The premature aging of the placenta due to oxidative stress may be responsible for several preterm births, a new study finds.

Preterm birth is defined as delivery of a baby prior to the 37-week gestation period. Previous studies have highlighted many health issues associated with this type of birth. Shedding more light on this occurrence, researchers from the University of Texas found that the premature aging of the placenta due to oxidative stress may be responsible for the increasing number of preterm births that have taken place over the last few decades.

"This is the first study to look at and prove that oxidative stress induces senescence or aging in human fetal cells," said Dr. Ramkumar Menon, lead researcher of the study, in a statement. "With more than 15 million pregnancies worldwide ending in preterm births, we can now move forward in discovering how this information may help in formulating better intervention strategies to reduce the risk of preterm births."

Oxidative stress factors include various toxins and pollutants that expecting mothers are exposed to on a daily basis. It also includes smoking and drinking, high body mass index, poor nutrition and infection. For this study, researchers subjected fetal membranes to oxidative stress in a lab setting and found that it aged the placenta.

Generally, the body is capable of producing anti-oxidants that rectify damages caused by oxidative stress. However, when these damages extend beyond a certain point, it leads to aging of the placenta. This can lead to the baby not getting the nutrients it needs to survive, causing it to be delivered prior to term. Often the placenta is calcified, which makes parts of it to die and no longer be useful. Placenta aging can also occur due to a type of bacteria called Nanobacteria.  

Researchers are yet to determine how this stress damages the placenta - a reason why anti-oxidant supplements taken during pregnancy has failed to reduce the number of premature births.

According to the World Health Organization, 15 million babies are born before term every year and this number is still rising. The WHO also revealed that more than one million babies die due to premature complications and preterm birth remains the leading cause of death among newborn babies.

Fortunately, more than three-quarters of premature babies can be saved with feasible, cost-effective care - even without neonatal intensive care.

The health implications of being born preterm are several. In March this year, researchers found that preterm birth increases the risk of asthma by 70 percent. Another study conducted last August found that premature babies are at a higher risk of developing heart diseases as adults. Other health problems that the babies may face later in life include jaundice, anemia, heart murmurs, Retinopathy of Prematurity (ROP), apnea and bradycardia, Chronic Lung Disease/Bronchopulmonary Dysplasia (BPD) and Respiratory Distress Syndrome (RDS).

The new study was published in the American Journal of Pathology.