80. Dental amalgams and risk of gestational hypertension in the MIREC study (lay summary)

Camara LR, Trottier H, Arbuckle TE, Fraser WD. Pregnancy Hypertension. 2020 Apr 28;21:84-89. doi: 10.1016/j.preghy.2020.04.015

Dental amalgam is a mercury and metal alloy mixture used by dentists to fill cavities caused by tooth decay.  Amalgam has been used for more than 150 years; however, there has been a significant decline in its use over the past couple of decades.  Several studies have reported associations between higher exposure to mercury and increased blood pressure; however, there have been few studies examining blood pressure and number of dental amalgams in a person’s mouth, especially for pregnant women.

The goal of this study was to test whether there was an association between the presence or replacement of dental amalgams and high blood pressure during pregnancy.

In the MIREC study, women were asked how many dental amalgams (mercury fillings) they had and whether any had been recently replaced.  Blood pressure was measured during each trimester in the 1817 pregnant women and mercury levels in maternal blood were measured in the 1st and 3rd trimesters.

Approximately 85% of the women were categorized as having normal blood pressure and 187 (9.8%) as having gestational hypertension.  Levels of mercury in maternal blood increased slightly with the number of dental amalgams in their mouth.  However, no significant association was observed between dental amalgams and risk of having gestational hypertension.

In conclusion, although women with dental amalgams in this study had slightly higher mercury levels in their blood, this was not associated with risk of high blood pressure during pregnancy.

This study was led by a graduate student at the University of Montreal.