The nation's obstetricians and gynecologists have not significantly changed their attitudes toward abortion in the past 14 years, and few oppose abortion under all circumstances, a new national survey suggests.

Eighty-four percent of the 1,300 ob/gyn specialists surveyed said abortion should be performed under some circumstances, while 13 percent said they would never perform an abortion (3 percent did not respond). The survey, conducted last spring by Needham Porter Novelli and Associates for the American College of Obstetricians and Gynecologists, is the first major survey of ob/gyn attitudes and practices in 14 years.

In the 1971 survey, 83 percent said abortion should be permitted at a patient's request or upon a doctor's recommendation, while 17 percent disagreed.

Among the 13 percent who refuse to do abortions under any circumstances, more than half said they refer patients who want an elective abortion to other doctors.

Of those who said abortions should be performed under some circumstances, more than 90 percent cited the woman's physical health, rape or incest, or fetal abnormalities as legitimate reasons for elective abortion in the first three months of pregnancy. Other acceptable reasons included: the woman's mental health (cited by 84 percent), the woman's personal choice (75 percent) and socioeconomic difficulties (71 percent).

Beyond the first trimester, the most frequently cited acceptable reason for an abortion was the woman's physical health (75 percent), rape or incest (68 percent), the woman's mental health (56 percent), socioeconomic difficulties (36 percent) and the woman's personal choice (36 percent).