Progesterone injections, extremely dangerous

Feb 12, 2007 14:27 GMT  ·  By

Miscarriages are often the result of a genetic disorder. Sometimes, they are triggered by uterus abnormalities, unbalanced hormonal levels, clotting impairments or lupus in the mother. "But in at least half of the cases, we can't find the reason. It's frustrating," says Mark Walker at the University of Ottawa in Canada, who was not involved in the study.

A new research carried on at the Sheba Medical Center in Tel Hashomer, Israel, might have shed some light on the origins of these unexplained miscarriages. The scientists found - in the case of women with recurrent miscarriages - an immune hypersensitivity to female sex hormones (that regulate pregnancy), estrogen and progesterone, in skin tests.

This is a warning signal, as some controversial current therapies against miscarriages include progesterone injections. "Previous studies had shown a connection between miscarriage and unusual immune system responses, but none had looked at the role of these sex hormones," the researchers say.

The team injected the hormones into the skin of 29 women who had suffered at least three unexplained miscarriages, and 10 women who had successfully gave birth to a healthy, normal baby and never experienced a miscarriage. 26 women in the first group showed immune hypersensitivity to one of the two hormones, and 17 of them were hypersensible to both, while the women that had not experienced miscarriage were totally immune. "This is really novel," says Walker. "It's a small sample size but if the results are that profound, it definitely warrants more research."

"It opens prospects as far as diagnostics and treatment," says Alek Itsekson, who led the study. "Hypersensitivity to these hormones might be increasing the numbers of immune system cells called natural killer cells."

These immune cells normally gather around the embryo as it develops, but a rise in their number has been connected to early miscarriage. Steroids were checked as a possible treatment for this condition, but they can trigger harmful side effects. "Knowing the mechanism behind the negative immune reaction to progesterone and estrogen might lead to better options," the researchers say.

Further investigations made on rats will explain more details about this phenomenon. The finding is a warning signal towards therapies involving progesterone injections to women possessing low progesterone levels. "The usefulness of these injections is already controversial, the researchers say, and if the women are hypersensitive to progesterone the treatment may have unknown side effects," the researchers said.