Of course, my medical mind wants even more information!
There are some cancers whose progress is monitored by hormonal assays. For example, choriocarcinoma is followed by checking levels of Human Chorionic Gonadotropin - the pregnancy hormone looked for in pregnancy tests. Another cancer marker that is followed with blood tests is Alpha Feto-Protein - and this is also a chemical that is measured in a very common genetic test during pregnancy.
For me, the icing on the cake of this story would have been if the baby's cord blood had been used to further treat mom's cancer. It has happened.