Hey mama, I'd really suggest checking with your OB-GYN about this one kasi ang timing ng pagstart ng birth control pills, especially on first day ng period, it's something na personalized depende sa brand at your specific health situation, at ang Daphne specifically ay may particular instructions na basta dapat i-follow ng doctor mo! You're being so proactive about understanding your options, which is great, your doctor will be able to walk you through exactly when to start and what to expect sa first few days, especially if you're breastfeeding pa, kasi may considerations doon. You've got this, at you're doing the right thing by asking before you start!