Others have normal or above average intelligence. The most widely-quoted estimate of FAS incidence in North America is one per 3000 live births. However, the incidence goes up significantly in some parts of the population. Most researchers agree that the incidence of other alcohol-related birth defects is much higher, but difficulties in diagnosis make it impossible to say precisely how much higher. Whether there is alcohol-related damage, and what kind of damage there will be from maternal alcohol use depends on many factors.
Different injuries happen at different stages of gestation.
In general, lower levels of alcohol consumption tend to produce milder effects. No safe level for drinking during pregnancy has been established, however. Alcohol use may even damage eggs before pregnancy occurs. Because this issue of Developments is aimed primarily at those who work with addictions, this introduction focuses on the worst consequences of prenatal alcohol exposure. However, in the past three decades, people who work with FAS have come to a gradual understanding that much can be done to improve the lives of those affected by the behavioral symptoms typical of FAS, especially when there is early diagnosis.