was also mounted to assess how reliably paediatric. staV could assess the gestational age of babies born to mothers with certain obstetric dates under service. Pages: 6. You must login or register to post new entries. RSS feed «Which statement about obstetric dating and assessment is correct». Prenatally, the date of the Last Menstrual Period (LMP) and abdominal ultrasound .. Assessment of Gestational Age at birth when obstetric gestation is known.
These criteria are considered easier to determine and more reliable than neurological criteria and have been recognized by various authors as valuable markers of foetal maturation. The system was found to be more objective and reliable than the method of trying to base gestational age on the presence or absence of individual criteria as had been the practice of previous authors.
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They combined the eleven physical criteria described by Farr8 and subsequently by Dubowitz44into six observations. They also combined the most useful neurological criteria used by Amiel-Tison43 involving passive rather than active muscle tone and including resting posture, angles of flexion, resistance to extension and passive recoil.
The criteria combined were those that had a high intercorrelation. The resulting simplified scoring method consisted of six physical and six neurological criteria. Ballard estimates of gestational age correlated strongly with estimates derived from Dubowitz44 scoring and from menstrual dates. This simplified scoring system is performed more easily and in less time than that required in performing the complete Dubowitz examination.
Problems with implementation and accuracy of neurological methods have been reported. They are more difficult, especially for non pediatricians to perform and inter-observer reliability is poor.
This can lead to an overestimation of the neurological gestational age. Parkin and co-workers,13 using four external criteria in a study of predominantly full term infants, reported that neurological scores correlated less well with true gestational age, were more affected by post natal age at time of examination, and exhibited poorer interscorer agreement.
Other authors, comparing the method of Parkin,13 classical Dubowitz44and Dubowitz physical criteria alone, also found that the Parkin13 method was easier and quicker to perform and appeared more accurate than the classical Dubowitz method,44 and as accurate as Dubowitz physical criteria in postnatal assessment of gestational age. However, Brueton and colleagues,10 surprisingly found that skin colour and opacity were useful criteria in African newborns especially when examined within a few hours of birth when they were still pink.
Feresu at al14 also reported that assessing skin colour in African newborn babies is problematic especially more than 48 hours after birth. The Ballard score45 has been reviewed to confirm that the score is not influenced by racial factors and that the physical components of the score seem to be more useful than those that rely on tone and posture.
Several authors have also reported different methods using different physical and neurologic criteria to assess gestational age, each trying to provide what best would suit his locality. For example, Eregie53in Benin City, Nigeria, developed a six-feature model which included head circumference, mid-arm circumference, skin texture, ear form, breast size and genitalia.
This model was found to have comparable accuracy with the Dubowitz method44 and has been suggested as an appropriate clinical tool for rapid and reliable maturity determination in healthy and sick newborn infants. Charts demonstrating each of these various clinical methods of post natal gestational age assessment are readily available in many clinical settings and on the internet and so can easily be applied in any setting which caters for newborn babies.
Conclusion Assessment of gestational age in the newborn is an age old practice and an important aspect of newborn care. There are several methods, many of which have been highlighted. Even in resource poor settings, one of several methods can be used to estimate gestational age and thus aid in the care of the newborn.
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Methods for Estimating the Due Date - ACOG
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Dev Med Child Neurol ; 8: Studies on maturity in newborn infants VI. Likewise, the EDD for a day-3 embryo would be days from the embryo replacement date. Clinical Considerations in the Second Trimester Using a single ultrasound examination in the second trimester to assist in determining the gestational age enables simultaneous fetal anatomic evaluation.
With rare exception, if a first-trimester ultrasound examination was performed, especially one consistent with LMP dating, gestational age should not be adjusted based on a second-trimester ultrasound examination.
Ultrasonography dating in the second trimester typically is based on regression formulas that incorporate variables such as the biparietal diameter and head circumference measured in transverse section of the head at the level of the thalami and cavum septi pellucidi; the cerebellar hemispheres should not be visible in this scanning plane the femur length measured with full length of the bone perpendicular to the ultrasound beam, excluding the distal femoral epiphysis the abdominal circumference measured in symmetrical, transverse round section at the skin line, with visualization of the vertebrae and in a plane with visualization of the stomach, umbilical vein, and portal sinus 8 Other biometric variables, such as additional long bones and the transverse cerebellar diameter, also can play a role.
Date changes for smaller discrepancies 10—14 days are appropriate based on how early in this second-trimester range the ultrasound examination was performed and on clinician assessment of LMP reliability. Because of the risk of redating a small fetus that may be growth restricted, management decisions based on third-trimester ultrasonography alone are especially problematic; therefore, decisions need to be guided by careful consideration of the entire clinical picture and may require close surveillance, including repeat ultrasonography, to ensure appropriate interval growth.
The best available data support adjusting the EDD of a pregnancy if the first ultrasonography in the pregnancy is performed in the third trimester and suggests a discrepancy in gestational dating of more than 21 days. Conclusion Accurate dating of pregnancy is important to improve outcomes and is a research and public health imperative. As soon as data from the LMP, the first accurate ultrasound examination, or both are obtained, the gestational age and the EDD should be determined, discussed with the patient, and documented clearly in the medical record.
The American College of Obstetricians and Gynecologists, the American Institute of Ultrasound in Medicine, and the Society for Maternal—Fetal Medicine recognize the advantages of a single dating paradigm being used within and between institutions that provide obstetric care. Table 1 provides guidelines for estimating the due date based on ultrasonography and the LMP in pregnancy, and provides single-point cutoffs and ranges based on available evidence and expert opinion.
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