• Rubella
    The recognition that the live virus of German measles persists in the fetus as a cause of permanent abnormalities opened up a new chapter in the study and prevention of birth defects. The association was brought to light by an Australian ophthalmologist, who recognized an unusual frequency of congenital cataracts in newborns during a time of an epidemic of rubella (Gregg, 1941). Soon the additional cardiac defects of patent arterial duct and peripheral pulmonic stenosis were also found to be linked to this infection (Rose 1972, Rowe 1978). The development of immunization programs to include rubella immunity has virtually eliminated this major teratogen in developed countries. No case occurred in the BWIS.
  • Influenza
    A maternal history of possible influenza in the earliest weeks of pregnancy would be difficult to evaluate but was searched for in the Baltimore Washington Infant Study (BWIS). Only a single defect, transposition of the great arteries with intact ventricular septum, revealed a 2-fold statistical excess of such a history, but the odds were increased to 5-fold in the presence of ibuprofen treatment. These findings are based on small numbers, but are worthy of further attention, as this is a unique malformation with very few other associations.
  • Maternal diabetes
    In pre-insulin days women with diabetes were seldom able to bear children but with insulin control they have achieved a normal life course, and successful pregnancies. However their infants are at risk for malformations of the cardiovascular, renal and central nervous systems. Recent advances in the care of high-risk mothers with better control of blood sugar levels has reduced the risk to population levels under close obstetrical care. A major problem remains in women, who are not aware of their diabetic status and present for maternity care too late to institute an adequate level of blood sugar control during the earliest susceptible period of pregnancy (Reece EA 1996, 1998).

    In the Baltimore Washington Infant Study (BWIS), maternal diabetes was found to be specifically associated with certain cardiac defects: a 3-fold risk for all cases (excluding chromosomal and other genetic conditions) was increased to 4.7- fold for early CVM , and to 23-fold for cases with complete, but not partial, atrioventricular septal defects (Loffredo 2001). There was also a 12-fold increase in the risk of maternal diabetes for cases of early CVM with associated non-cardiac abnormalities . Low birthweight and prematurity were responsible for an increased mortality in the first year of life (Loffredo 2001).

  • Maternal phenylketonuria
    No infant in the BWIS had a history of maternal phenylketonuria but the occurrence of severe cardiac defects has been reported in infants whose mothers had phenylketonuria and had been raised on low phenylalanine diets. These mothers had relaxed their attention to their diets prior to pregnancy. This is a remarkable story of the success of a public health program with failure of its long-tem completion (Pass, 2000).

Selected References