Prenatal Assessment of Gestational Age - Case Presentation
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Prenatal Assessment of Gestational Age - Case Presentation تقدير عمل الحمل، حالة سريرية. Faculty of Medicine of Syrian Private University كليّة الطّبّ البشريّ في الجامعة السّوريّة الخاصّة 20-12-2015
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Prenatal Assessment of Gestational Age - Case Presentation
- 1. Prenatal Assessment of Gestational Age - Case Presentation Nawras Al Halabi - NawrasAlHalabi.com Salam Sulayman - DrSalam@dr.com
- 2. Medical History • A woman is referred from the general practitioner for pregnancy dating. She had a positive pregnancy test 3 days ago after she realized that she had missed a period. • In the past she had a regular cycles bleeding for 5 days every 28 days. However she had been taking the combined oral contraceptive pill (COCP) for the last 6 years and stopped only 10 weeks ago. • She had a withdrawal bleed at the end of the last packet, followed by an apparently normal period 5 weeks later. She has had no other irregular bleeding or any abdominal pain. She has had regular intercourse throughout the time since she stopped her COCP and is pleased now to be pregnant.
- 3. Investigations • Transvaginal Ultrasound findings are shown:
- 4. Questions • How can pregnancies be dated and what is the approximate gestational age for this pregnancy? • What further investigations would you like to do to confirm this? • Why is correct early pregnancy dating important?
- 5. Assessment of gestational age
- 6. Importance of reliable pregnancy dating Important for the mother, who wants to know when to expect the birth of her baby. This information related to gestational is invaluable!
- 7. Importance of reliable pregnancy dating • Important for Health care providers: Most obstetrical management decisions are strongly influenced by consideration of fetal age which closely correlates with fetal development
- 8. Importance of reliable pregnancy dating Appropriate timing of gestation age-related testing Avoid iatrogenic newborn prematurity Decisions regarding delivery timing Decisions regarding treatment of PTL or PPROM Determine when to initiate post term fetal surveillance.
- 9. Length of pregnancies Hamster 16-23 Lion 108 Human 280 (40 weeks) Horse 330–342 Whale (sperm) 480–590 Elephant (African) 645
- 12. Methods – Naegele's rule • Most common method of pregnancy dating. • Using the date of the last menstrual period (LMP) To calculate the Estimated Date of Delivery ("due date" or EDD). EDD = LMP – 3 months + 7 days.
- 13. Methods – Naegele's rule Examples: LMP = February 20 EDD = November 27
- 14. Methods – Naegele's rule Example: LMP = May 28 EDD = March 4
- 15. Methods – Naegele's rule Inaccuracy occurs because: Many women do not have regular 28-day cycles or conceive on day 14. Many others are not certain of the date of their last period. Early pregnancy bleeding or the presence of light bleeding. Oral Contraceptive Pills (OCP). Breastfeeding. incorrect assumption of the date of ovulation
- 18. Physical examination Often described in terms of fruit! The uterus remains a pelvic organ until approximately 12 weeks of gestation It becomes Sufficiently large to palpate abdominally just above the symphysis pubis. Methods - Uterine size
- 20. Methods - Uterine size At 16 weeks, the uterine fundus is palpable Midway between the Symphysis Pubis and Umbilicus at 20 weeks it is palpable at the level of the Umbilicus At 36 weeks it is palpable at the level of the Xiphoid process At 40 weeks it is decline away from the Xiphoid process
- 21. 36 weeks 32 weeks 26 weeks 20 weeks 16 weeks 12 weeks 36 weeks 40 weeks
- 22. Leiomyoma Obesity Uterine malposition Multiple gestation. What interferes with accurate assessment Other factors affecting uterine size or the ability to palpate the uterus.
- 24. Methods - Sonographic assessment • Ultrasound estimation of EDD in the first half of pregnancy is superior to dating based on the last menstrual period or physical examination. 1. Mongelli M, Wilcox M, Gardosi J. Estimating the date of confinement: ultrasonographic biometry versus certain menstrual dates. Am J Obstet Gynecol 1996; 174:278. 2. Neilson JP. Ultrasound for fetal assessment in early pregnancy. Cochrane Database Syst Rev 2000; :CD000182. 3. Yang H, Kramer MS, Platt RW, et al. How does early ultrasound scan estimation of gestational age lead to higher rates of preterm birth? Am J Obstet Gynecol 2002; 186:433. One study of 34,249 singleton pregnancies reported that delivery occurred within seven days of the EDD more often when sonography alone1. A systematic review found reduced rates of induction of labor for postterm pregnancy2. A study of 44,623 women found that sonographic dating resulted in a small downward estimation of gestational age more often than an upward estimation
- 25. Methods - Sonographic assessment1 • 1 dayIVF • 3 daysOvulation • 3 daysIUI • 2 weeks 1st trimester • 4 weeks 2nd trimester • 6 weeks3rd trimester Parameter Variability 2SD Parameter Variability 2SD 1. Callen PW. Ultrasonography In obstetrics and gynecology. 5th ed. Sauders Elsevier; 2008;p. 3-25.
