A landmark study has revealed that babies born with low weight are more likely to go through depression and anxiety in later life.
The study led by Ian Colman of the University of Alberta's School of Public Health suggest that conditions in the womb indeed have an effect on the child's future development.
Colman said that people with symptoms of depression and anxiety were found to have low birth weight. "We found that even people who had just mild or moderate symptoms of depression or anxiety over their life course were smaller babies than those who had better mental health," said Colman. "It suggests a dose-response relationship. As birth weight progressively decreases, it's more likely that an individual will suffer from mood disorders later in life."
Researchers analysed the data provided by Medical Research Council National Survey of Health and Development, which is one of the longest-running survey in the world. It was carried out on more than 4,600 people born in Great Britain in 1946 for symptoms of anxiety and depression over a 40-year period whose symptoms were measured at 13, 15, 36, 43 and 53 years of age. Another interesting breakthrough was people who had worse mental health throughout their lives had also learnt standing and walking for the first time later in life.
"One of the surprising findings from our research, Colman said, was that people who had worse mental health throughout their lives had also reached developmental milestones—like standing and walking for the first time—later in life than those who had better mental health."
The researchers underlined that not all small babies will experience poor mental health in the future. "Being born small isn't necessarily a problem. It is a problem if you were born small because of adverse conditions in the womb—and low birth weight is what we looked at in this study because it is considered a marker of stress in the womb," he added. "When a mother is really stressed, blood flow to the uterus is restricted and the foetus gets fewer nutrients, which tends to lead to lower birth weight. "
The stress hormones pass through the placenta to the foetus and in turn might affect the foetus's neurodevelopment and stress response as a result the mind of the child does not develop properly. "Under these conditions, the part of the child's brain that deals with stress could be programmed incorrectly in utero—the brain doesn't develop as it would under ideal circumstances. If this theory is correct, you would find that when stressful events occur, the people who were smaller babies would be more likely to become depressed or anxious," Colman said further.
Colman suggests that better care should be taken of pregnant women and the kind of stress that pregnant mothers are under has a significant long-term effect on the developing foetus.
The study is published in the December 2007 issue of Biological Psychiatry.