinions from you. I am 6 months pp and 9 weeks pregnant and I am still up about 15 pounds from my pre pregnancy weight. I was trying pretty hard to lose that when I got pregnant. Is it safe to continue to try to lose a little weight now that I'm pregnant? It would be great if I didn't gain anything until 6 months or so...kind of balance out. By the way I am not considered to be overweight. I am 5 foot 7 and am 151 pounds right now. Pre pregnancy weight was 137(ish)