You dont have to
Universal recommendation is folic acid
, DHA and iron
to prevent deformity of brain and spinal cord of the baby and anemia
of mom. Calcium
is not needed if you eat/drink adequate milk and dairy products.
Taking extra calcium 500 mg/day is no harm, but you may be constipated from both iron and Calcium. Take Calcium few hours apart from other meds since calcium can bind with other meds.