The low birth weights of newborns conceived using assisted reproduction technology.

Couples are increasingly using assisted reproduction technology (ART) to facilitate having children. This raises the question of whether using ART leads to the same health outcomes as spontaneous conception.One of the major health outcome factors concerns the weight of the newborn. Many foreign studies have proved that newborns conceived via ART evince lower birth weights than newborns that were conceived spontaneously. The purpose of this study is to determine whether the risk of low birth weight differs according to the ART method selected (in-vitro fertilisation with fresh embryo transfer, frozen embryo transfer, oocyte receipt), and which of these methods is associated with the lowest risk of a low birth weight. Anonymised individual data on all deliveries that took place in Czechia between 2013 and 2018 was used for the analysis. The dataset was obtained from the National Registry of Reproduction Health (administered by IHIS CR).The binary logistic regression revealed that concerning many of the covariates controlled, women who underwent IVF had a higher risk (30 %) of giving birth to a child with a low birth weight than women who received frozen embryo transfer treatment (CI 1.15-1.48). Women who underwent oocyte receipt treatment were found to have an even higher (52 %, CI 1.17-1.97) risk than women who received frozen embryo transfer. This study supports existing international knowledge of the specifics of the health outcomes of women who use ART (Tab. 1, Fig. 3, Ref. 32). Keywords: Low birth weight, assisted reproduction technology, in-vitro fertilisation, frozen embryo transfer, oocyte receipt.