Lawyers representing family planning groups yesterday argued before the U.S. Court of Appeals for the District of Columbia that Congress never intended that the government would notify parents whose teen-age daughters receive federally funded contraceptive devices.

In fact, attorney John W. Nields said, Congress in 1978 specifically rejected an amendment that would have required such notification. The confidential nature of the program was viewed as an asset in encouraging teen-agers to participate, he said.

The arguments came as the Reagan administration sought to overturn a lower court's permanent injunction barring what opponents call the "squeal rule" from going into effect. The rule requires 5,000 family planning clinics that receive federal funding to notify parents by certified letter within 10 days of the date when contraceptives are prescribed for a woman under 18.

A federal court in New York has similiarly barred the rule from going into effect.

Carolyn B. Kuhl, a deputy assistant attorney general, countered yesterday that Congress had intended such notification because it added an amendment in 1981 to encourage involvement by families in the process of obtaining contraceptives.

Nields said the amendment encourages participants, not the government, to inform parents.

Asked by Appeals Judge Harry T. Edwards if notification would undermine the program, Kuhl said there is no "scientific evidence" that it would. In any case, she said, the number of teen-agers who might be discouraged from using the program must be balanced against Congress' intent to encourage family participation.

Arguing that informing parents breaches the confidential relationship between patients and doctors, Nancy L. Buc, representing the Planned Parenthood Federation of America, said the government had brushed aside opposition to the rule from 40 states before putting it into effect Feb. 25.

Edwards, Judge J. Skelly Wright and Judge Robert H. Bork gave no indication of when they would rule.