Adults born premature are twice as likely to remain life-long virgins compared to babies born at full-term, research suggests.

Analysis of studies covering up to 4.4 million adult participants has shown that those who were born pre-term are less likely to form romantic relationships, have sex or experience parenthood than those who were born full-term.

Researchers at the University of Warwick believe this is partly due to premature birth being associated with people who are more withdrawn and shy, socially excluded and less likely to take risks in adolescence.

The analysis found that those born pre-term were 28% less likely to form a romantic relationship and 22% less likely to become parents, when compared to those born full-term.

In the studies that looked at the sexual relations of pre-term children, they were 2.3 times less likely to ever have a sexual partner when compared to full-terms.

Those born before the 28-week mark were more than three times less likely to have sex, according to the paper, published in JAMA Network Open.

When adults born prematurely had friends or a partner, the quality of these relationships was not diminished compared to those born full term.

First author of the paper, Dr Marina Goulart de Mendonca from the university’s psychology department, said: “The finding that adults who were born pre-term are less likely to have a partner, to have sex and become parents does not appear to be explained by a higher rate of disability.

“Rather, preterm-born children have been previously found to have poorer social interactions in childhood that make it harder for them to master social transitions such as finding a partner, which in turn is proven to boost your wellbeing.”

The study’s authors said lack of sexual and romantic relationships may lower wellbeing and lead to poorer mental and physical health.

They added the findings did not support the theory that adults born prematurely take longer to achieve the milestones that make up adult life.

They wrote: “We verified that the difference of experiencing these transitions in comparison to (those born full-term) did not alter in the older age group, and in some cases, it was even higher in the older age group.”

Dr Chiara Nosarti, a reader in Neurodevelopment & Mental Health at the Institute of Psychiatry, Psychology & Neuroscience, said: “Several studies have investigated pre-term individuals’ social outcomes at different stages of life and the general consensus across studies is that social adjustment difficulties following pre-term birth emerge in childhood and remain throughout the lifetime.”

She added: “Studies investigating the specific cognitive and behavioural processes that pre-term birth/low birth-weight individuals use to adapt their responses to people and situations, ie social skills, have reported poorer attention, ability to co-operate with others, to interpret body language and to regulate one’s emotions.”