ST. PAUL, MINN., FEB. 2 -- A lawsuit alleging that the Copper-7 intrauterine device resulted in a woman's infertility will proceed to trial following a judge's ruling that evidence about potential health risks may have been concealed.

U.S. District Judge Robert G. Renner on Monday refused to dismiss a product liability suit against G.D. Searle & Co. of Skokie, Ill., brought by Esther R. Kociemba and her husband.

The $1 million lawsuit alleges the Copper-7 birth control device resulted in infertility, illnesses and "great pain and suffering and mental anguish."

Kociemba is one of hundreds of women across the country who claim that using the Copper-7 device resulted in infertility. The women claim a defective tail string on the IUD caused infection.

The Kociembas' lawsuit, one of 800 filed nationwide against Searle, would be the first to go to trial using new evidence uncovered about the product, said attorney Michael V. Ciresi of the firm that represents Kociemba and more than 100 other women suing Searle.

Searle has repeatedly denied the allegations against the Copper-7, which was used by an estimated one million women since it was approved by the Food and Drug Administration in 1974. It was withdrawn from the market two years ago because of mounting lawsuits and liability costs, said Searle.

Seventeen suits against Searle had gone to trial as of October 1987; Searle lost three of those. Two were settled and Searle is appealing the third.

In responding to Searle's argument that a four-year statute of limitations bars the claim, Renner said the plaintiffs "produced extensive evidence supporting allegations that Searle concealed information that, had it been known earlier, would likely have caused" the suit to be filed earlier. Kociemba began using the device in 1977.

Renner is expected to decide soon whether to order the public release of confidential corporate documents said to describe the allegedly defective nature of the product.

The trial is tentatively set to begin in April.