Weight lifting
You can be a fitness freak or a gym lover. You can continue your exercise routine absolutely without weights. Lifting anything heavy during this time can put pressure on your back and pelvis. Avoid carrying heavy things, even at home.
Sauna
We all like to go to relaxing sauna sessions once in a while. It helps to reduce stress, relaxes and refreshes us. However, exposing yourself to such high temperatures while pregnant is absolutely harmful.
Running
If you have been involved in jogging all your life, you can continue this activity throughout your pregnancy with your doctor's approval. However, it is not recommended to start running while pregnant. A better alternative might be walking. It is easier and the risk of losing control of your body is much lower than running.
Bicycle
Cycling is a completely bad idea for expectant mothers. Even for those who are experienced, it is only recommended until the second trimester, as the center of balance of the body changes due to belly growth. While even walking itself seems difficult at this point, cycling is out of the question. Also, in open lanes and heavy traffic areas, you don't want to risk yourself and the baby.