World Health Organization (WHO) defines preterm as:
“Babies born alive before 37 weeks of gestation”.
How common is it?
The frequency of preterm birth (before 37 weeks of gestation) is about 5โ9% in developed countries and has been on the rise for many years. Early preterm birth (before 32 weeks of gestation) is less common than preterm birth, but it carries the highest risk for morbidity and mortality.
What are the risk factors?
There are multiple maternal and fetal risk factors for preterm delivery:
- Previous preterm birth: The risk for recurrent preterm birth is influenced by prior gestational duration. The smaller the gestational age of the previous pregnancy, the higher the risk for a subsequent preterm birth.
- Multiple gestations: This carries a huge risk of preterm delivery, accounting for 15โ20% of all preterm births.
- Polyhydramnios/Oligohydramnios: Too much or too little amniotic fluid is associated with preterm labor. This can easily be ruled out during antenatal scans.
- Pre-eclampsia or eclampsia: These are the serious complications of pregnancy. Prompt blood pressure control during pregnancy can prevent these conditions from resulting in preterm delivery.
- Chorioamnionitis: This inflammatory condition is a major risk factor for preterm birth. Early diagnosis through clinical symptoms is beneficial.
- Physiological/Mental Stress: Women exposed to stressful conditions during pregnancy are thought to have increased serum concentrations of inflammatory markers such as C-reactive protein.
- Low maternal body mass index (BMI): Pregnancies in underweight women have been associated with all sorts of adverse outcomes, including preterm births.
- Short cervical length: A short cervical length before 24 weeks of gestation is predictive of spontaneous preterm birth.
- Physical stress: Observational studies suggest that pregnant women doing hard physical labor under stressful environments are more likely to deliver a preterm baby.
- Placenta previa: It contributes to about 5% of all preterm deliveries. Vaginal bleeding occurring in women with placenta previa further increases the chance of preterm birth.
- Placental abruption: Women diagnosed with placental abruption are at a sixfold increased risk of preterm delivery.
- Vaginal Infections: Bacterial vaginosis and candidiasis can both trigger preterm labor.
- Maternal abdominal surgery: If performed in the second or third trimesters, it can stimulate contractions leading to preterm delivery.
- Maternal medical disorders: Thyroid disease, asthma, diabetes, and hypertension, are associated with increased rates of preterm delivery.
How recurring preterm birth can be?
A retrospective study was conducted in California from 2005 to 2011. It included 163,889 women who delivered their first and second child between 20 and 44 weeks of gestation in the same hospital. To check the prevalence of preterm births, data from hospital discharge records and birth certificates were used. It was concluded that shorter gestational duration in the first pregnancy potentially increased the risk of a subsequent preterm birth.
An insight from mamahood
Dear mama, prematurity has now emerged as a global health concern. It is the leading cause of perinatal morbidity and mortality in developed countries. This surge in preterm delivery is mainly due to an escalation in environmental & biological factors. Spreading awareness regarding the risk factors is a reasonable goal. It not only identifies the likelihood of preterm delivery in a woman but also gives an insight into the early management of preterm birth.
