A natural ‘shield’ that nature has created to protect women’s wellbeing. This is the feminine fertility curve, that follows a ‘U’ trend and undergoes over the years to preserve the woman both at a very young age and in old age, from the risks that pregnancy can create. An extraordinary ’security system’ that favors gestation when there are less probabilities of problems and when you are more ready to face expectation, breastfeeding and maternity as a whole. All this was highlighted in a multicenter study published in ‘Science’ journal by GeneraLife team and an international group led by Eva Hoffman of the University of Copenhagen.

The paper “Chromosome errors in human eggs shape natural fertility over reproductive life span” shows that fertility in women follows a U curve, with low fertility rates in teenagers and women of advanced maternal age. This is the result of chromosomal errors in the oocytes, which result in genomic instability and the inability to establish a pregnancy. The error types and chromosomes affected in the young and advanced age groups were different, suggesting that two distinct chromosome-based mechanisms balance risk associated with pregnancy and evolutionary fitness as women enter and exit their reproductive life span. The authors show that chromosome structure erodes only with advancing age, acting as a ”molecular clock” for reproductive senescence.

Today the most important complications in ART cycles are ovarian hyper-stimulation syndrome, which is a consequence of the necessary hormonal stimulation, and twin pregnancy. In the first case, now thanks to innovative therapeutic protocols, it is possible to bring the risk to virtually zero, but this presupposes a specific know-how. In the case of twin pregnancies, IVF centers must try to bring this risk to the physiological levels (1 event every 100 births), always trying to transfer a single embryo, identifying the one that has the greatest potential to give rise to a pregnancy.

Link: https://doi.org/10.1126/science.aav7321