Consumo de Antihistamínicos-H1 durante el primer trimestre del embarazo en España, y estimación del riesgo global para defectos congénitos en el recién nacido / Consumption of H1 antihistamines during the first trimester of pregnancy in Spain, and estimation of the overall risk for congenital defects in the newborn

Resumen

H₁ antihistamines (H1A) are drugs that have been used for many years for treatment of allergic diseases, as for the control of nausea and morning sickness in pregnant women. Here it is analyzed the evolution of their global use during gestation and by the different groups of H1A, along the last 31 years in the ECEMC data. In addition, their potential risk on the embryo development regarding congenital defects is analysed. The data belongs to the Spanish Collaborative Study of Congenital Malformations (ECEMC), for the period 1977-2008. The ECEMC is a hospital-based, case-control study and surveillance system, aimed at performing clinical and epidemiological studies on congenital defects, the methodology of which includes the collection of about 310 items on each newborn infant registered, whether case or control, on their pregnancy and family history, and many types of prenatal exposures. During the study period the ECEMC surveyed and examined a total of 2,607,822 consecutive newborns, and a total of 39,561 out of them had congenital defects identifiable during the first three days of life. After having excluded those cases diagnosed centrally at ECEMC as presenting with syndromes, the studied samples were 33,056 cases and 32,258 controls. The total data of the different tables may not be the same because they include only the cases and controls with each data specified. The analysis of the evolution of H₁A consumption by pregnant women in Spain along the years showed a statistically significant increasing trend, from 12.66% and 11.51% for cases and controls, respectively, in 1977 to 13.90% and 15.86%, respectively, in 2008. This increase has occurred at the expense of doxilamine (combined with vitamin B6) used as an antiemetic, and of three subgroups of H1A used in the control of allergic processes (Alquilamines, Piperazines, and Piperidines). None of the subgroups of H1A has shown an increased risk for birth defects (after its use during the first trimester of pregnancy), except the group of Piperidines (OR=6.83; p=0.003). However, due to the small samples of exposed infants, it is not possible to perform any type of multivariate analysis to control for possible confounders. Hence, we cannot rule out that the observed risk could be due to uncontrolled factors. If a pregnant woman had allergic problems and needs to be treated, she has to be treated because the risks for her and for the embryo overwhelm the ones derived from the treatment if any. For such treatment, if the allergic process only can be controlled with a piperidine, this product could be used, although not as the first option. On the other hand, the combination of doxilamine and pyridoxine (vitamin B6) is a safe option for the control of nausea and vomiting during pregnancy.