What is the need of nursing bra? Should we actually buy a separate bra for that time??

The answer is yes.

Traditional bras don’t have room for the diaphragm to grow during pregnancy and they also have a traditional underwire which is not recommended to wear whilst pregnant or nursing. It’s important to use bras that have soft cups and have increased rows of hooks and eyes. This allows your bra to have room for the diaphragm to expand during the months of pregnancy and the ability to tighten after the baby is born and the diaphragm settles. It also means you’ll be comfortable and have a beautifully support. Having wider straps on a maternity bra is also important for support, especially for larger cup bras. This is definitely something to look for when choosing a nursing bra. Comfort is critical specially when breastfeeding.
Wearing underwires are definitely not recommended for pregnant or breast feeding ladies.
Underwire bras place pressure on the milk ducts and soft, tender tissue, potentially blocking milk flow and leading to plugged milk ducts. This may lead to bad infections requiring antibiotic treatment, which can interrupt the breastfeeding routine. Most maternity bras are technically designed to give you all the support you need.
As important as the fit is the support and practicality. It’s also important that you look and feel feminine, sexy and empowered. Pregnancy and being a new mother can be challenging and wearing plain lingerie certainly doesn’t lift the spirits.
So chose a nursing bra that makes you feel good and happy..
Such are nursing bras from morphmaternity .
These have breathable cotton fabric for maximum support and comfort , leak-proof , so no more embarassing breast-milk leaks in public. Made of 100% breathable fabric, so very comfortable. Drop cup for easy nursing featuring one handed access and rear closure with adjustable hook & eye..

A must have for nursing, you can buy them from
MorphMaternity.com

https://www.morphmaternity.com/maternity-lingerie/leakproof-nursing-bras.html