PIP: A prospective study was carried out to determine the incidence and nature of retained products of conception following legal abortion before the 20th week of pregnancy. Placental tissue was retained in 13 out of 39 cases in the 1st trimester. Ultrasound was used during the procedure to aid evacuation of retained products in 3 cases. Fetal parts were retained in 3 of the remaining 11 patients in the 2nd trimester of pregnancy. The finding of a 33% rate of retained products in the 1st trimester is higher than other estimates obtained when complications such as hemorrhage or infection occurred, necessitating uterine exploration. It is probable that in many cases retained products do not cause significant complications and are passed spontaneously through the vagina. It is interesting to note that, of the 4 cases where products were retained during the 2nd trimester, 2 involved retention of the fetal head. It is suggested that ultrasound screening of the uterine cavity at the end of the 2nd-trimester abortion procedure represents a better method of confirming completeness of evacuation than the reassembling of fetal parts. Routine use of ultrasound during dilatation and evacuation also has the potential to reduce the morbidity associated with induced abortion.