The number of premature births has increased 16% over the last 25 years, research has shown.
High blood pressure is the main factor linked to early labour, while diabetes was recognised as playing an increasing role.
But medical advances mean that survival rates have significantly improved and the number of baby deaths associated with premature birth has halved.
Researchers from the University of Edinburgh analysed data from nearly 90,000 births in Scotland between 1980 and 2005.
The number of babies born prematurely increased from 54 per 1,000 births between 1980 and 1985 to 63 per 1,000 births between 2000 and 2005.
Scientists hope to develop better treatments for expectant mothers by exploring the trends associated with premature birth and its causes.
There has been a seven-fold increase in premature births where the mothers were diabetic before becoming pregnant.
Premature births linked to gestational diabetes, where expectant mothers develop diabetes during pregnancy, also increased by four times.
High blood pressure remained the major factor linked to premature births but the number of babies born prematurely as a result of the condition dropped. Survival rates of premature babies were greater when births were medically induced or took the form of pre-planned Caesarean section rather than those where labour occurred naturally.
