Hadlock dating criteria
Early ultrasound examination, ideally at eight to 13 weeks of gestation, is more accurate for estimating gestational age than ultrasound assessment later in pregnancy.Although ultrasound assessment is used later in pregnancy to estimate fetal weight, ultrasound dating is only accurate to about three weeks when it is performed at term.Arrested head growth is of great concern to the developmental potential of the fetus.1A 22-year-old woman (gravida 1) presents to the physician who has been providing her prenatal care. At the 32-week visit, her blood pressure was 140/95 mm Hg and she had gained 2.25 kg (5 lb) since her last visit. Fundal height was 28 cm, unchanged from the measurement obtained at the 30-week visit.The physician suspects growth restriction secondary to the onset of preeclampsia.
The maternal-placental-fetal units act in harmony to provide the needs of the fetus while supporting the physiologic changes of the mother.Fetal growth restriction is the second leading cause of perinatal morbidity and mortality, followed only by prematurity.12 The incidence of intrauterine growth restriction (IUGR) is estimated to be approximately 5 percent in the general obstetric population.3 However, the incidence varies depending on the population under examination (including its geographic location) and the standard growth curves used as reference.4 In assessing perinatal outcome by weight, infants who weigh less than 2,500 g (5 lb, 8 oz) at term have a perinatal mortality rate that is five to 30 times greater than that of infants whose birth weights are at the 50th percentile.5 The mortality rate is 70 to 100 times higher in infants who weigh less than 1,500 g (3 lb, 5 oz).5 Perinatal asphyxia involving multiple organ systems is one of the most significant problems in growth-restricted infants.3Timely diagnosis and management of IUGR is one of the major achievements in contemporary obstetrics.If the growth-restricted fetus is identified and appropriate management instituted, perinatal mortality can be reduced,6IUGR is the pathologic counterpart of small-for-gestational-age.Asymmetric growth restriction implies a fetus who is undernourished and is directing most of its energy to maintaining growth of vital organs, such as the brain and heart, at the expense of the liver, muscle and fat.This type of growth restriction is usually the result of placental insufficiency.