Stephanie Seneff, Ph.D., sent me a 2006 study6 that could explain this, as it showed sperm can take up foreign mRNA, convert it into DNA, and release it as little pellets (plasmids) in the medium around the fertilized egg. The embryo then takes up these plasmids and carries them (sustains and clones them into many of the daughter cells) throughout its life, even passing them on to future generations.
It is possible that the pseudo-exosomes that are the mRNA contents would be perfect for supplying the sperm with mRNA for the spike protein. So, potentially, a vaccinated woman who gets pregnant with an embryo that can (via the sperms’ plasmids) synthesize the spike protein according to the instructions in the vaccine, would have an immune capacity to attack that embryo because of the “foreign” protein it displays on its cells. This then would cause a miscarriage.