What are the biggest barriers to artificial wombs?

Probably the least understood stage of pregnancy – and one of the most delicate – is around 10 days after fertilisation, when the developing egg implants into the uterus and starts to grow. Researchers are now experimenting with maintaining uterus cells outside of the body, which in future could be supported in an artificial womb and provide a place for the embryo to implant. This uterus tissue would need to have its own blood supply – something that’s not yet been achieved. Scientists believe that tackling this issue would be a major step towards artificial wombs.