The end of morning sickness? Scientists finally discover cause of common pregnancy woe in massive breakthrough
A safe drug taken before women become pregnant to prevent morning sickness could be on the horizon following a major scientific breakthrough.
Up to 70 percent of pregnant women experience nausea and vomiting.
Scientists previously found a hormone that appeared to trigger morning sickness in the brain, but have spent nearly a decade trying to understand how it works.
Their breakthrough is the new discovery that this hormone, called GDF15, must be present at high levels in a pregnant woman's body, but she must also have had low levels of it before pregnancy in order to suffer from morning sickness.
A sudden increase in the hormone, higher than what a woman had previously experienced, appears to cause the nausea and vomiting.
The condition is perhaps best known for affecting Catherine (above in April 2013), Princess of Wales, who was hospitalized for several days in 2013 while pregnant with her first child, Prince George.
This discovery paves the way for a drug that women can take before they even become pregnant to replenish their GDF15 so they are much less likely to experience morning sickness.
Metformin, currently given to people with type 2 diabetes, is a promising candidate, and researchers are preparing to test it in women as soon as next year.
Such a pre-pregnancy drug would be a lifeline for women; many of them suffer from morning sickness and are afraid to take anti-nausea medications during pregnancy, despite evidence for their safety.
It could also provide much-needed hope for hyperemesis gravidarum, a debilitating form of illness during pregnancy that is much more serious than morning sickness and affects up to three percent of pregnancies.
This life-threatening condition, made famous by the Princess of Wales, Kate Middleton, can cause illness dozens of times a day, with some women eventually being hospitalized with severe dehydration.
Professor Sir Stephen O'Rahilly, from the University of Cambridge, led a study presenting the new findings and said: 'Severe nausea and vomiting during pregnancy is common and very disabling for women.
'Our findings convincingly demonstrate the role of the hormone GDF15, and should change the way we treat morning sickness, or hyperemesis gravidarum, to reduce women's suffering.'
Women have low levels of the hormone GDF15 in their bodies before they become pregnant, but this is replenished during pregnancy.
Researchers now also know that it is pregnancy itself that increases the hormone, because GDF15 is produced while the placenta is being formed.
The scientists had early evidence that GDF15 tended to be higher in women with gestational illness, and confirmed this in the new study using high-quality blood tests in more than 400 women.
But this was clearly not the full story, as women with very high GDF15 did not always have morning sickness or hyperemesis gravidarum (HG).
To understand how the hormone worked better, researchers looked at women with a rare genetic mutation known to increase the risk of HG during pregnancy tenfold.
They discovered for the first time that these women had very low levels of the hormone GDF15 before pregnancy.
The missing piece of the puzzle, which suggests that women need both a low GDF15 before pregnancy and a high GDF15 during pregnancy to get sick, was confirmed using a questionnaire given to twenty new mothers with the blood disease thalassemia major.
These women, who never had low GDF15 levels before pregnancy due to their condition, also reported hardly any morning sickness compared to other women.
Another study in mice found that those given a sudden injection of GDF15, as women experience during pregnancy, only seemed to feel ill and reduce their food intake if they started with low levels of GDF15.
The detailed study, conducted by an international team of scientists and published in the journal Nature, suggests that building a woman's tolerance to the hormone before pregnancy, by giving her a drug containing it, could be key to prevent morning sickness.
The researchers say their data suggests that a drug that doubles GDF15 levels before pregnancy could halve the risk of someone developing HG.
Metformin will likely be tried first in women who have previously had HG and hope to avoid it in future pregnancies.
Preventing the hormone from causing nausea, by using an injection to block the nausea, could be another possible treatment approach, although this should be safe for pregnant women.
It is likely that morning sickness was necessary in hunter-gatherer times, to keep women away from foods that could be poisonous to her baby, but it no longer serves a function.
The extreme morning sickness almost ended my pregnancy
Vomiting as often as 30 times a day became the new normal for Charlotte Howden during her pregnancy in 2016.
But initially she was only given the usual advice for morning sickness, such as eating little and often and trying ginger.
It wasn't until she was three months pregnant that she realized from reading her hospital notes that she had hyperemesis gravidarum, which is a very different condition from morning sickness and can be life-threatening for mother and baby.
Mrs Howden, 40, said: 'A lot of people, from early health professionals to even friends and family, would think I just had morning sickness and should be able to pull myself together and deal with it.
'You feel so isolated and broken, dealing with such extreme illnesses during your pregnancy, which is so different from what most other people experience.'
The mother-of-one, who lives with her husband William and seven-year-old son Henry in the Hampshire village of Curdridge, started feeling sick around week six of her pregnancy.
Vomiting as many as 30 times a day became the new norm for Charlotte Howden during her pregnancy in 2016. But initially she was only given the usual advice for morning sickness, such as eating little and often and trying ginger. Pictured with her seven-year-old son Henry
But within less than a week, she was getting sick dozens of times a day and couldn't keep food down.
Even a sip of water or swallowing her own saliva can trigger a vomiting fit.
It took weeks before she was put on medication that allowed her to sleep 20 hours a day, but that didn't prevent her from being hospitalized every few weeks with severe dehydration from the vomiting.
Mrs Howden, now director of the charity Pregnancy Sickness Support, said: 'I begged the consultant to help me as I was about to make the decision to terminate my pregnancy.
'It wasn't until week 16 of pregnancy that I got the right treatment.'
The campaigner is desperately grateful for the scientific breakthrough that is raising hopes for a future treatment for HG.
She said: 'When you're suffering from a condition and no one can tell you why, you start to think: is it me? Is it something I did?
'I hope this will pave the way for a treatment that will greatly reduce the risk of developing HG, and in the meantime the publicity will encourage doctors to recognize this condition and get women the care they need.'