This study presents a geometric development of functional clothing (for pregnant women). In the beginning, we discuss the main changes women's bodies undergo during pregnancy and the requirements of an adequate wardrobe. Using specific design tools (Gemini CAD – a Lectra Company), we develop a geometric network for designing made-tomeasure maternity clothes (case study – blouse). From this network, three specific blocks have been developed in accordance with the body changes. The estimated increments of the second and third pregnancy trimesters have been expressed as correspondent angles and used to design the adequate shape of the blouse patterns (front and back). We have also evaluated the blouse patterns when dressed on the corresponding avatars for each trimester via 3D simulations.