The many infants that are born prematurely every year often face a number of medical problems at birth, but according to a new study from Sweden even if they overcome those difficulties, which thanks to modern medical techniques many do, they still may face health difficulties later in their childhood – specifically asthma.

Researchers from the Karolinska Institutet, led by pediatrician and Assistant professor of medical epidemiology and biostatistics the prestigious institution Dr Catarina Almqvist Malmros, conducted their research using data culled from the Swedish Twin Registry, which contained the medical records of 10,918 twins. Specifically they were looking for the incidence of asthma amongst the children.

According to Dr Malmros their findings demonstrate a direct correlation between gestational age (the number of weeks a child is in the womb before birth) and fetal growth. These findings she said were independent of other influences such as environmental or genetic conditions that were adjusted for.

At the time the study data was collected all the participants were between the ages of nine and twelve, babies no longer, and some had developed asthma symptoms recently. The study appears to demonstrate though that this can be traced back in many cases to the twins’ premature arrival.

According to the World Health Organization there are more than 300 million people all over the planet who suffer from asthma, the numbers having risen significantly over the last decades. At the same time the number of recorded premature births has also risen, and asthma, again according to WHO, is the number one chronic disease in children. This data backs up the conclusions of the Karolinska Institutet study, that impaired fetal growth affects lung development.

These days a child deemed premature at birth can be anywhere between 25 and 38 weeks gestation. Even the 25 weekers can survive and thrive without medical problems but they all almost always experience breathing and temperature control problems at birth, requiring an ICU stay that may last for months.

According to a white paper published by the March of Dimes, a charitable organization that raises money and awareness about the issue of premature, or preterm birth, in the United States alone the incidence od premature birth has risen by 36% over the past 25 years. Globally the white paper states that there are over 12.9 million babies born early every year these days, and that surprisingly the rate of premature birth in North America (the US and Canada combined) is second only to Africa.

The causes of premature birth are numerous. A mother may have uterine or cervical complications, and many researchers are increasingly linking smoking, alcohol consumption and poor diet to a rise in the number of children born early.