Many Embryo deaths are caused because of incorrect number of chromosomes

Before even a mother realises, she is pregnant, over half of fertilised eggs experience a very early death

Very many embryos have the wrong number of chromosomes, often 45 or 47, and nearly all of these die in the womb

Even in cases like Down syndrome with three copies of chromosome 21, about 80 per cent sadly will not make it to term

If the death of an embryo would benefit the other children of that mother, as the selfish chromosomes will frequently be in the siblings

He said, “In over 2000 fish embryos not one was found with chromosomal errors from mum.”

Birds likewise have a very low rate- roughly 1/25th of what all mammals experience and the probable reason Hurst pointed is nestling competition

Humans also only have one child at a time and the death of an early embryo allows the mother to quickly begin another pregnancy