Preterm birth and licorice consumption during pregnancy.

Heavy licorice (glycyrrhizin) consumption has been associated with shorter gestation. The aim of the present study was to test whether this association also applies to preterm (<37 weeks) births. In 2000-2001, a sample of 95 Finnish women who delivered preterm singletons was compared with controls (n = 107) who delivered babies of normal gestational age in the same hospital. Glycyrrhizin intake was calculated from questionnaires containing detailed items on licorice consumption. Glycyrrhizin exposure was grouped into three levels: low (<250 mg/week), moderate (250-499 mg/week), and heavy (> or =500 mg/week). Heavy consumption versus a lower level of consumption was associated with a more than twofold increased risk of preterm (<37 weeks) delivery. The association was stronger when only the 40 births classified as early preterm delivery (<34 weeks) were included (odds ratio = 3.07, 95% confidence interval: 1.17, 8.05 for the fully adjusted model). In conclusion, heavy glycyrrhizin exposure was associated with preterm delivery and may be a novel marker of this condition.