Bacteria may play a role in preterm premature rupture of fetal membranes, reveal researchers. This finding was published online in the recent edition of PLOS ONE.
Preterm delivery is when the baby is delivered before 37 weeks of pregnancy. Preterm delivery puts the baby at a number of health risks and may even affect the survival of the baby. Thus, it is necessary to understand various reasons for preterm delivery and control them where possible.
AdvertisementRecent research suggests that preterm premature rupture of membranes (PPROM), which could trigger preterm delivery, could be possibly due to bacteria. Normally, fetal membranes - the chorion and the amnion - surround the fetus and the amniotic fluid. A break in the membranes, also referred to as breaking of the bag of waters, is often followed by the delivery of the fetus.
The study included 48 women, who were divided into three groups. The first group consisted of women with PPROM between 24 to 34 weeks of gestation which was confirmed by various tests. The second group consisted of 16 preterm women between 24 to 34 weeks of gestation, who either underwent labor or delivered by cesarean section. The third group consisted of 18 term women between 37 to 41 weeks of gestation who again either underwent labor or delivered by cesarean section.
Fetal membranes were collected from the rupture site after delivery in those who underwent labor and a site over the cervix in those who underwent caesarian section. Another sample was also collected from an intact site far away from the rupture site, referred to as the distant site. Membrane thickness was measured in each case. The Fluorescence in situ Hybridization (FISH) test was used to detect the presence of bacteria in the samples.
In the PPROM group, the mean time duration from the rupture of membranes to the delivery was 13.1 days. Antibiotics were given following the rupture for around 7 days.
The researchers found that the chorion layer of the fetal membranes was thinner at the site of rupture in all patients as compared to the distant site. Patients with PPROM had thinning of the chorion at the rupture site as well as the distant site, indicating an overall thinning of the membrane in patients with PPROM.
The mean bacterial count was higher at the rupture site than the distant site in all patients. Though all the samples had bacteria present, the counts were higher in those with PPROM. Higher bacterial counts were associated with thinner chorion in these patients.
The study thus suggests that that the chorion layer of the fetal membrane is thinner in patients with PPROM throughout the fetal membrane. It also suggests that bacteria may play a role in the thinning of the chorion layer.
The researchers suggest that further studies should be done to identify the bacteria found in PPROM patients. If specific bacteria are found to be associated with PPROM, diagnosing and treating such as infection during pregnancy could possibly reduce the chances of premature birth and therefore its consequences.
Causes of Premature Birth
The exact cause of premature birth is not known. Some of the factors that increase the risk of premature birth are:
• Illnesses like pre-eclampsia, kidney disease and infections in the mother
• Smoking, drug abuse or excessive intake of alcohol
• A weak cervix, the lower part of the uterus
• Placenta previa, a condition where the placenta is located lower than normal
• Multiple fetuses
• Physical injury or mental stress
1. Fortner KB et al. Bacteria Localization and Chorion Thinning among Preterm Premature Rupture of Membranes. DOI: 10.1371/journal.pone.0083338