As per a private analyst who combed through the public database of the US Food and Drug Administration, the agency has probably greatly underestimated the number of fetal deaths in women who got pregnant after using Bayer AG's Essure contraceptive device.

The FDA has mentioned five fetal deaths in women who conceived with the help of Essure, two metal coils put into the fallopian tubes.

A spokeswoman for Bayer said, “Irrespective of the type of birth control a woman uses, when pregnancies do occur, there can be complications. It would be irresponsible to suggest that Essure causes fetal deaths when, after an unsuccessful Essure procedure, an undesired pregnancy cannot be carried to term”.

Madris Tomes, founder and chief executive officer of Device Events, said that her analysis of thousands of bad events from the website of the agency has shown that 303 fetal deaths were related to Essure.

This month, the agency is expected to take a decision over whether to limit use of the device, alter the label of the product or suggest extra clinical trials. The agency has also cited four adult deaths caused by issues such as infection and uterine perforation.

Tomes said that the difference on fetal deaths between the FDA count and her own was due to the reason that the agency look for wide headings of bad event reports that it receive from patients and doctors rather than looking for the thorough texts of such complaints.

Tomes added that when adverse events go to the agency, 'death', 'injury' or 'malfunction' are the boxed checked by them. And, her system looks for the fuller narrative, with the help of keywords like 'fetal death', 'stillborn', 'miscarriage' and 'stillbirth'.

She mentioned that she has served as a consultant or data analyst employee of the FDA for four years and then she set up her own company previous summer to analyze FDA’s public data.