539 births were to women aged 50 and older

Of 12,066,854 deliveries that resulted in live births or fetal deaths in the United States between 1997-1999 inclusive, 539 were to women aged 50 and older (four per 100,000). The sociodemograhic characteristics of pregnant women achieving pregnancy at 50 years and older are summarized in \l "TABLE1" and compared with the other age groups. Older mothers belonged to three broad racial groups. The overwhelming majority of them were white, with Asian or Pacific Islanders (main component of the group denoted as other) and black women constituting the rest.

Whereas the proportion of blacks among pregnant mothers declined with advancing age that of Asian and Pacific Islanders increased. Primiparity showed a roughly U-shaped pattern, being most frequent in the 20-29 age group, with a trough at the 40-49 age category, and another modest increase at 50 years and older. Great grand multiparity was most frequent among older mothers, twice the frequency in the 40-49 year old group.

The majority of women aged at least 50 years were married, had received at least 12 years of education, but surprisingly, only about half of them could be described as having utilized prenatal care services adequately. For cases where information was available, smoking and alcohol ingestion during pregnancy were relatively rare habits among older pregnant women in comparison with younger mothers.

Multiple gestations, on the other hand, were most frequent among 50-year-old mothers, comprising about one third of all deliveries in that age group. This rate for multiple pregnancy was seven times that of 40 year olds.