Birth Defects26 July 2013 |
Birth defects are common. They affect one in 33 babies born in the United States, according to the US Centers for Disease Control, and are responsible for 20 percent of infant deaths there.
In China, the proportion of children with birth defects has risen rapidly in recent years and is now among the highest in the world. Officials there have linked the trend to environmental pollution (see BBC reports here and here).
Common birth defects include heart disorders and “neural tube defects” which affect either the spinal column or brain. Cleft lip and cleft palate (the roof of the mouth) are also relatively common, as is a disorder called hypospadias in which the exit hole for urine is on the underside of a boy’s penis, rather than at the tip.
While some birth defects can be detected before a child is born, others – such as heart conditions – might not be obvious for years.
Many birth defects are entirely natural. They can arise through genetic mutations or because of inbreeding within closely related populations.
Birth defects can also occur because of exposure to various chemicals (such as dioxins, pesticides, phthalates, bisphenol A), and other environmental factors such as radiation, infections, and nutrient deficiencies.
It is very hard to pinpoint the cause of birth defects unless a very large number occur. The biggest example of this happening was in the late 1950s and early 1960s. More than 10,000 babies with severe birth defects were born to women who took the drug thalidomide to ease the symptoms of morning sickness while pregnant.
Large numbers of birth defects have also occurred following the US-Vietnam War (see case study) and the Second Gulf War (see Warfare) and have been directly linked to military action.
Pregnant women who consume recreational drugs, alcohol and cigarettes may also increase the chances of their baby being born with a birth defect.
It is likely that many birth defects are the result of a mix of genetic, environmental and behavioural factors.
Women can take steps to reduce the chances of having a baby with a birth defect by avoiding exposure to toxic substances such as heavy metals, pesticides, paint fumes, and cleaning solvents.
Doctors also advise pregnant women to avoid alcohol and cigarettes to reduce the risk of giving birth to children with health problems.
There is some evidence that dietary folic acid can reduce the likelihood of some birth defects that affect the brain and spine. Natural sources iof this vitamin include orange juice, green leafy vegetables, beans, peanuts, broccoli, asparagus, peas, and lentils.
The first detailed study of birth defects in developing countries concluded in 2006 that deaths and disabilities could be reduced by 70 per cent with cheap and effective measures.
It said governments should develop maternal- and child-health programmes to raise awareness among health workers and the public about the causes of birth defects and ways to them.
Unless very large numbers of birth defects occur in a short space of time – as in the case of the children born in conflict zones and the thalidomide babies (see above) – it is very difficult to link the health problems with any specific cause.
Journalists who suspect there is a cluster of birth defects should seek evidence from health officials or scientists to assess whether the numbers and type of defects are abnormal compared to a wider population.
They should bear in mind that in some areas, the reporting of birth defects might be inaccurate. A recent study in Brazil showed, for instance, that nearly half of all birth defects in one city were not recorded properly.
So journalists can also report on the measures that public health systems use to detect birth defects and whether or not they investigate their possible causes.
If a cluster is confirmed then reporters should look into the full range of possible explanations – such as expsoure to pesticides, whether mothers drink alcohol and smoke, and whether the population has been inbreeding.
CASE STUDY – Agent Orange in Vietnam
During the US-Vietnam War, the United States sprayed massive quantities of herbicide-based defoliants such as Agent Orange from the air to destroy tree cover.
In areas that were sprayed many women have given birth to children with birth defects, including physical abnormalities and mental disorders.
The herbicides were contaminated with a highly toxic chemical called TCDD, a form of dioxin, which has been shown in animal experiments to cause birth defects and many other diseases.
For an in-depth journalistic report on this story, see this Chicago Tribune article by Jason Grotto.