- 26. Methods - Sonographic assessment • Menstrual cycles are irregular. • Last menstrual period is unknown. • Patients who conceive while using hormonal contraception. • Uterine size estimated on physical examination differs from that predicted by menstrual dating. During 1st trimester: Typically obtained by transvaginal ultrasound examination
- 27. Methods - Sonographic assessment 1st trimester Gestational sac It is usually visible at 4.5 to 5 weeks of gestation. It is the first sonographic sign of an intrauterine pregnancy Double decidual sign appearing at 5.5 to 6 weeks
- 28. Methods - Sonographic assessment 1st trimester Gestational sac • The cursors should be placed on the sac itself and should not include the echogenic region surrounding the gestational sac.
- 29. Methods - Sonographic assessment 1st trimester Gestational sac • A size of 2 to 3 mm is the smallest size that can be clearly visualized within the uterine cavity = approximately 4 weeks and 1 to 3 days. • Mean Sac Diameter (MSD): derived by calculating the mean of the three orthogonal sac diameter measurements. 30 sac size (mm) Gestational age (days)
- 30. GS Week 4 Week 5 Week 6
- 31. Methods - Sonographic assessment 1st trimester Yolk sac • The first anatomic structure to appear within the gestational sac. • Provides confirmation of an intrauterine pregnancy. • Noted initially at the beginning of the 5th week of gestation (MSD approximately 5 mm); Appear when MSD approaches 8 mm. • Abnormal gestation are MSD of 8 mm or greater with an absent yolk sac.
- 33. Methods - Sonographic assessment 1st trimester Yolk sac • The yolk sac continues to grow to a maximum diameter of approximately 6 mm by 10 weeks of gestation. • The yolk sac migrates to the periphery of the chorionic cavity, and becomes undetectable sonographically by the end of the first trimester. The embryonic disc becomes visible at 1 to 2 mm in length gestational age of 5 to 6 weeks.
- 34. Crown rump length (CRL) • Is the standard biometric measurement of the embryo in the first trimester (age up to 14 weeks). • Is the longest straight-line measurement of the embryo measured from the outer margin of the cephalic pole to the rump. Methods - Sonographic assessment 1st trimester
- 35. Methods - Sonographic assessment 1st trimester Crown rump length (CRL): • Standard practice for determining gestational age is to take the mean of three CRL measurements. • Accuracy: • 7-10 weeks; ±3 days. • 10-14 weeks; ±5 days. • 15 weeks; ± 8.4 days. 1. Ohuma EO, Papageorghiou AT, Villar J, Altman DG (2013). "Estimation of gestational age in early pregnancy from crown-rump length when gestational age range is truncated: the case study of the INTERGROWTH-21st Project". BMC Med Res Methodol 13: 151. doi:10.1186/1471-2288-13-151. PMC 4029763. PMID 24314232 1
- 37. 12w16.7mm; 8w 1d
- 38. CRL < 25 mm 42 CRL (mm) GA (days) 1. Goldstein SR, Wolfson R. Endovaginal ultrasonographic measurement of early embryonic size as a means of assessing gestational age. J Ultrasound Med 1994; 13:27. 2. Ohuma EO, Papageorghiou AT, Villar J, Altman DG (2013). "Estimation of gestational age in early pregnancy from crown-rump length when gestational age range is truncated: the case study of the INTERGROWTH-21st Project". BMC Med Res Methodol 13: 151. doi:10.1186/1471-2288-13-151. PMC 4029763. PMID 24314232 1 2
- 39. A: Gestational sac (GS) B: Crown rump length (CRL) of embryo C: Amniotic sac; D: Yolk sac
- 40. Methods - Sonographic assessment 1st trimester Cardiac activity • Detection of cardiac activity establishes a gestational age of 5.5 to 6 weeks.
- 41. 5w
- 42. 6w, 7w
- 44. Methods - Sonographic assessment 2st and 3rd trimester During 2st and 3rd trimester: Typically obtained by transabdominal ultrasound examination Biparietal diameter (BPD) Head circumference (HC) Abdominal circumference (AC) Femur length (FL) Standard biometric parameters 2st and 3rd trimester
- 45. Methods - Sonographic assessment 2st and 3rd trimester Biparietal diameter (BPD) • The best studied biometric parameter • Accuracy: • 14-20 weeks; ±7 days • Mid-late 3rd trimester, = ±(3-4) weeks. • BPD is measured on a plane of section that in tersects both the third ventricle and thalami.
