Is it normal that antidepressants change in effectiveness during pregnancy?

Discuss with U MD. Taking antidepressant during pregnancy can have negative effect on baby .U should avoid this unless u md recommend it.
Yes. With weight and hormonal changes one may need to adjust the dose during pregnancy. However i would caution against being on any antidepressants during pregnancy as most are classified as category c or higher in risk to the fetus. Please check with your doctor to weigh the potential benefits vs the risk before discontinuing.