Is it safe for me to lift my other children while pregnant?

Yes: Yes, as long as you do not have an incompetent cervix or other conditions that require low pressure conditions, such as pulmonary hypertension or arterio-venous malformations (avms) to name a couple.

Yes: In an otherwise uncomplicated pregnancy, this should not be a problem. Certainly gets harder in the later stages and things like incompetant cervix might change that answer. Ask you obstetrician about any liftng restrictions specific to your situation.