POOR nutrition around the time of conception can trigger premature birth, according to a study of pregnant sheep. If the same is true for people, a bad diet could account for some of the 40 per cent of premature births that remain unexplained each year in developed countries.
Premature birth is by far the most common cause of neonatal death, and its incidence in Western societies has increased in the past decade. Previous studies have found that reduced maternal nutrition 鈥� in women with anorexia, for example 鈥� can cause lower birthweight in babies born after the full gestation period. But 鈥渢his is the first clear demonstration of a link between nutrition around the time of conception and the length of gestation鈥�, says Frank Bloomfield of the University of Auckland, New Zealand, who led the work.
The researchers fed 10 ewes mild to moderately restricted diets for two months prior to conception and one month afterwards. Compared with eight sheep that had free access to food, all the undernourished sheep delivered their lambs earlier, and half of their deliveries were classed as premature (Science, vol 300, p 606).
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The team also studied hormonal fluctuations. Prior to birth, there is a surge in fetal levels of the stress hormone cortisol. This surge, which is important for triggering labour in people as well as sheep, happened earlier in the fetuses of the undernourished ewes.