The discovery of a foreign body in the womb of a pregnant Tauranga woman had doctors wondering what the 24mm long, white object was.

Emma and her partner had been trying for a baby for eight years, and news of the foreign object turned an exciting time into a 'horrible pregnancy”.

Maia is a miracle baby for her parents. Photo: Ross Brown/Fairfax NZ

Emma says she was worried the whole time that she would lose her baby.

An ultrasound at six weeks revealed a healthy foetus but also in Emma's womb was what doctor's thought at the time was a piece of metal or dense plastic.

An operation to remove the object was deemed necessary, but came with a 50 per cent chance of a miscarriage.

Maia survived the operation but the object could not be removed.

Specialists assumed the object was either an intra-uterine device – even though Emma said she'd never had one – or a medical tool left inside her after fertility tests, reports Fairfax.

The only other surgery Emma had was an abortion in 1998.

All doctors could do was monitor her progress, and hope that whatever it was did not get too close to the baby.

'They pretty much said I would be really lucky if I could keep the baby,” says Emma. 'I was just told to hope for the best. It was horrible - a horrible pregnancy.

'I had to go to the hospital every month. It felt like the doctors were just hoping it wasn't something that could be pinned on them.

'I never got a sorry. Just... hope for the best. But what can you do? There was nothing anyone could do.”

Emma gave birth to Maia six months ago and despite being four weeks early, the baby girl was healthy.

The object also dislodged during the birth and was sent away for testing. It was later revealed to be a calcified bone fragment of either a foetal femur or thigh bone.

The size of the bone matched the gestation of the pregnancy Emma terminated when she was 15, almost 17 years ago.

One in 1000 women who have terminated a pregnancy are found to be infertile with calcified remnants.