This study examines how well antiretroviral (ARV) and anti-tuberculosis (TB) drugs work in pregnant women and after they give birth. **Pharmacokinetics (PK)** is a fancy word that means how drugs move through the body. The study is observational, meaning it watches people already taking these medicines as part of their regular care. It does not give out drugs. The study follows women and their babies for up to 24 weeks after delivery, depending on the group they are in. Pregnant women living with HIV who are on ARVs, with or without TB treatment, and new mothers who are breastfeeding, can join. The study involves regular visits for health checks and collecting samples to see how the drugs are working.

• **Study Duration:** Women and infants are followed for up to 24 weeks post-delivery.
• **Components:** Five study groups, each with specific drugs and conditions.
• **No Drug Provided:** Participants use their usual prescribed medication without changes.