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Date of issue: April 2020, Version: 3

An Expert Working Group (EWG) of the UK’s Commission on Human Medicines (CHM) has published their report on the use of hormone pregnancy tests (HPTs) and adverse effects relating to pregnancy including possible birth defects. Please click here for further information.

Primodos (10mg norethisterone acetate + 0.02mg ethinyloestradiol) was used as an oral hormonal pregnancy test from 1953 to 1975. Concern was raised in the mid-1960’s regarding a possible increase in congenital malformations in infants exposed in utero to Primodos and other oral hormonal pregnancy tests. As a consequence of the introduction of urine-based pregnancy tests and the withdrawal of Primodos from the market, pregnancy safety data are limited.

Although some studies have suggested a possible association between Primodos exposure and increased rates of specific congenital malformations, the more methodologically robust prospective controlled studies have not provided evidence of such. Similarly, the methodologically limited data relating to oral hormonal pregnancy tests as a group do not conclusively provide evidence of an increased risk of malformation or specific pattern of malformation in exposed fetuses.

Referral to a clinical geneticist is recommended in all cases where a causal association between a congenital malformation and in utero exposure to an oral hormonal pregnancy test is being questioned, as identification of an underlying genetic cause may have implications in terms of recurrence risk for the individual and other members of the family.

This is a summary of the full UKTIS monograph for health care professionals and should not be used in isolation. The full UKTIS monograph and access to any hyperlinked related documents is available to NHS health care professionals who are logged in.

If you have a patient with exposure to a drug or chemical and require assistance in making a patient-specific risk assessment, please telephone UKTIS on 0344 892 0909 to discuss the case with a teratology specialist.

If you would like to report a pregnancy to UKTIS please click here to download our pregnancy reporting form. Please encourage all women to complete an online reporting form.

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