Life in the womb

Pregnancy is an intense competition between mother and baby, according to some experts.

Professor David Haig from Harvard University compared the battle between mother and child to siblings' tendency to squabble for resources and attention.

"I expect this to be happening before birth in the uterus. For foetuses to be making demands on mothers, and mothers not giving everything, in a metaphorical sense, that it wants."

But many pregnancies do fail to carry on beyond the early stages because the mother's body rejects these demands.

Child psychologist Laverne Antrobus looks at the theory of foetal maternal conflict, and speaks to the scientists and doctors who help to make sense of life in the womb.

Growing Babies is a two-part series starting Thursday 4 December on BBC4 at 21.00 (GMT).