4. Acute and chronic maternal health problems that can affect lactation. 4.1 Acute illness and infections: e.g. tuberculosis, Group B Streptococcus, Methicillin-Resistant Staphylococcus Aureus (MRSA), etc. 4.2 Alternations in endocrine and metabolic functioning: hypothyroidism, hypopituitarism, diabetes, Sheenhan's syndrome, gestational ovarian theca lutein cysts, polycystic ovarian syndrome. 4.3 Breast-related problems, e.g., breast surgery, injury, and cancer, etc. 4.4 Perinatal conditions: placental retention, dysfunctional uterine bleeding.