Down’s syndrome (DS) is the most common form of intellectual disability. The syndrome is characterized by congenital malformations, especially of the heart and gastrointestinal tract, which can result in high mortality rates in the affected population. Many improvements have been made in the medical treatment of this syndrome during the past few decades and the survival of individuals with DS has increased in the industrial world. The aim of the present study was to investigate mortality in relation to congenital malformations. Medical records from all liveborn children with DS delivered between 1973 and 1980 in northern Sweden were studied, and malformations and causes of death were recorded. Out of the 219 children included in the study, a congenital heart defect was reported in 47.5% of subjects, 42.1% of whom had complete atrioventricular septal defect. Gastrointestinal tract malformations were present in 7.3% of subjects, and was frequently associated with a cardiac malformation and a very high mortality rate. Other major and minor congenital anomalies were present in 5.5% and 5.5% of subjects, respectively. In the 14.5‐year follow‐up of 213 children, the rate of survival was 75.6%. Mortality rates within one and 10 years after birth were 14.6% and 23.5%, respectively. Mortality within 10 years differed significantly between children with (44.1%) and without (4.5%) a congenital heart defect. A very high mortality rate was observed among children with a congenital heart defect, especially when it was combined with a gastrointestinal malformation.

At a group level, the presence of a CHD was the most important congenital abnormality in determining utilization of medical care and the burden of infections in the population of children with DS.

Survival in uncomplicated atrioventricular septal defect with common atrioventricular valvar orifice has greatly increased, and surgical correction is now equally successful in patients with Down's syndrome and chromosomally normal patients, and for both genders. Death in connection with surgery is no longer the major threat, and focus must now be on long-term follow-up.

Aims: To investigate maternal and neonatal factors in Down syndrome (DS) at birth, the impact of a congenital heart defect (CHD) on these factors and changes over time. Methods: Medical data of children with DS born in northern Sweden in the periods 1973–1980 (n= 219) and 1995–1998 (n= 88) obtained from the Swedish Medical Birth Register were compared. A comparison with the general population on a group level was also made. Results: The main finding was a reduction in infant mortality in DS, from 14.2% to 2.3% in 1995–1998 (p < 0.001), but this was still significantly higher than in the general population. The rate of Caesarean sections increased over time (from 14.5% to 27.3%, p < 0.05) even after adjustment for increased maternal age. No change over time was detected in the following rates: premature birth (gestational age ±36) (25%); asphyxia (5‐min Apgar score ±6) (8%); low birthweight (<2500g) (14%); or small for gestational age (SGA) (14%); all rates were significantly higher than those of the general population. A CHD did not seem to influence the rates of these factors in a logistic regression model. Conclusion: Infant mortality decreased substantially over time in the DS group, whereas there was no reduction in the rate of asphyxia, SGA, low birthweight or prematurity. The presence of a CHD did not influence any of the neonatal factors studied.