Aspectos EpidemiológicosBackground: Assisted reproductive technologies (ART), such as in vitro fertilization, intracytoplasmic sperm injection (ICSI), assisted
fecundation, and all the fertility treatments and procedures, have been successfully used to overcome infertility. Indeed, it has been estimated
that between 1 and 4% of births in developed countries are conceived trough ART. But at the same time, rising concerns exist on
their potential adverse effects on the embryo and fetal development. However, in spite of the huge amount of studies that have been
published, big gaps in this knowledge still exist. To assess this association through epidemiological studies, it is necessary to recognize which
maternal characteristics, among others, could confound the results. However, some of the maternal characteristics may be related with cultural
and social aspects, as well as with other local influences. Therefore, it is advisable to identify those characteristics in the different populations.
Objective and methods: Here we present the results of the analysis of several maternal characteristics on data from the cases and controls
´ mothers of the ECEMC database. The analysis included 20,233 mothers of consecutive live born infants with congenital defects, and
19,411 mothers of control infants. The studied characteristics were: maternal age ( 19, 20-30, 31-35, 36), level of education (primary,
secondary, and university studies), body mass index (BMI) in three strata (30), maternal chronic diseases, maternal diabetes
mellitus, hypertension, gestational diabetes, infectious diseases during pregnancy, tobacco and alcohol consumption while pregnant, multiple
births, and caesarean section. Due to the number of analyses performed, the statistical significance was established in p<0.01.
Results: We have observed that women undergoing ART are older, with higher educational levels, suffer more chronic diseases, higher
frequency of gestational diabetes, and more infectious diseases than mothers with natural conceptions. Most of these results are observed
either in cases´ mothers or controls´ mothers, but did no differ when we analyzed cases versus controls´ mothers, all of them using ART for
conception. On the other hand, mothers following ART, are less smokers, do not have more frequency of both diabetes mellitus and hypertension.
Regarding the BMI, the only statistically significant result is an increased frequency of women having a BMI of <25 among those
following ART.
Conclusions: Many of the studied characteristics can be confounder factors for epidemiological analyses to identify potential risks of
ART to produce birth defects. In addition, although most of the results are similar to those observed in other studies, particularly in Sweden,
some of the observed differences may be due to variations in social and educational aspects. Therefore, it is advisable to identify which
maternal characteristics can be confounder factors in each population.N
