The Impact of Oocyte Vitrification on Offspring: a Systematic Review

Oocyte vitrification is a widespread and well-established assisted reproduction technique that has enabled some patient groups to obtain clinical results equivalent to those using fresh oocytes. However, as the number of babies born from vitrified oocytes has increased, so has the discussion regarding the method's safety for the offspring. Cryogenic oocyte damage caused by chemical, mechanical, and thermal stress has raised concern. In this systematic review, we asked the question of whether oocyte vitrification impacts offspring health. From 2007 to 2021, 13 studies were included in the analysis. All studies were observational and presented neonatal outcomes. A total of 4,159 babies were analyzed. Data from these studies were used to assess the following outcomes: multiple pregnancies, cesarean section, gestational age at delivery, the number of live births, birth weight, Apgar scores, congenital anomalies, and baby health. The most extended follow-ups evaluated children until 1, 2, and 6 years of age. According to the evidence appraised in this systematic review, vitrification seems to be a safe method for oocyte cryopreservation and child health, at least in the short term. Nevertheless, there is an urgent need for additional long-term data results from big databases and also for randomized controlled trials to improve the levels of evidence.