Image copyright Getty Images Image caption J&J says it defends the safety of its baby powder product

Pharmaceutical firm Johnson & Johnson (J&J) has been ordered by a US court to pay more than $110m (£85m) to a woman who says she developed ovarian cancer after using its talcum powder.

Lois Slemp, 62, from Virginia, Missouri said she developed the cancer after four decades of using talc products.

Prosecutors argued the company did not adequately warn about the cancer risks associated with the items.

Experts say links with ovarian cancer are unproven. J&J says it will appeal.

The verdict in a St Louis state court is the largest so far to arise out of about 2,400 lawsuits against J&J over its talc-based products, Reuters news agency reports.

Ms Slemp is currently undergoing chemotherapy after her ovarian cancer initially diagnosed in 2012 returned and spread to her liver.

She said the products she used included J&J's Baby Powder and Shower to Shower Powder.

"Once again we've shown that these companies ignored the scientific evidence and continue to deny their responsibilities to the women of America," said Ted Meadows, a lawyer for Ms Slemp.

The verdict included $5.4m in compensatory damages and $105m in punitive damages against J&J.

The company said it planned to appeal. "We are preparing for additional trials this year and we continue to defend the safety of Johnson's Baby Powder," it said in a statement.

"We deeply sympathise with the women and families impacted by ovarian cancer."

J&J lost three jury verdicts last year in cases related to its talc-based products, but won its first trial in March, when a jury in Missouri sided with the company.

Is talc safe? James Gallagher, health editor, BBC news website

There have been concerns for years that using talcum powder, particularly on the genitals, may increase the risk of ovarian cancer.

But the evidence is not conclusive. The International Agency for Research on Cancer classifies talc used on the genitals as "possibly carcinogenic" because of the mixed evidence.

Why is there any debate?

The mineral talc in its natural form does contain asbestos and does cause cancer, however, asbestos-free talc has been used in baby powder and other cosmetics since the 1970s. But the studies on asbestos-free talc give contradictory results.

It has been linked to a cancer risk in some studies, but there are concerns that the research may be biased as they often rely on people remembering how much talc they used years ago. Other studies have argued there is no link at all and there is no link between talc in contraceptives such as diaphragms and condoms (which would be close to the ovaries) and cancer.

Also there does not seem to be a "dose-response" for talc, unlike with known carcinogens like tobacco where the more you smoke, the greater the risk of lung cancer.

What should women do?

The charity Ovacome says there is no definitive evidence and that the worst-case scenario is that using talc increases the risk of cancer by a third.

But it adds: "Ovarian cancer is a rare disease, and increasing a small risk by a third still gives a small risk. So even if talc does increase the risk slightly, very few women who use talc will ever get ovarian cancer."