Indian scientists unlock preterm birth mystery

Indian researchers have made a major discovery by understanding the mechanisms by which preterm births (between 28 and 32 weeks of gestation) occur. At 35%, India accounts for the highest burden of preterm births in the world.

What has been discovered?

The researchers found that gram-positive Group B Streptococcus (GBS) bacteria produce small balloons called membrane vesicles, which contain toxins that kill both foetal and maternal cells and destroy the collagen that binds the cells together.

• The researchers found that the toxins present in the vesicles fragmented the collagen of the amniotic membrane. 
• Fragmentation of the collagen leads to loss in elasticity and weakening of the amniotic membrane thus making it susceptible to rupture due to pressure from the growing foetus. 
• This leads to preterm birth. The vesicles also degrade the collagen in the womb.

GBS Bacteria:

Group B Streptococcus (GBS) bacteria are normally found in human vagina and their numbers can shoot up in some pregnant women. 

• The GBS bacteria have been associated with premature rupture of amniotic membrane and preterm birth.

How the study was carried out?

The scientists tested hypothesis by injecting vesicles into 15 pregnant mice. All the injected mice gave birth to preterm babies and nearly 40 per cent were born dead (stillborn). The preterm babies were much smaller and unhealthy. 

• In mice, the babies were born two days preterm. This is equivalent to two months in humans as the gestation period in mice is 21 days.

What is preterm birth?

Preterm, also known as premature birth is a birth that takes place more than three weeks before the baby is due. In other words, a premature birth is one that occurs before the start of the 37th week of pregnancy. 

• Normally, a pregnancy usually lasts about 40 weeks. Premature birth gives the baby less time to develop in the womb.