Is a ginger capsule the same as cooking with ginger?
No, it is considerably more concentrated. That is the reason the capsules exist, and there is no reason not to do both.
Capsule or tincture?
Capsules are simpler and consistent. A tincture is the traditional liquid extract and a bottle lasts a long time.
Can I take ginger with anticoagulants?
Ask your GP or pharmacist first. Concentrated ginger is a different proposition from the amount used in cooking.
Is it suitable during pregnancy?
Speak to your midwife. It comes up frequently in that context and is worth asking about rather than assuming.