Nazi Medical Myth Debunked:

Ear physicians were taught for decades that otosclerosis is made progressively worse by pregnancy and can lead to hearing losses or deafness in the expectant mother. Thus doctors often told women with the condition not to get pregnant, and as late as 1950, having otosclerosis was a reason for abortions in many countries, including Israel. The condition has been treatable since the 1960s, thanks to stapedectomy – surgery that restores flexibility to the damaged ear bone. Hearing aids can also benefit patients who do not have surgery.

Lippy, who spent extensive time working and teaching in Israel and was a visiting professor at Jerusalem's Hadassah-University Medical Center, said he began to suspect that 'common medical knowledge' regarding otosclerosis was untrue when he observed that many of his female haredi patients with otosclerosis who had numerous pregnancies did not have any worse hearing than the women who were childless. Upon investigation, he discovered that the original 'correlation' between pregnancy and otosclerosis came from a paper written by eight German physicians in 1939.

The findings in this paper were far from conclusive: Only two really believed that otosclerosis was really speeded up or worsened by pregnancy, Lippy said.
Jerusalem Post - Israeli study disproves Nazi myth