ENDOCRINOLOGY OF PARTURITION AND PREPARATION FOR LABOUR

Abstract

Parturition is the process leading to expulsion of the fetus from the uterus. It is the result of a co-ordinated interplay between maternal and fetal factors. Despite extensive research the mechanisms that control the length of human pregnancy and signal the onset of labour remain unknown. Preterm labour refers to the onset of labour before 37 completed weeks or 259 days of pregnancy and after the gestation of viability (20–25 weeks, depending on definition). In most developed countries, preterm birth occurs in 5–10% of pregnancies whereas this may rise to 25% in certain developing countries. Despite advancing knowledge of risk factors and the introduction of beneficial medical and public health interventions the incidence of preterm birth rate has risen over the last two decades. Preterm birth is the single biggest cause of perinatal mortality. Adverse outcomes for the neonate include respiratory complications, necrotizing enterocolitis, sepsis and neurodevelopmental disorders. Among those babies born before 30 weeks who survive, approximately 25% will have a major disability. Another 10% will have some disability and an additional 30% will have cognitive, perceptual and behavioural problems that could interfere with school performance. The consequences of prematurity are not confined to the neonate but have important long-term social, financial, behavioural and educational implications.