To a previous poster, I had a positive pregnancy test at 3 weeks pregnant. I missed my period, took a test, and knew the exact date I got pregnant, which was three weeks earlier. So your four week "fact" is incorrect.

For the OP, this is not the time to actively try to lose weight. But it's a great time to adopt a very healthy diet and a sensible exercise plan if your doctor okays it.

Pregnancy is not the time to cut calories to lose weight. Instead focus on moving your body, eating well (lean proteins, lots off veggies) and limiting pregnancy weight gain.

You maintain a workout program when pregnant, you don’t start it. Swim, walk, eat healthy… but don’t try to crash diet or start weightlifting now.

This is really not the time for drastic fat loss. Stay active, eat at maintenance and think about fat loss after you have delivered the baby.

You don’t know you’re pregnant until 4 weeks at the earliest and the first trimester is 12 weeks, so 8 weeks. It’s not safe to lose 20lbs in 8 weeks even when you’re not pregnant!

It is possible to lose maybe 5 lbs safely in that time, but NOT by calorie counting or restricting! You absolutely need to eat when you’re hungry when you’re pregnant!! But if you’ve developed some poor eating and exercise habits, and then start eating more healthy food, cutting out some junk, and exercising, you may drop a little. But if with those changes your weight may not budge, or may tick up, and you’ve got to be okay with that.

Are you for real? So you've been apparently overweight for a while but NOW is the perfect time to try to lose weight.

Solid plan. What could possibly go wrong?

No, you can’t lose weight but you can be in better shape, walk, swim, yoga, and yes eat well and drink lots of water.

Seriously? If you’re not a troll:

Safely exercise. Walk. Lift weights. Practice yoga. And EAT.

Don’t lose weight. Unless you want unnecessary medical testing and/or CPS checking on you. But, honestly, if you’re not a troll, from this question you may truly need therapy or other intervention.

No. This is not a good idea. Focus on eating healthy and moving more.

No. Focus on your baby. Walk a lot.

Losing weight is unlikely. Tightening up your core is also unlikely to be successful because your core gets compromised as the muscles make room and relax for your stomach. So you have to be careful what exercises you do.

However, as someone who exercised throughout pregnancy, appropriate cardio and exercise is a great idea. I kept up with many of my activites/classes, altering movements and moving off some activities if they didn't feel right. I also did some specific prenatal classes (which are designed for the weird stuff your body will do) and a lot of swimming. Keeping active really helped with my hip pain and sciatica which developed when I was pregnant.

So, yes to working out but realize your body's going to do funny things and you're more vulnerable to certain injuries.

No. If you are in your first trimester you are probably like 8 weeks right? Your belly will start expanding by 16.

I actually DID lose 20 pounds during this period. By vomiting 10-15 times a day. It was not safe. And would be impossible to replicate safely.

You can exercise and stay active and try to eat healthy while pregnant of course but the path might also lay itself out before you. I spent my first two trimesters lying around prone on the bathroom floor and my bed in between eating mcdonalds cheeseburgers and vomiting. Not much exercise or veggies happened!

You need to focus on weight loss after pregnancy. The most effective thing you can do is to try not to gain too much. That will make it easier to tackle weight loss and fitness after you have the baby.

I’m in my first trimester but I have a lot of weight that needs to go. Is it possible to lose 15-20 lbs (safely, with a trainer and nutritionist) and tighten up my belly before it stretches out?