The legal bills for lawsuits over the Dalkon Shield contraceptive device wiped out 99 percent of the quarterly profits of A. H. Robins Co., the Richmond pharmaceutical company reported yesterday.

Robins' sales for the quarter were the highest for any three-month period in its history: $157.3 million, up from $144.7 mllion in the same period a year ago.

But after paying legal bills, Robins' profits amounted to only $200,000 (1 cent a share), down from $14.8 million (61 cents) a year ago. The company said it spent $13 million defending itself against liability cases filed on behalf of women who were injured or injured by the interuterine device.

President E. Claiborne Robins Jr. said the company is studying creating a special reserve fund to pay legal costs and settlements of Dalkon Shield cases. He said Robins expects "significant charges to income" will contunue until the Dalkon Shield matter is settled. As of June 30, 7,400 lawsuits have been settled or disposed of by the courts at a cost to Robins and its insurers of $233 million.

For the first nine months of 1984, Robins' profits were off 54 percent to $20.2 million (80 cents) from $44 million ($1.81), even though sales climbed to $465.6 million from $418.1 million.

Genex Corp. reported its first quarterly profit Friday, but predicted a net loss in the fourth quarter because of "substantially lower" product sales.

The Rockville biotechnology firm provided no explanation for the predicted sales decline, and "the lack of detailed information coming in the atmosphere of a nervous market" caused its stock to close down 2 1/4 at 7 5/8 in national over-the-counter trading Friday, said Nelson M. Schneider, a biotechnology analyst with E. F. Hutton & Co. Inc. The stock lost another 1/8 yesterday to close at 7 1/2.

Genex, founded in 1977, said a special $6.9 million payment was responsible for its third-quarter profit of $3.7 million (29 cents). Genex lost $658,000 (5 cents) in the same period of 1983.

In the first nine months of this year, Genex earned $79,000 (1 cent) compared with a loss of $3.7 million (30 cents) the year before.

The firm, which produces an enzyme-based drain cleaner and the amino acids used in the low-calorie sweetener aspartame, reported third-quarter revenue of $19.3 million, up from $3 million in the same quarter of 1983.

Revenue increased to $33.5 million in the first nine months of the year from $6.4 million.

Product sales increased to $10.7 million in the third quarter from $2,000 in 1983. Fourth-quarter product sales, however, will be "nowhere near as high," a Genex spokeswoman said.

Genex attributed its third-quarter profits to a $6.9 million settlement payment from Allied Corp., which terminated a research and development project with Genex in July.