Pan American World Airways has agreed to pay up to a total of $89,000 in back wages to as many as 390 ground workers who claim the airline forced them to take maternity leave after seven months of pregnancy.

Under the settlement approved yesterday by U.S. District Court Judge Harold Greene, the ticket agents and clerks could get as much as $970 -- five weeks of pay at $194 a week, the average Pan Am ground worker's wage from 1970 to 1973, the period of the disputed maternity leaves.

The airline disputed the claim that it forced the women to quit work after seven months of pregnancy. But until October 1973, Pan Am had no written policy, as it does now, stating that women may work as long as they are able before giving birth.

Under terms of the settlement, women wishing to collect the back pay will simply have to state that at the time they started their pregnancy leave, they wanted and were able to continue working and that they quit early under the belief they had to because of the airline's maternity policy.

A total of 236 of the 390 women affected by the settlement have been located, while new efforts are being made to find the remaining 154 women who may be entitled to make a claim, according to court papers in the case.

The case was brought in October 1973, by Jane Margaret Macobs and Candace Johnson Harshaw. They were represented by the Lawyers Committee for Civil Rights Under Law.