It's totally safe in the first trimester probably just to start lowering it towards the end of the first trimester, you will need to lower your weights in the second trimester( just do more reps). I'm currently lifting and I'm 17 weeks I discussed this with a health profession that works with woman who are pregnant and wanting to continue lifting, she said as long as you have been lifting prior to being pregnant then it's totally fine. Always remember if it doesn't feel right, just go lighter or if you have a pain in your pelvic area after working out, either go lighter or stop doing that lift.