I am breastfeeding, and my newborn is now in his 4 month, can i fast during ramdan when my baby begins his 6 month?

Stay well nourished: Most physicians and imams would recommend that you stay well nourished and hydrated while breastfeeding to protect the health of you and your baby. Consider honoring Ramadan by taking a "fast" from television or shopping or give a special zakat to needy families in your community.

Yes: Your body will continue to make quality milk in spite of fasting, and will extract needed nutrients from your body creating a deficit if you don't replace them during your non-fasting intervals. Keeping the faith does not hurt the babies.