One of my favourite core exercises that I do regularly myself and also with my PT prenatal and postnatal clients is the Palloff Press.
This is an anti-rotational exercise where you use your deep core muscles to fight the rotation of being pulled to the side. It’s a perfectly safe exercise to do when you’re pregnant and also if you’re postnatal. It’s usually a good one to do if you’ve got a diastasis recti although if you find you’re experiencing ‘doming’ or ‘coning’ down the middle of your abs then it’s probably a little too advanced for you at the moment.
Your breathing is so important. Make sure you breathe in before you start, holding the band in clasped hands up against your sternum. As you breathe out take your arms straight out in front of you, whilst engaging your core (drawing your belly button in and up or imagine drawing the front of your hip bones together.)
The further away you stand, the tighter the band, the harder the exercise.
All you need is a resistance band. Try 10 on each side for 3 sets. Give it a go and let me know!