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Antioxidants may stop
miscarriages
Oxygen may be essential for life but a sudden rush during
the early weeks of pregnancy could spell death for a foetus, British scientists said.
Their study found that the amount of oxygen foetuses receive tripled between the eighth
and 15th week of pregnancy, and that this could account for a significant number of
miscarriages.
One in six pregnancies ends prematurely, and
obstetricians called for more tests to see whether high doses of antioxidants could help
cut the risk of miscarriage. 'People have known for a number of years that this period of
pregnancy is a vulnerable one and I think we are finally able to give a clue as to why
that is the case,' Graham Burton, of Cambridge University, told.
Burton and his colleague Eric Jauniaux, of University
College London, placed a tiny monitor in the placentas of 30 women and studied the oxygen
levels during their first three months of pregnancy. Most embryologists have traditionally
thought that oxygen levels gradually increase during pregnancy.
But Burton and Jauniaux's research found that oxygen
levels in the blood flowing through the umbilical cord tripled between the eighth and 15th
week of pregnancy. 'There is in fact very little blood flow to the placenta before about
10 weeks of pregnancy, and in cases which are about to miscarry then there is an excessive
and early onset of maternal blood flow,' Burton said.
'We know that these tissues are very susceptible to
oxygen and the high levels of oxygen associated with that blood flow cause the tissues to
degenerate and hence to miscarry. 'There's a wide spectrum of conditions associated with
miscarriage, and I wouldn't say necessarily this causes all, but I think it may be
associated with a significant number.'
The research suggested that cells called
cytotrophoblasts, which anchor the placenta in the womb and invade the blood vessels to
limit oxygen intake, dissipate at about eight to 10 weeks, allowing more of the gas in. A
diet rich in antioxidant vitamins such as vitamins C and E could help protect the foetus
from this sudden change in their environment, Burton said.
'You can imagine that any additional stresses such as
alcohol or cigarette smoking which are associated with miscarriage might exacerbate that
stress, and we may be able to tilt the balance backwards by giving antioxidants which are
part of a normal healthy diet anyway.' |
