The small fetus: Growth-retarded and preterm Obstetric problems in the developing world

Abstract

A low-birthweight baby is defined as an infant weighing 2500 gm or less, although this definition is not adequate for all groups, especially in developing countries. In Singapore, for example, it is more realistic to define a low-birthweight baby as 2270 gm or less. A preterm baby is one born before 37 weeks of gestation. A small-for-gestational-age baby is one that is below the tenth percentile as defined by birthweight and gestational age. A high incidence of low-birthweight babies creates a heavy public health burden in developing countries, both in terms of infant mortality and in terms of life-time care for those that survive but are physically or mentally handicapped. Low-birthweight babies fall into 2 categories: those with fetal growth retardation and those which are preterm. Fetal growth retardation may be due to placental insufficiency; loss of growth capability by the fetus; or infectious diseases, smoking or betel chewing. Diagnostic signs of fetal growth retardation can be inferred from the level of the fetal head, the amount of liquor, premature cervical ripening, and poor or absent maternal weight gain. Low values of urinary estrogen or plasma estriol may serve as indicators, as may low urinary levels of human placental lactogen. Decrease in fetal movement is a sign of fetal distress. Level of fetal growth may also be determined by ultrasonography and antepartum cardiotocography. Preterm birth accounts for 75% of perinatal deaths. 10%-30% of those that survive are handicapped, but over 2/3 of all deaths in the 1st week of life occur in perfectly formed babies that are simply born too soon. Preterm birth may be due to a low socioeconomic environment, elevated estrogens and decreased progesterone; obstetric complications, such as pre-eclampsia, abruptio placentae, polyhydramnios, or infection; increased prostaglandins and premature rupture of fetal membranes; cervical incompetence; developmental errors; or multiple pregnancy. In Singapore several groups of women at high risk for premature delivery were treated with beta-adrenergic drugs and steroids or with cervical cerclage. Improved socioeconomic conditions in Singapore have resulted in a decrease in the number of low-birthweight babies.