When it comes to the effects of caffeine, the research has been mixed.
While some studies have linked the caffeine with a lower risk of miscarriage and stillbirth, others have shown no significant effect.
And the evidence has been shaky.
The latest study published in The Lancet, a British medical journal, is the first to look at the effects on women who have had a miscarriage or are expecting one.
The researchers found that, if caffeine is taken within the first six hours of conception, the risk of stillbirth is reduced by as much as 30 per cent.
The authors of the study say this could be because the body absorbs caffeine as a liquid and metabolises it quickly.
But the researchers said this was not conclusive because they could not find any studies comparing caffeine levels with the amount of caffeine taken by pregnant women.
“Our results show that caffeine can reduce stillbirth risk by as little as 30% for women who are already pregnant,” said lead author Dr Caroline Deane.
Dr Deane said it was possible that the caffeine could have a positive effect on pregnancy and pregnancy outcome in women who already had the condition.
“We don’t know if it would reduce the risk significantly, but if you’re a mother and you’re already pregnant, you’re likely to have a lower chance of miscarriage,” she said.
“I think that it is a really important study.”
The research was conducted on 2,074 women who had a pregnancy loss and 2,816 who were expecting a pregnancy.
The women were recruited from a cohort of 5,092 pregnant women in the United States.
The women were asked whether they had been drinking caffeinated or non-caffeinated drinks during their pregnancy.
Dr deane said the data was not enough to make conclusions about the potential benefits of caffeine in the first three months of pregnancy.
“It’s just one study,” she explained.
“There’s no data for what the effect might be when you’re pregnant.
It’s really hard to tell whether it’s a good thing or not.”
Caffeine is widely used as an energy drink and as a sleeping aid.
The World Health Organisation (WHO) recommends that adults drink no more than one to two cups of coffee a day.
Dr Andrew Walker, of the University of Otago in New Zealand, said the results were consistent with the research.
“Caffeinated coffee is a good source of caffeine and is well tolerated by women,” he said.
The findings are consistent with what other studies have found, he added.
“You should take some coffee, even if you only have one cup.”
Dr Walker said he did not think it was a bad idea to take caffeine if it was available.
“If you can’t get it in the form of a pill or a tablet, it’s not a bad thing,” he explained.
Dr Walker also said he would recommend that pregnant women take a multivitamin and supplement in addition to caffeine.
“This could potentially be a good strategy,” he suggested.
Dr Alain Levasseur, a professor of obstetrics and gynaecology at the University Medical Center Groningen, said there was no evidence to support the benefits of taking caffeine during pregnancy.
However, he did say that the findings showed that taking caffeine could be beneficial to women.
Dr Levaseur said it might be important for women to know whether they were taking caffeine at all.
“At the moment, we don’t really know if the effects are actually the same,” he told ABC Radio New Zealand.
“But I do think that women who use caffeine at the time of conception are more likely to be able to conceive.”