Study finds genetic link to premature birth

Researchers from Finland and the USA have identified a gene linked to an increased risk of premature birth. Previous research has looked at the mechanisms for synchronising fetal maturation and birth in animals, but no human equivalents were found, and the cause of premature births remained unknown.

In this new study published in PLoS Genetics, the researchers took a different approach and decided to compare the human genome to other mammals such as the chimpanzee, rat and mouse to identify candidate genes, and then looked to see if any of these human genes were correlated with premature birth.

Professor Louis Muglia, a senior researcher on the study from Vanderbilt University in the USA, said that humans have the shortest gestation period of any primate when brain and body size is considered, and suspected that there must be a genetic explanation for premature birth. Premature birth affects around ten percent of babies in the UK, and is defined as a birth which occurs before 37 weeks.

Professor Muglia and his team predicted that having relatively large heads and narrow birth canals in comparison to other primates would favour the evolution of a shorter gestation period in humans, meaning babies were smaller at the time of birth.

During their analysis, they looked for genes that showed signs of 'accelerated evolution' relative to their primate equivalents and found 150 potential candidates. The researchers then looked for these candidate genes in a group of 328 Finnish mothers who had had a premature birth.

The researchers found one candidate stood out, the gene for the receptor for follicle-stimulating hormone (FSH). FSH stimulates the development of follicles, clumps of cells produced in the ovaries that contain an egg and also help to regulate the production of another hormone, oestrogen. FSH was not previously thought to have a role in labour.

The team also found the same correlation in another group, this time consisting of African American women.

Professor Muglia hopes to expand the study and look at other population groups, as well as investigating the role of FSH and its receptor in birth timing. He told the BBC: 'Ideally we'd like to predict which women are at greatest risk for having pre-term birth and be able to prevent it. That would really have an impact on infant mortality and the long-term complications of being born prematurely'.