From morning sickness to swollen ankles and high blood pressure, pregnancy certainly takes its toll on a woman's health.
But the damage may run deeper than she realises.
Scientists say that cells pass from baby to mother during pregnancy - and can linger in the woman's body for decades.
Some of them may be good for her health but others, depending on where they hide in her body, could raise her risk of a host of illness. Breast cancer, thyroid cancer, arthritis and early menopause could all be triggered or exacerbated by these 'alien' cells, experts say.
Incredibly, they believe some of the cells may be effectively trying to sabotage the mother's chances of having another baby so the foetus will not have to compete for resources after it is born.