This study looks at how some medications work in pregnant women with HIV and tuberculosis (TB) and their babies. **Antiretroviral (ARV) drugs** help manage HIV, while **anti-TB drugs** treat tuberculosis. **Pharmacokinetics (PK)** is the study of how a drug moves through the body. This is an **observational study**, meaning researchers observe participants who already take these medications, without giving them any drugs themselves. The study has five parts, each focusing on different drug combinations and stages of pregnancy or after childbirth. Participants are followed for several weeks after delivery. The study won't provide any drugs but aims to understand how these drugs work during pregnancy and after. **Key Points:** - **Duration:** Participation can last up to 24 weeks after delivery. - **Visits:** Involves multiple check-ups and sampling visits. - **No Medication Provided:** Participants must already be on ARV or TB medications through their healthcare provider. This study is crucial for understanding how these medicines affect pregnant women and their babies, ensuring their safety and effectiveness.