Several studies1 have shown that Zoloft has a low risk of passing into breast milk in significant amounts. The American Academy of Pediatrics3 (AAP) states that Zoloft is compatible with breastfeeding and can be used when needed.
Zoloft belongs to a class of medications called selective serotonin reuptake inhibitors (SSRIs), commonly used to treat depression and anxiety. It's been extensively studied, and the consensus is that the benefits of breastfeeding often outweigh the potential risks associated with taking Zoloft.
However, it's always a good idea to consult with your healthcare provider before starting or continuing any medication while breastfeeding.