- 49. Methods - Sonographic assessment 2st and 3rd trimester • The fetal cranium may not always display a traditional shape. • Cephalic index (CI): the ratio of BPD / occipitofrontal diameter (OFD) × 100. • The standard CI range for normal shaped craniums approximates one standard deviation from the mean (>74 or <83). • ⇨ CI measurement approaches the outer limits of the normal range, the use of the BPD for estimation of gestational age is not accurate.
- 51. Methods - Sonographic assessment 2st and 3rd trimester • Accuracy: • Prior to 20 weeks; ±1 week. • Late third trimester; ±(3-4) weeks. • The correct plane for the image passes through the thalami and third ventricle. Head circumference (HC) • Provides a good estimate of gestational age on routine sonograms. • Also is useful in the clinical setting of growth disorders.
- 54. Methods - Sonographic assessment 2st and 3rd trimester Abdominal Circumference (AC) • Appears to have a slightly lower ability to predict gestational age early in the second trimester than the BPD, HC, and FL. • Some of the variability may be due to error in ultrasound technique, along with natural biologic variations. • Accuracy: • Second trimester; ±2 weeks. • Late third trimester; ±(3-4) weeks.
- 55. Methods - Sonographic assessment 2st and 3rd trimester Abdominal Circumference (AC) • AC is often used for estimations of fetal weight and interval growth evaluations rather than gestational age assessment. • The image is taken at the level of the largest diameter of the fetal liver, denoted by the point of union of the right and left portal veins, which has a "hockey stick" appearance. • The correct plane can be confirmed by visualizing the umbilical segment of the left portal vein in its shortest length
- 58. Methods - Sonographic assessment 2st and 3rd trimester Femur length (FL) • Can be measured as early as 10 weeks gestational age because of its size and echogenicity. • Accuracy: • Prior to 20 weeks; ±1 week; 3rd trimester; ±(2.1-3.5) weeks. • Average femur length appears to vary slightly among ethnic groups.
- 59. Methods - Sonographic assessment 2st and 3rd trimester Femur length (FL) • Short femurs may be a normal finding or a marker of aneuploidy (trisomy 21). • Severely shortened (<5th percentile) or abnormal appearing femurs in the second trimester suggest a skeletal dysplasia or early onset fetal growth restriction
- 62. Other biometric parameters Interorbital diameters Transverse cerebellar diameter Clavicle length Foot length Length of long bones of the extremities
- 63. Other biometric parameters Interorbital diameters
- 64. Other biometric parameters Transverse cerebellar diameter
- 65. Other biometric parameters Clavicle length
- 66. Other biometric parameters Foot length
- 67. Other biometric parameters Length of long bones of the extremities
- 68. Use of multiple markers • Various fetal body ratio indexes: • Define how these measurements correlate in an average fetus. • Determine if a parameter is potentially abnormal. HC/AC BPD/FL FL/AC
- 69. Use of multiple markers • After a careful assessment, it is usually appropriate to omit a single discordant parameter from the gestational age calculation. • Additional measurements may be useful when there are biometric discrepancies. • Ex: The transverse cerebellar diameter (in millimeters) correlates with gestational age up to 22 weeks of gestation.
- 70. Signs of fetal maturity When an early ultrasound examination has not been performed or menstrual dates are unknown or uncertain. There are several signs suggestive of fetal maturity that can be observed sonographically and correlated with gestational age.
- 71. Signs of fetal maturity • Ex: the femoral epiphyseal and proximal tibial ossification centers are well visualized by 32 and 35 weeks gestational age, respectively • The proximal humeral epiphysis also appears in the late third trimester and correlates with fetal lung maturity and gestational age
- 72. Combined oral contraceptive pill (COCP) • Often referred to as the birth control pill. • Combination of an estrogen (estradiol) and progesterone (progestin). • When taken by mouth every day, these pills inhibit female fertility. • The most side effect is withdrawal bleeding.
- 74. Medical History • A woman is referred from the general practitioner for pregnancy dating. She had a positive pregnancy test 3 days ago after she realized that she had missed a period. • In the past she had a regular cycles bleeding for 5 days every 28 days. However she had been taking the combined oral contraceptive pill (COCP) for the last 6 years and stopped only 10 weeks ago. • She had a withdrawal bleed at the end of the last packet, followed by an apparently normal period 5 weeks later. She has had no other irregular bleeding or any abdominal pain. She has had regular intercourse throughout the time since she stopped her COCP and is pleased now to be pregnant.
- 75. Investigations • Transvaginal Ultrasound findings are shown:
- 76. Questions How can pregnancies be dated and what is the approximate gestational age for this pregnancy?
- 79. The uterus remains a pelvic organ until approximately 12 weeks of gestation It becomes Sufficiently large to palpate abdominally just above the symphysis pubis. Clinical Assessment Uterine Size 12 weeks
- 80. Questions What further investigations would you like to do to confirm this?
