The state of health care is reflected by perinatal and neonatal morbidity and mortality as well as by the frequencies of long-term neurologic and developmental disorders. Many factors, some without immediately rec­ ognizable significance to childbearing and many still unknown, undoubt­ edly contribute beneficially or adversely to the outcome of pregnancy. Knowledge concerning the impact of such factors on the fetus and sur­ viving infant is critical. Confounding analyses of pregnancy outcome, especially these past two or three decades, are the effects of newly un­ dertaken invasive or inactive therapeutic approaches coupled with the advent of high technology. Many innovations have been introduced with­ out serious efforts to evaluate their impact prospectively and objectively. The consequences of therapeutic misadventures characterized the past; it seems they have been replaced to a degree by some of the complications of applied technology. Examples abound: after overuse of oxygen was recognized to cause retrolental fibroplasia, its restriction led to an in­ crease in both neonatal death rates and neurologic damage in surviving infants. Administration of vitamin K to prevent neonatal hemorrhagic disease, particularly when given in what we now know as excessive dos­ age, occasionally resulted in kernicterus. Prophylactic sulfonamide use had a similar end result. More recent is the observation of bronchopul­ monary dysplasia as a complication of respirator therapy for hyaline membrane disease.