The likelihood of a person committing suicide is partly determined as early as at birth, researchers believe.
Babies born with a low birth weight are twice as likely to commit suicide, the report says
The Swedish team looked at 700,000 adults and found low birthweight and being born to a teenage mother meant a two-fold rise in suicide risk.
The report also said risk increased for shorter babies.
The authors, from the National Centre for Suicide Research and Prevention in Stockholm, said it proved genetics played an important role in suicides.
The researchers followed the adults, who were all born between 1973 and 1980, and assessed the proportion of suicides and attempted suicides between 10 and 26 years of age.
The overall suicide rate in Sweden in 1999, when the follow-up exercise finished, was around 20 per 100,000 of the population.
Babies weighing 2kg or less were more than twice as likely to commit suicide as adults than those weighing between 3.25kg and 3.75kg, according to the findings published in The Lancet medical journal.
Children born to mothers under 19 years old were also more than twice as likely to commit suicide as those born to women aged 20 to 29.
The report said babies 47cm and under were significantly more at risk of suicide than those 50cm to 51cm.
Suicide risk also increased for those born to mothers who did not proceed beyond secondary school or had had at least three other children.
Dr Danuta Wasserman, who led the research,, said: "This study does not give the definitive answer to why people commit suicide but it does underline the important role pre-birth and maternal factors play.
"I think genetics and environmental factors play a role.
"But it is clear we need to give mothers more support during pregnancy, I think that is the most important message."
The report said factors such as nutrition and alcohol and drug abuse played a key role in determining birth weight and length.
And Dr Wasserman, who has edited a book on suicide prevention called Suicide and Unnecessary Deaths, also suggested maternal mental ill-health might affect growth.
Marjorie Wallace, the chief executive of mental health charity Sane, welcomed the report.
"We believe that when someone's mental and emotional fragility leads them to take their own life, the causes are like all conditions partly genetic and partly environmental, a mix of inner and outer stresses.
"Any research that throws light on the reasons why some people are more vulnerable than others is essential.
"With suicide rates, particularly among young men, still at a disturbingly high level, research of this kind is urgent to prevent the often unnecessary loss of life."