An Israeli study has found that Yom Kippur is boom time for maternity wards - and that the reason may not be positive.

Obstetrician and gynaecologist Eyal Sheiner has concluded that Jewish women are much more likely to enter premature labour on the Day of Atonement than during the rest of the year.

The reason, he believes, is because many of them are fasting, and the lack of food and drink triggers early labour.

He has concluded that Yom Kippur is an "independent risk factor for pre-term deliveries," and says that he views this with concern because of the dangers associated with early delivery.

In preparing his study, which has been just published in the Journal of Maternal-Fetal & Neonatal Medicine, he examined records of Yom Kippur deliveries over 23 years at Soroka Medical Centre in Beersheba, where he works. Most patients in its busy labour wards are Bedouins or Jews, and he found that, while Bedouins are no more likely to go into labour on Yom Kippur, Jews are twice as likely.

Dr Sheiner says that this is unsurprising, given that early contractions are often associated with dehydration.

"Whenever a patient comes to you with contractions, the first thing you do is to given them fluids," he said.

He was prompted to undertake the study because he had a hunch that there was extra demand for delivery rooms during the fast.

"We have always had the feeling that Yom Kippur is a day of many deliveries, and we wanted to look in to this," he said.

Dr Sheiner said that, while he was reluctant to set medical guidelines: "I'm recommending that my patients do not to fast during
pregnancy."