Hormone health risks highlighted by landmark US court case

The daughters of women who took the synthetic oestrogen diethylstilbestrol during pregnancy had a higher risk of suffering infertility, premature childbirth, breast cancer and a rare cancer. File photo / Thinkstock

Hundreds of New Zealand women could face the same health risks as a group of United States women taking a landmark court case against the manufacturers of a dangerous synthetic hormone, an Otago University expert warns.

A US study last year found the daughters of women who took the synthetic oestrogen diethylstilbestrol (DES) during pregnancy had a higher risk of suffering infertility, premature childbirth, breast cancer and a rare vaginal cancer, clear cell adenocarcinoma (CCA).

Now a group of 53 daughters of US women given the hormone during pregnancy are suing 14 of its manufacturers.

It is the first court case to allege a link between DES and breast cancer.

The hormone was given to some pregnant New Zealanders in the 1960s in the mistaken belief it could reduce complications, but has not been prescribed here since 1971, when the hormone was discontinued.

Otago University's Professor Charlotte Paul, a preventive and social medicine expert who was medical advisor to the Cartwright Inquiry into cervical cancer, said hundreds of New Zealand women were given the hormone before it was discontinued.

But the exact number remains "a guess" after health authorities in the 1980s refused her request to set up a register of those who were potentially exposed.

The only figures come from a survey of obstetricians and gynaecologists that Ms Paul and her colleagues carried out in the early 1980s.

"We estimated 600 exposed women in 1984 and considered that a major underestimate. It may be 1000 to 2000. It is a guess now," she said.

Ms Paul wrote a paper in 2006 in which she said the long-term adverse effects of prescribing DES to pregnant women in New Zealand were yet to become clear.

"The mothers have an increased risk of breast cancer, the daughters of CCA and breast cancer, and very commonly structural abnormalities of the reproductive tract and hence difficulty with childbearing. The sons have some reproductive tract abnormalities," she said.

The US research found exposed daughters were twice as likely to be infertile, five times as likely to give birth prematurely, and had 40 times the risk of developing CCA compared with women not exposed in the womb.

A pre-trial hearing in the US court case was due to wrap up in a Boston court today.