BBC News reported on a major study of over a million mothers in Denmark. After analysing their records, it was found that mothers who experienced extreme stress in the 6 months before becoming pregnant increased the risk of birth before 33 weeks by 59%. Serious illness or death of older children were among the stressors examined, along with death or illness of other close family members. The researchers suggested the possibility that increased stress hormones or lifestyle changes (such as increased substance use) might be responsible for the premature deliveries.
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