Undeveloped arm/leg. Phocomelia occurs when the limb buds (arms & legs) are interrupted in fetal development & one or more do not form. In some countries, thalidomide was used for nausea in pregnancy. If taken between week 4 and 7 (when the limb buds come out) up to 30% of exposed infants were affected. This experience led to the largest us study of meds in pregnancy with > 50, 000 studied.