Postnatal assessment of gestational age
- Tiffany M McKee-Garrett, MD
Tiffany M McKee-Garrett, MD
- Associate Professor of Pediatrics
- Baylor College of Medicine
Gestational age is determined in the fetus by menstrual history or ultrasound dating, and in the newborn by physical examination and neuromuscular assessment. This determination is used to assess intrauterine growth, make decisions about the timing of delivery in complicated pregnancies, and predict the infant's clinical course. The most accurate estimation of gestational age is achieved by considering prenatal date (ie, last menstrual period [LMP] and early ultrasound [if available]), in combination with physical and neurological features of the newborn.
●Gestational age (also called menstrual age or menstrual dating) is estimated in completed weeks from the date of the mother's last menstrual period (LMP).
●Estimated date of a term delivery (also known as estimated date of confinement [EDC]) is calculated by adding one year and seven days to the LMP and then subtracting three months. This calculation is known as Naegele's rule and assumes that ovulation occurs two weeks after the LMP.
●Ovulatory or fertilization age of the fetus is the presumed date of ovulation, and is two weeks less than gestational age measured from the LMP. Ovulatory age of the fetus is frequently used by embryologists.
LIMITATIONS OF ASSESSMENT
Accurate menstrual dating depends upon certain maternal knowledge of LMP and regular 28-day cycle length, and is considered to have an accuracy of ±2 weeks.
Subscribers log in hereLiterature review current through: Jul 2017. | This topic last updated: Sep 21, 2015.References
- Mittendorf R, Williams MA, Berkey CS, et al. Predictors of human gestational length. Am J Obstet Gynecol 1993; 168:480.
- Mittendorf R, Williams MA, Berkey CS, Cotter PF. The length of uncomplicated human gestation. Obstet Gynecol 1990; 75:929.
- Nguyen TH, Larsen T, Engholm G, Møller H. Evaluation of ultrasound-estimated date of delivery in 17,450 spontaneous singleton births: do we need to modify Naegele's rule? Ultrasound Obstet Gynecol 1999; 14:23.
- Amiel-Tison C. Neurological evaluation of the maturity of newborn infants. Arch Dis Child 1968; 43:89.
- Dubowitz LM, Dubowitz V, Goldberg C. Clinical assessment of gestational age in the newborn infant. J Pediatr 1970; 77:1.
- Dubowitz L, Ricciw D, Mercuri E. The Dubowitz neurological examination of the full-term newborn. Ment Retard Dev Disabil Res Rev 2005; 11:52.
- Sanders M, Allen M, Alexander GR, et al. Gestational age assessment in preterm neonates weighing less than 1500 grams. Pediatrics 1991; 88:542.
- Ballard JL, Novak KK, Driver M. A simplified score for assessment of fetal maturation of newly born infants. J Pediatr 1979; 95:769.
- Alexander GR, de Caunes F, Hulsey TC, et al. Validity of postnatal assessments of gestational age: a comparison of the method of Ballard et al. and early ultrasonography. Am J Obstet Gynecol 1992; 166:891.
- Ballard JL, Khoury JC, Wedig K, et al. New Ballard Score, expanded to include extremely premature infants. J Pediatr 1991; 119:417.
- Donovan EF, Tyson JE, Ehrenkranz RA, et al. Inaccuracy of Ballard scores before 28 weeks' gestation. National Institute of Child Health and Human Development Neonatal Research Network. J Pediatr 1999; 135:147.
- Parkin JM, Hey EN, Clowes JS. Rapid assessment of gestational age at birth. Arch Dis Child 1976; 51:259.
- Allan RC, Sayers S, Powers J, Singh G. The development and evaluation of a simple method of gestational age estimation. J Paediatr Child Health 2009; 45:15.
- Verhoeff FH, Milligan P, Brabin BJ, et al. Gestational age assessment by nurses in a developing country using the Ballard method, external criteria only. Ann Trop Paediatr 1997; 17:333.
- Hittner HM, Hirsch NJ, Rudolph AJ. Assessment of gestational age by examination of the anterior vascular capsule of the lens. J Pediatr 1977; 91:455.
- Hittner HM, Gorman WA, Rudolph AJ. Examination of the anterior vascular capsule of the lens: II. Assessment of gestational age in infants small for gestational age. J Pediatr Ophthalmol Strabismus 1981; 18:52.
- Hughes JR, Fino J, Gagnon L. Periods of activity and quiescence in the premature EEG. Neuropediatrics 1983; 14:66.
- Eyre JA, Nanei S, Wilkinson AR. Quantification of changes in normal neonatal EEGs with gestation from continuous five-day recordings. Dev Med Child Neurol 1988; 30:599.
- Tharp BR. Electrophysiological brain maturation in premature infants: an historical perspective. J Clin Neurophysiol 1990; 7:302.
- Hayakawa M, Okumura A, Hayakawa F, et al. Background electroencephalographic (EEG) activities of very preterm infants born at less than 27 weeks gestation: a study on the degree of continuity. Arch Dis Child Fetal Neonatal Ed 2001; 84:F163.
- Tharp BR. Electroencephalography in the Assessment of the Premature and Full-Term Infant. In: Fetal and Neonatal Brain Injury, Stevenson DK, Sunshine P (Eds), BC Decker Inc., Philadelphia 1989. p.175.
- Scher MS, Barmada MA. Estimation of gestational age by electrographic, clinical, and anatomic criteria. Pediatr Neurol 1987; 3:256.
- Scher MS, Martin JG, Steppe DA, Banks DL. Comparative estimates of neonatal gestational maturity by electrographic and fetal ultrasonographic criteria. Pediatr Neurol 1994; 11:214.
- Scher MS, Sinha S, Martin J, Steppe DA. Estimation of gestational maturity of preterm infants by five fetal sonographic measurements compared with neonatal EEG and the last menstrual period. Electroencephalogr Clin Neurophysiol 1995; 95:408.