Tuesday 3 December 2013

Preterm labor - Etiological factors

Preterm labor is one of the most common causes of neonatal morbidity and mortality.
Preterm labor defined by WHO as the onset of labor prior to the completion of 37 wks of gestation, in a pregnancy beyond 20 wks of gestation (28 wk according to Indian criteria).
Incidence of preterm labor is : 5 – 10%.
Preterm labor accounts for 75% of all perinatal deaths.
It becomes 85% when lethal congenital fetal anomalies are excluded.

Etiology of preterm labor: Socioeconomic factors:
Age of the woman: pregnant women with extremes of reproductive age are more prone for preterm labor.
Nutrition: both under nutrition and over nutrition can lead to preterm labor.
Occupation: pregnant women working in strenuous work may land up in preterm labor.
Psychosocial factors: pregnant women leading stressful life with psychological disturbances may go into preterm labor.
Lifestyle factors: Pregnant women who smoke are prone to preterm labor.

Genetic factors:
Pregnancies with babies having fetal mitochondrial bifunctional protein defects or having polymorphism in IL-1gene complex or in beta-adrenergic receptors or in TNF alpha may land in preterm labor.

Obstetric problems in present pregnancy:
Obstetric problems like preeclampsia, APH(ante partum hemorrhage), multiple pregnancy or hydramnios can lead to preterm labor.

Infections leading to preterm labor: Maternal infectios like febrile illness, syphilis & toxoplasmosis, chorioamnionitis - acute & subclinical, bacterial vaginosis can lead to preterm labor.
Extra uterine infections like, UTI(urinary tract infections), pneumonia, acute appendicitis, periodontal disease etc can also lead to preterm labor.

Maternal systemic diseases leading to preterm labor:
Maternal systemic diseases like renal diseases, cardiac disease, hypertension, diabetes,  immunological diseases, anemia etc can lead to preterm labor.

Structural abnormalities:
Women with uterine abnormalities or cervical incompetence are prone for preterm labor.

Past obstetric history:
Women with previous preterm labor, second trimester abortion, 3 or more first trimester abortions are vulnerable to preterm labor.

Other causes:
Other causes are like abnormal placentation, idiopathic causes, fetal causes etc.

Indicated preterm labor: Sometimes preterm labor is indicated in conditions like preeclampsia, severe IUGR(intra uterine growth retardation), APH, maternal DM(diabetes mellitus), heart disease, chronic renal disease etc., for saving the life of either mother or the baby.

Preterm labor-pathogenesis and diagnosis
Preterm labor-investigations
Preterm labor-prediction
Preterm labor-complications
Preterm labor -prevention
Preterm labor-bacterialvaginosis
Preterm labor-progesterone.html
Preterm labor-cervical circlage
Pretem labor-management
Preterm labor-tocolytics
Preterm labor-with premature rupture of membranes





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