London: Rod Stewarts`s wife Penny Lancaster suspects "killer cells" may have terminated a twin to her new baby.
Model Penny, 39, said doctors believed she was expecting twins but one may have died.
"When I got the positive pregnancy test I found out the killer cells were becoming aggressive,” the Sun quoted her as saying.
"When they (the doctors) found out about the killer cells, they put me on a course of steroids which helped suppress them.
"They concluded there might have been more than one baby, but the killer cells got to one of them," she said.
Penny also revealed how she suffered a miscarriage when she and Rod first decided to have children but never thought she would have problems again after the birth of their son Alastair, now four.
"When we first decided to have children I fell pregnant and sadly had a miscarriage,” she said.
"The very next month I fell pregnant with Alastair. It was most natural process. Everything went smoothly and I had a natural birth, so there was no reason to assume we``d have difficulty conceiving again," the rock star’s wife added.
After a string of problems, she and Rod, 65, decided to go down the path of IVF.
After three cycles of treatment she fell pregnant. The baby, which is due in March, will be Rod``s eighth child.