The National Human Genome Research Institute study confirmed previous findings linking high cholesterol to a raised risk of premature birth. But the researchers were surprised to find low cholesterol levels also seemed to raise the risk.
The researchers examined more than 1,000 women from South Carolina and their newborn babies. They found 5% of women with moderate cholesterol levels gave birth prematurely.
In contrast, the prematurity rate among women with the highest cholesterol levels – more than 261milligrams per decilitre (mg/dl) – was about 12%. But among women with the lowest cholesterol levels – less than 159mg/dl – it was 21%.
The researchers found no difference in the rate of birth defects – but women with very low cholesterol were more likely to give birth to babies with a smaller head size.
Lead researcher Dr Max Muenke said more research was needed to confirm the findings.
“Based on our initial findings, it appears that too little cholesterol may be as bad as too much cholesterol during pregnancy, but it is too early to extrapolate these results to the general population.”
“The right amount of cholesterol is fundamental for good health, both before and after birth.
“During pregnancy, cholesterol is critical for both the placenta and the developing baby, including the brain.”
Low maternal cholesterol levels can be related to a woman’s genetic make-up, but also factors such as diet.