A study has found that there is an increased risk of premature birth in women who themselves were born early.
The risk of a woman's first baby being born early is 60% higher if she, or a sibling, was born prematurely. And the risk is 50% higher for subsequent children.
The research has come from a team at the University of Aberdeen, who studied mothers and daughters in the city over 60 years, looking at records dating back to 1948.
They were trying to explain what may cause early births, which carry the risk of long-term problems including cerebral palsy. More research is needed, they concluded, to determine if there is such a genetic connection.
Dr Sohinee Bhattacharya, lecturer in obstetric epidemiology at the university, led the study. She said: "Women born pre-term or with siblings delivered in a similar manner have an increased risk of spontaneous pre-term delivery in their own pregnancies.
"Pre-term birth is the leading cause of death and long-term ill-health in babies and children in the developed world. Attempts to predict and prevent spontaneous pre-term births are compromised by gaps in our understanding of what causes the condition.
"Accurate prediction of risk would also help in planning appropriate antenatal care in women deemed to be at high risk.
"Our research supports a genetic predisposition to pre-term birth. Further research should focus on the identification of candidate genes for the condition."