Does an unborn baby's blood get mixed with his mothers?

The biggest surprise during my 40 years working in a clinical laboratory was that the placenta, once called the barrier between mother and baby is more like a porous sieve, allowing some exchange of cells between mother and baby. HERESY ! read more

During birth, a baby’s blood can and does mix with his mother’s blood. For mothers who are Rh -ve, and are giving birth to a baby who is Rh +ve, this used to cause problems in subsequent pregnancies of Rh +ve babies. Nowadays, the baby’s blood group is tested after birth to see if the baby is Rh+ve. read more