CooperSurgical, a major medical supply company, is facing a wave of lawsuits from patients who claim that one of its products destroyed embryos created with in vitro fertilization.

Fertility clinics across the world used the product, a nutrient-rich liquid that helps fertilized eggs develop into embryos. This week federal regulators made public that the company had recalled three lots of the liquid, which was used by clinics in November and December. The number of affected patients is unclear, although experts estimated that it is in the thousands.

On Thursday, a couple in Virginia filed a lawsuit against the company, the eighth in two months from families around the United States. Collectively, the patients say they lost more than 100 embryos that had bathed in the defective product, known as culture media.

The plaintiffs claim that the three batches of media were missing a key nutrient, magnesium, a defect that stopped their embryos from developing and rendered them unusable.

The company declined to comment on the lawsuits.

The Food and Drug Administration posted a recall notice on Wednesday saying that nearly 1,000 bottles of culture media were affected, about half of which were purchased by clinics in the United States. The filing said that the company had notified affected clinics on Dec. 13, telling them that “performance issues may lead to impaired embryo development” and instructing customers to stop using the product.

Each bottle holds enough liquid for multiple patients, though it’s unclear how many bottles were opened before the December recall. If clinics used even half of the affected bottles, as many as 20,000 patients could have been affected, said Mitchel C. Schiewe, an embryologist and a laboratory director at California Fertility Partners, which he said briefly used the botched media in November.

Fertility medicine is a relatively new field with limited oversight from federal regulators. With demand for IVF climbing, CooperSurgical has raced to position itself as an industry leader. Over the past decade it has acquired five smaller fertility companies.

CooperSurgical brought in $1.2 billion in revenue last year, with 40 percent of that coming from its fertility services and supplies. The firm owns large sperm and egg banks and sells genetic tests to ensure that embryos are healthy.

In a January call with investors, the company’s chief executive noted that the company had achieved 12 straight quarters of “double-digit growth” in its fertility business.

The eight lawsuits describe a similar pattern of events. Couples had struggled for years to conceive. Many learned they had created healthy embryos around Thanksgiving, only to hear by Christmas that the embryos had suddenly stopped growing.

The first lawsuit involved a Los Angeles couple who claim that 34 embryos were destroyed by the defective media. Their lawyer, Tracey Cowan, said that the case represented a recent trend in manufacturing problems, the result of rapid growth and consolidation in the companies supplying the fertility industry with everything from freezers and pipettes to embryo media.

“Ten years ago, most of my cases were all clinic negligence,” said Ms. Cowan, a partner at the Clarkson Law Firm who has filed five cases related to the CooperSurgical liquid. “It’s only recently, in the last few years, that we’ve started to see a lot more of these product recall cases.”

In the newest case, brought by the Lieff Cabraser Heimann and Bernstein law firm, a couple from Virginia described a decade of painful efforts to conceive before turning to in vitro fertilization last fall. After adopting their son six years ago, the couple, Kearsten and Zachary Walden, were elated to discover last summer that Mr. Walden’s insurance plan had added fertility coverage.

They quickly scheduled an appointment with a local fertility clinic, and an initial round of treatment yielded six fertilized eggs. The Waldens were optimistic, they said in an interview, until they received a phone call Thanksgiving morning, notifying them that all of the embryos had stopped growing.

“I very much blamed myself, being older,” said Mrs. Walden, 39, who works in marketing in Norfolk, Va.

She began researching how she could produce healthier eggs on her next round, the last one that would be covered by her husband’s insurance. In January, her clinic notified her that they had used the defective CooperSurgical media on her embryos.

“It was a roller coaster of emotions,” Mrs. Walden said. “It was, wait a minute, so we’re not at fault, and not to blame. Then it was, how does something like this happen?”