Pregnant women with morning sickness should be offered drugs to manage their symptoms, leading doctors have said.
Women with mild nausea and vomiting should be given specific drugs used to treat their symptoms, according to new guidance published by the Royal College of Obstetricians and Gynaecologists (RCOG).
Morning sickness can affect up to four in five pregnant women and despite its nickname, it can strike at any time of day or night. For most it goes away after 14 weeks but for others it can last much longer.
The new guidance also offers insight on complimentary therapies to combat morning sickness.
The traditional remedy of ginger is recommended by the authors after they reviewed evidence which suggests it is better than a placebo to overcome nausea and vomiting.
But the experts said there is "no sufficient evidence" to recommend hypnosis to treat the condition.
Morning sickness can be particularly bad for the small proportion of pregnant women who suffer from hyperemesis gravidarum - an extreme form of the condition that struck down the Duchess of Cambridge during her pregnancies.
This severe form of the condition affects up to 3% of pregnant women. It is characterised by severe, protracted nausea and vomiting associated with weight loss of more than 5% of pre-pregnancy weight, fluid loss or dehydration.
The new guidance, which is to be published at RCOG's world congress in Birmingham, also offers tailored advice to help women with hyperemesis gravidarum.
It suggests clinicians should consider the effect on a woman's mental health during pregnancy and postnatally and refer her for psychological support if needed.
Lead author of the guideline, Dr Manjeet Shehmar, consultant obstetrician and gynaecologist, said: "Women suffering from nausea and vomiting and hyperemesis gravidarum can face a challenging time in early pregnancy. The more severe the condition, the more it can affect their day-to-day quality of life and mental health.
"Women with persistent nausea can often feel that there is a lack of understanding of their condition, they may be unable to eat healthily, have to take time off work and feel a sense of grief for loss for what they perceive to be a normal pregnancy.
"It is therefore vital that women with this condition are given the right information and support and are made aware of the therapeutic and alternative therapies available to help them cope. Women should be encouraged to rest as much as they can as this has been shown to relieve symptoms."
Professor Alan Cameron, RCOG's vice president for clinical quality, added: "This is the first edition of this guideline on this important topic, which affects many women at a crucial time in their lives.
"Women suffering severely may need input from a multi-disciplinary team including midwives, nurses, dieticians and a mental health team. This will ensure they receive the best possible care and support."
Caitlin Dean, chairwoman and trustee of the charity Pregnancy Sickness Support, said: "These long-awaited guidelines will make a huge difference to women affected by nausea and vomiting in pregnancy and hyperemesis gravidarum, not just in the UK, but on an international scale.
"A major barrier to effective care and treatment for this debilitating condition has been the simple lack of guidelines and therefore the heavy burden for clinicians to prescribe off-licence for a condition which many GPs and smaller hospitals rarely see.
"These guidelines will give clinicians the confidence to treat the condition in the evidence-based, stepwise approach which we have been advocating for a number of years. It will also give women affected the empowerment and confidence so desperately needed to maintain their pregnancies as safely and comfortably as possible."
Louise Silverton, director for midwifery at the Royal College of Midwives, said: "This is an important guideline that acknowledges how disruptive nausea and vomiting can be for women during pregnancy, as well as providing treatment options.
"In addition it covers guidance for care for women with excess vomiting that requires admission to hospital for the management of dehydration and under-nutrition.
"Much nausea and vomiting is in early pregnancy, sometimes before women have entered the maternity care services. Where women have received midwifery care, it is important that women know how to contact services when vomiting becomes persistent or debilitating."