Around 80 percent of mothers-to-be get some form of the illness – with two percent diagnosed with its most extreme form hyperemesis gravidarum, from which the Duchess of Cambridge suffered. Picture: AP

London - Millions of pregnant women are to get relief from morning sickness after the first drug to treat the condition in three decades was granted a licence.

Health regulators have ruled nausea pill Xonvea safe to use.

In clinical trials the drug was found to reduce the amount of nausea by two-thirds and cut the number of episodes of sickness from four a day to one.

For years doctors have been reluctant to prescribe anti-nausea drugs in pregnancy for fear of complications following the 1960s scandal over thalidomide, the drug which led to birth defects in an estimated 10 000 babies. 

The lack of a licensed treatment has left 690 000 women a year to suffer morning sickness, with many relying on traditional remedies such as acupuncture and ginger.

Around 80 percent of mothers-to-be get some form of the illness – with two percent diagnosed with its most extreme form hyperemesis gravidarum, from which the Duchess of Cambridge suffered.

The latter’s crippling effects have been likened to the nausea caused by chemotherapy and can cause pregnancy to be so unbearable that experts say it leads to hundreds of abortions a year.

Xonvea – which combines antihistamines with vitamin B6 in a pill taken up to four times a day – has been available in Canada since 1979 and the US since 2013.