Warning over pregnancy lead levels
Women should stay healthy during pregnancy to keep children’s lead levels low, new research suggests.
The findings from the Children of the 90s study at the University of Bristol shows that mothers who drank alcohol and coffee, smoked and had a coal fire in their home during pregnancy were likely to have higher levels of lead in their blood than women who did not.
Lead is a toxin that can cause high blood pressure in pregnancy, which in turn can predispose women to pre-eclampsia during pregnancy and heart disease later in life.
It accumulates in the bones and can remain for up to 30 years, the researchers said.
Exposure to high levels of lead while in the womb, when it is transferred from the mother, can affect the unborn baby’s developing nervous system.
It can also have a longer-term detrimental effect on the child’s health, academic performance and behaviour.
Lead is widespread in the environment, particularly in areas with smelters, lead works, and battery manufacturing and recycling. Other sources of exposure include food, water, dust and soil.
There are no recommendations for blood lead levels in pregnancy and childhood in the UK but the Centres for Disease Control and Prevention in the US recommend levels are kept below five micrograms per decilitre.
The Children of the 90s study is a long-term health research project which involves more than 14,000 mothers who were pregnant in 1991 and 1992.
Academics have followed the health and development of the women and their children in detail ever since.
This study looked at 4,285 mother-child pairs in the Children of the 90s study and found that women with blood lead levels above five micrograms per decilitre were more likely to have attended university, and to smoke and consume alcohol and coffee.
The researchers say the unexpected finding that higher educational levels were associated with higher lead levels supports recent evidence that it should not be assumed that more disadvantaged populations have higher exposure to environmental pollutants.
The study produced some other unexpected findings:
- The average blood lead level in this group of pregnant women is higher than has been found in similar groups in other developed countries.
- Women who had lived in the area of Avon all their lives had lower blood lead levels than those who had not.
- Women of Indian, Pakistani and Bangladeshi ethnicity had higher blood lead levels than white women.
Although the analysis was conducted on data gathered in 1991, it is the largest study of blood lead levels undertaken in the UK.
Levels in pregnancy in the UK have only been reported four times in the past.
Dr Caroline Taylor, the lead author, said: “Pregnant women should not be concerned by this new report.
“Our research reinforces the current advice to women who are pregnant or planning a pregnancy that they should stop or reduce their alcohol and caffeine intake and give up smoking if they can.
“They should follow a healthy diet with good sources of calcium and iron.
“Even though lead levels may have dropped since our data were gathered in 1991, due to the removal of lead from paint and petrol, there is no existing evidence to back this up in the UK.
“Our research highlights the need for an up-to-date study of lead levels in pregnant women in the UK.”
- The findings are published in the academic journal PLOS One.
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