5. 1st Trimester PRE
Many yoga disciplines do not recommend anything other than breath work, meditation, walking and possibly limited seated asanas at this stage.
Reason being that the body is working hard to properly implant the embryo(s). Having suffered multiple miscarriages, I know the heartache intimately and is why I now strongly recommend no training during the delicate 1st trimester.
Certain movements: twisting, extensions, forward flexion with compression, even standing in ballet 2nd, (especially a grand plie in 2nd), can result in implantation problems and/or miscarriage as the uterine lining is being thinned.
If you have a history of miscarrage(s), please just do breath work, meditation + walking. There is a special IN 10 ALLONGE created for 1st Tri Prenatal that is safe, but that is all I can recommend in good conscience.
If you choose to workout at this point, do so at your own discretion, but please do not use any weights whatsoever, no HIIT/cardio and listen intently to your inner body cues.
To reiterate: i do not recommend training during the first trimester.