By Alice Dreger, The Atlantic, Jan 16, 2013
When Susan Manning, a 39-year-old woman just a few weeks into her first pregnancy, wrote to tell me she had been put on the steroid dexamethasone to prevent a miscarriage–and to ask whether she should be worried about taking this drug–at first I could not even process what she was saying. Dexamethasone is known to cross the placental barrier and impact fetal development, so the very idea of first trimester exposure sets off warning bells. Besides, dexamethasone is not known to help in preventing miscarriage. Susan’s story sounded too crazy to be true.
It also sounded too close to the history of DES (diethylstilbestrol). From the 1940s through the 1970s, some doctors gave pregnant women DES, a synthetic estrogen, to try to prevent miscarriage. In spite of clinical evidence that it didn’t work as intended, millions of fetuses were exposed in utero before doctors discovered that prenatal DES exposure could lead to infertility and deadly cancers. Just last week, Eli Lilly & Co. settled a suit brought by four sisters who believe their breast cancers were caused by prenatal DES exposure.
But as it turns out, Susan (a pseudonym) had it right. Women like her, pregnant by virtue of in vitro fertilization (IVF), are today routinely put on dexamethasone for miscarriage prevention at some IVF clinics. Susan is being treated abroad at a high-profile clinic, but some American infertility clinics also advertise this off-label use of dexamethasone as if it is the standard of care.
I inquired about this with Dr. Geoffrey Sher, Executive Medical Director of the Sher Institutes for Reproductive Medicine, a high-profile infertility practice with offices across the country. He confirmed in an email that, “We recommend 0.5 mg – 1.0 mg. [of dexamethasone] orally daily (dosage varies based upon individual patient needs) from the time of initiating the [IVF] cycle through to the tenth week of pregnancy.” He could not point to studies showing that dexamethasone helps prevent miscarriage, but argued, “Since there are so many other variables that are involved” in IVF pregnancies, studies “would virtually be impossible to do…”