Jane Bartlett 

Sick, and tired of it

New research suggests morning sickness is a natural mechanism designed to protect unborn babies from food poisoning. So should pregnant women just heave heroically, refusing any kind of treatment? Jane Bartlett investigates
  
  


At last I have discovered why long periods of my life were spent vomiting my guts up. It was good for me. According to new research by two evolutionary biologists at Cornell University in New York, I can blame the horrendous morning sickness I endured during the first 16 weeks of my three pregnancies on my ancestors. Those women who roamed the plains and forests of our early world perfected the art of heaving up the contents of their stomachs during the first trimester because it gave them and their growing babies a better chance of survival.

According to Professor Paul Sherman and Samuel Flaxman, morning sickness, or nausea and vomiting of pregnancy (NVP), as it is medically known, protects the expectant mother from harmful organisms in food, reducing the likelihood of miscarriage by half. They looked at pregnancies documented in 56 studies from 16 different countries and discovered that approximately 10% of women who did not feel sick in pregnancy lost their babies, compared to only 4% of women who did feel sick.

The connection between pregnancy sickness and a small reduced risk of miscarriage is nothing new: I used to try and remind myself about it to maintain my spirits while bringing up my breakfast, and often lunch and supper too (morning sickness is a misnomer - it can strike any time ).

What is new is the evidence suggesting that the condition, which affects 50-80% of mothers-to-be, may be a protective mechanism against food poisoning at a time when a woman's immune system is compromised. In the latest issue of the Quarterly Review of Biology, Sherman writes: "Our study is the first to gather compelling evidence that morning sickness is nature's way of protecting mothers and foetuses from food-borne illnesses and of shielding the baby from chemicals that can deform foetal organs at the most critical time in development."

Controversially, he goes on to suggest that alleviating the symptoms through the use of drugs or natural remedies may do more harm than good "if doing so interferes with the expulsion and subsequent avoidance of dangerous food."

This recommendation will throw expectant mothers into a great quandary. Should they bin the ginger tea and acupressure wristbands (the only non-drug treatments that have been verified scientifically) and heave on heroically?

"I don't think there's any scientific evidence for that at all," says Dr Roger Gadsby, a Nuneaton GP, and one of the few medical experts in this country to have studied NVP. "If you're getting on to an evolutionary angle, there's no evidence that any other species gets it."

He also disputes the evolutionists' claims that the most common food aversions are meat, fish, poultry and eggs, because these are the ones most likely to carry harmful micro-organisms. "There haven't been enough studies to claim that these are the most common aversions," he says.

Indeed, I found that garlic, wine and tea lost their appeal entirely. Nicky Wesson, author of a book about NVP, discovered in her research the existence of 193 food aversions, with tea, tobacco, coffee, marmalade and sweet foods topping the list. "They are trying to make sense of medical facts. It is speculative. There's no hard evidence for it and there's no way they can prove what they are saying," says Jim Robins, a consultant obstetrician at Inverclyde Royal Hospital in Greenock.

Even if NVP is an evolutionary protective invention, nature can sometimes get it wrong. Before the development of the intravenous drip, NVP was a significant cause of maternal fatality, with women dying of dehydration as late as 1939. It might have guarded our guts from that suspect leg of mutton or fly-infested pig entrails, only to sweep us away later due not not being able to keep down water. Life for today's hunter-gatherers is different: NVP causes 8.5m working days to be lost annually. "This is what the people from Cornell don't explain. If their theory is right, those who got severe morning sickness were putting their lives at risk," says Robins.

However, it is laudable that NVP is being researched at all because despite being so common, the causes are still contested. Low blood sugar levels, high levels of the hormones oestrogen and human chorionic gonadotrophin, which are released by the placenta in early pregnancy, are popular theories. Or it could be an immunological response to the "foreign body" that is the foetus growing inside the womb.

Why some women get it so badly that they have to be admitted to hospital or have a therapeutic abortion, and others have no nausea at all, is a mystery. However, recent research in Sweden shows that women who suffer from very severe NVP are statistically slightly more likely to be carrying a girl (a ratio of 44.3 boys to 55.7 girls, only just better as a predictor of sex than flipping a coin).

Gadsby's response to the evolution theory is: "So what? It has no meaning or consequence."

The findings certainly have little relevance in a society in which refrigeration is usual and food handling procedures are dictated by law. Gadsby does suggest that women continue to find ways to relieve their discomfort, and recommends regular snacking as the best control for nausea.

Help yourself

* Have small regular snacks, every two hours. Go for high carbohydrate plain foods, like crackers and bread.

* Don't let yourself get hungry.

* Rest as much as possible. Tiredness make sickness worse.

* Sea-Bands wristbands stimulate an acupuncture point in the wrist, which many find alleviates nausea. Some studies have shown them to be effective. Available at most chemists.

* Grate fresh ginger into a cup. Pour hot water on top, leave for a few minutes then drink. Ginger biscuits and ginger beer may also help.

* Homopathic treatment may help but there are different remedies depending on the individual. It's best to consult a qualified homopath. If treating yourself, ipecac is the standard remedy.

* Nicky Wesson, author of a book on NVP, recommends taking zinc supplements, quoting a study that found 42% of pregnant women were eating less than the recommended daily intake.

 

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