Full moon and thunderstorms - what made Kate Middleton go into labour?

It's hardly a surprise that the Duchess of Cambridge has gone into labour with the royal baby - the reported due date was over a week ago and first babies are notorious for arriving a little late.

But some midwives and baby experts reckon there's more to the royal baby's arrival than simple dates, instead suggesting the full moon and even an isolated thunderstorm in London helped encourage the the tot to begin its journey into the world.

Anecdotally, midwives say that more babies are born at the full moon stage of the lunar calendar than any other time of the month. A (sort of) scientific explanation for this is that the gravitational pull affects the amniotic fluid that the baby is encompassed in in its mum's tummy, in the same way it affects the water in the sea and rivers - causing tides.

Mervi Jokinen, of the Royal College of Midwives, said midwives often talk of how the full moon makes for a busy spate of deliveries.

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"It's always sort of been an old wives tale saying that the full moon brings women into labour. Midwives usually do say 'I'm on call. It's a full moon. I'll be busy tonight'," she said.

"There was a study about 20 years ago at a hospital near the River Thames which is a tidal river and it showed that on the full moon they did have more births.

"The idea is that because the baby is surrounded by water, the time of the full moon and the high tide causes the waters to break.

"But there's not enough scientific evidence to show it's proven."

Birth doula Zara de Candole, of Doula UK, said: "As a doula (birth coach) who has supported many women in labour, there does seem to be some link between labour kick starting and a full moon."

There are also suggestions electrical storms and a drop in barometric pressure can bring on labour.

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Western central London - near where William and Kate's Kensington Palace apartment is based - experienced isolated heavy rain, thunder and lightning strikes at 6am this morning - just at Kate was admitted to the Lindo wing of St Mary's Hospital in Paddington. Quite a coincidence, don't you think?

Chris Burton, a forecaster with MeteoGroup, the weather division of the Press Association, said: "The storm affected western central London. There were lightning strikes at around 6am and very localised, intense heavy rain and thunder.

"We've had high pressure with the sunshine but now there's low pressure and it's hot and humid which can cause thunder storms."

Mervi Jokinen said she had not seen a connection between labour and electrical storms.

"We are full of electrolytes but I don't know. it's not something we've discussed as a midwific community. I can't vouch for that," she said.

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She added that babies also arrived to their own agenda and their own time scale and put in an appearance when they are ready.

"Nature has its own way of preparing for labour. Before the baby comes, the body needs to do some preparations and that's very important," she said.

Speaking of star signs, the baby's imminent arrival is on the cusp between two - Cancer and Leo - and depending on how long labour takes, could be either.

Often babies born on the cusp show signs of both stars - if, of course, you believe in horoscopes. Diana, the baby's grandma, was cancerian, as is dad Prince William. The Duchess is Capricorn.

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