has part has part has_part characteristic of has modifier mammary gland branching involved in pregnancy abnormal mammary gland development abnormal mammary gland growth during pregnancy anomaly in the extensive and rapid branching of the mammary ducts, expansion of mammary epithelium in the stroma between the ducts with or without abnormalities in nipple maturation in preparation for lactation MP:0006269 MPheno.ontology abnormal pregnancy quality abnormal