Well I was the same as you. I was 127 kgs when I had dd1 at 38 weeks gest. I felt shocking by the end of my pregnancy. After I had her my weight just kept going up until I was 167kgs eekkk . I started on duromine to help me to lose the weight. I managed to get down to 124 kgs before I fell preg with this bubby.
We did not mean to fall pregnant so quickly and really thought it would take at least 6 months as it took us 3 yrs and clomid to get dd1. So there we were with me pregnant and weiging in at 124 kgs.
The hospital have been fairly good about it. I'm now 23 weeks pregnant and weighing in at 127 kgs but I feel really good this time around.
I think do whats right for you however please do realise that the hospital will put you in the high risk catogory due to high BMI and they will also want to do a GTT test at about 23 weeks preg, Other than that my weight has been left up to me.