The prevalence of congenital abnormalities in patients with positive contraction stress tests
Over a period of 10 years, 60,197 stress and nonstress tests were done in 25,313 patients. There were 229 (0.9%) positive tests. In 47.2% of patients who had positive tests, preeclampsia and hypertension were the indications for the test, followed by suspected intrauterine growth retardation (26.6%) (table I). The cesarean section incidence was 71%. The mean age of the patients was 32 years. Nine per cent of patients were 45 years or older, 7% between 40 and 44 years, 23% between 35 and 39 years, 30% between 30 and 34 years, 20% between 25 and 29 years, 7% between 20 and 24 years and 4% younger than 20 years. There were 13 intrauterine deaths of which 9 fetuses were regarded as too small to be delivered. Of the remaining 4 patients, intrauterine death occurred in 3 patients before cesarean section could be done and in the fourth a macerated twin was unexpectantly found when a cesarean section was done for fetal distress. Routine autopsies were not done on intrauterine deaths. The only external abnormality that could be found was an umbilical hernia. Apart from this abnormlity there were 9 liveborn babies with congenital abnormalities. Four of these babies died neonatally, bringing the perinatal death rate up to 50%. Four babies (1.7%) had chromosomal abnormalities. These were trisomy-21 in two patients, a trisomy-18 and a true hermaphrodite. Ages of the patients with the trisomy-21 were 46 and 49 years. Other abnormalities were exomphalos, microcephalus with hypospadia, hydrocele, polysyndactyly and hypospadia. One newborn had several congenital abnormalities including mitral valve atresia, malrotation of the colon, absence of one umbilical artery, a horse-shoe kidney and arrhenin-encaphaly. Although the incidence of chromosomal abnormalities was much higher than the general incidence in an obstetric population, it is porbably due to the high maternal age in the study (38% of patients were 35 years or older). They were probably selected because of their hypertension. As most of the babies who died neonatally were delivered by cesarean section one would have liked to make the diagnosis of the lethal congenital abnormality antenatally. However, antenatal diagnosis probably was only possible in the patients with the microcephaly and with the trisomy-18. Proper antenatal screening for trisomy-21 in the older patient should eliminate the problem of trisomy-21.