Columbia subject headings:
Childbirth--United States--Statistics--Periodicals.
Fertility, Human--United States--Statistics--Periodicals.
Harvard subject headings:
Childbirth--United States--Statistics--Periodicals.
Fertility, Human--United States--Statistics--Periodicals.
Princeton subject headings:
Childbirth--United States--Statistics--Periodicals.
Fertility, Human--United States--Statistics--Periodicals.
Periodicals.
Statistics.