Eating pâté and soft cheese is ‘MORE dangerous in pregnancy than experts once thought – causing early miscarriage’
BACTERIA found in pâté, soft cheese and cold meats is a greater risk to your unborn baby than experts once feared.
Listeria can cause miscarriage in the early stages of pregnancy, new findings have revealed.
Mums to be in the UK are warned by the NHS to avoid the bug, which can cause listeriosis - a nasty infection linked to meningitis, severe headaches and tremors.
The bacteria is typically found in chilled "ready-to-eat" foods, including pâté, soft cheeses including Brie or Camembert, soft blue cheese and goat's cheeses, as well as cooked sliced meats and smoked salmon.
Scientists have known the bacteria is a particular threat in the later stages of pregnancy.
But, now a team at the University of Wisconsin-Madison, have warned the bacteria poses a "severe risk in early pregnancy".
Prof Ted Golos, who oversaw the study, said: "For many years, listeria has been associated with adverse outcomes in pregnancy, but particularly at the end of pregnancy.
"What wasn't known with much clarity before this study is that it appears it's a severe risk factor in early pregnancy."
Pregnant women are almost 20 times more likely to develop listeriosis compared with the rest of the population.
What wasn’t known with much clarity before this study is that it (listeria) appears it’s a severe risk factor in early pregnancy
Prof Ted Golos
They are at heightened risk because the body's natural defences against the bug are weaker while they are expecting.
While the infection is likely to be mild in mum, it can cause miscarriage, still birth and premature labour.
One of the dangers of the bug, is there are few symptoms - and those pregnant mums suffer are easily mistaken for the earliest signs of pregnancy.
Prof Golos said: "It's striking that mum doesn't get particularly ill from listeria infection, but it has a profound impact on the foetus.
"That's familiar now, because we've been talking about the same difference in Zika virus."
Researchers fed doses of listeria - similar to the amount found in food - to four pregnant monkeys.
Graduate student Bryce Wolfe, then monitored the speed and progression of the bug's spread.
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This allowed scientists to see how the bug was shed in faeces and showed up in the bloodstream.
Ultrasound scans then showed how the bacteria can spread to the foetus.
None of the monkeys showed obvious signs of listerosis infection before their pregnancies suddenly came to an end.
But tests showed the listeria had invaded the placenta - the connection between mum and baby that is designed to protect the foetus and prevent bacteria crossing to the baby.
The bug was also found in the lining of the womb.
Wolfe said: "In that region, there's a rich population of specialised immune cells, and it's exquisitely regulated.
"When you introduce that pathogen into the midst of this, it's not very surprising that it's going to cause some sort of adverse outcome disrupting this balance."
Prof Golos's team also think inflammation caused by the mum's immune system also affects the placenta, stopping it from protecting the baby.
"It should be a barrier," he said.
"But we're hypothesising that the maternal immune system's attempt to clear the bacteria actually results in collateral damage to the placenta that then allows the bacteria to invade the foetus."
WHAT FOODS SHOULD MUMS TO BE AVOID?
THERE are certain foods mums to be are advised to avoid in pregnancy, because they risk making you ill or harm your unborn baby.
Cheeses to avoid
Soft cheeses with a rind, such as brie and camembert, as well as goats' cheese are only safe to eat if they have been cooked.
Pregnant women should also avoid soft blue cheeses, such as Danish blue, gorgonzola and roquefort - again unless they have been cooked.
Other foods to avoid
- pate, including veggie pates
- raw or partially cooked eggs
- raw or undercooked meat
- cold cured meats
- liver
- game
Fish to avoid
- shark
- swordfish
- marlin
Fish to restrict
- no more than two tuna steaks a week
- no more than four medium-sized cans of tuna
Shellfish
Always eat cooked rather than raw shellfish, including mussels, crab, lobster, prawns, scallops and clams
Milk and yoghurt
Stick to pasturised or ultra-heat treated milk, also known as long-life milk.
Don't drink or eat foods made from unpasturised goats' or sheep's milk
Caffeine
High levels of caffeine can result in babies having a low birth weight, or increase the risk of miscarriage.
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The findings, published in the journal mBio, suggest this bacteria and others, could be responsible for miscarriages that are thought to be a mystery.
Prof Golos said despite knowing this, listeria's stealth and speed may still make it hard to control.
"There are effective antibiotics available. It is treatable," Wolfe said.
"The issue is that because it's asymptomatic, the foetus may be infected by the time anyone realises the mother was infected."
The team are planning further research to look at how the bacteria targets the reproductive tract, its incubation time - how long it survives in the body - and the problems that trigger miscarriage.
Their findings could also shed light on how the Zika virus infects unborn babies.
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