- 81. Sonographic Assessment First sonographic sign of an intrauterine pregnancy Visible at 4.5 to 5 weeks Gestational Sac
- 82. Sonographic Assessment Yolk Sac The first anatomic structure to appear within the gestational sac. Provides confirmation of an intrauterine pregnancy. Noted initially at the beginning of the 5th week of gestation The embryonic disc becomes visible at 1 to 2 mm in length gestational age of 5 to 6 weeks.
- 83. Sonographic Assessment Cardiac activity Detection of cardiac activity establishes a gestational age of 5.5 to 6 weeks.
- 84. First trimester screening FIRST TRIMESTER COMBINED TEST Maternal serum beta human chorionic gonadotropin (beta-hCG) Maternal serum pregnancy-associated plasma protein-A (PAPP-A) Ultrasound measurement of nuchal translucency (NT) To detect Down Syndrome and Trisomy 18
- 85. Questions Why is correct early pregnancy dating important?
- 86. Importance of reliable pregnancy dating Important for the mother, who wants to know when to expect the birth of her baby. This information related to gestational is invaluable!
- 87. Importance of reliable pregnancy dating • Important for Health care providers: Most obstetrical management decisions are strongly influenced by consideration of fetal age which closely correlates with fetal development
- 88. Importance of reliable pregnancy dating Appropriate timing of gestation age-related testing Avoid iatrogenic newborn prematurity Decisions regarding delivery timing Decisions regarding treatment of PTL or PPROM Determine when to initiate post term fetal surveillance.
- 89. Thank you!
Editor's Notes
- z
- (serum screening, assessment of maturity, treatment of PTL, PPROM, induction of labor for postdate pregnancies…)
- (serum screening, assessment of maturity, treatment of PTL, PPROM, induction of labor for postdate pregnancies…)
- (serum screening, assessment of maturity, treatment of PTL, PPROM, induction of labor for postdate pregnancies…)
- (serum screening, assessment of maturity, treatment of PTL, PPROM, induction of labor for postdate pregnancies…)
- using the date of the last menstrual period (LMP) to calculate the estimated date of delivery ("due date" or EDD), and physical examination The clinical assessment of gestational age or duration of pregnancy reflects the "menstrual age." In contrast, embryologists always date developmental events from the time of fertilization, which is the "embryonic age. EDD is calculated by counting back three months from the last menstrual period and adding seven days.
- This method assumes the patient has a 28-day menstrual cycle with fertilization occurring on day 14. using the date of the last menstrual period (LMP) to calculate the estimated date of delivery ("due date" or EDD), and physical examination The clinical assessment of gestational age or duration of pregnancy reflects the "menstrual age." In contrast, embryologists always date developmental events from the time of fertilization, which is the "embryonic age.
- This method assumes the patient has a 28-day menstrual cycle with fertilization occurring on day 14. using the date of the last menstrual period (LMP) to calculate the estimated date of delivery ("due date" or EDD), and physical examination The clinical assessment of gestational age or duration of pregnancy reflects the "menstrual age." In contrast, embryologists always date developmental events from the time of fertilization, which is the "embryonic age.
- On physical examination, the pregnant uterus is soft and globular
- On physical examination, the pregnant uterus is soft and globular
- 3*(eg, retroverted uterus).
- 3*(eg, retroverted uterus).
- Ultrasound is commonly used to estimate gestational age and thereby calculate the expected date of delivery (EDD) *Several studies have demonstrated that: 1: with both certain menstrual dates and ultrasonographic biometry 2: among women who underwent ultrasound examination before 24 weeks concluded that routine ultrasound in early pregnancy enabled better gestational age assessment 3: who had both a normal last menstrual period and ultrasound examination before 20 weeks of gestation
- Ultrasound is commonly used to estimate gestational age and thereby calculate the expected date of delivery (EDD) *Several studies have demonstrated that: 1: with both certain menstrual dates and ultrasonographic biometry 2: among women who underwent ultrasound examination before 24 weeks concluded that routine ultrasound in early pregnancy enabled better gestational age assessment 3: who had both a normal last menstrual period and ultrasound examination before 20 weeks of gestation
- Using transvaginal sonography
- Using transvaginal sonography
- Using transvaginal sonography I A size of 2 to 3 mm is the smallest size that can be clearly visualized within the uterine cavity and correlates with a gestational age of approximately four weeks and one to three days [10-12]. As the gestation progresses Gestational sac measurement is less accurate later in pregnancy, when the embryonic or fetal pole can be identified [19]; therefore, it is used for dating only very early pregnancies. The crown rump length is a more accurate indicator of gestational age than mean gestational sac diameter so once the embryonic pole is evident and crown rump length should be used to determine an EDD. However, this mean sac diameter may be recorded when an embryo is not identified.
- Using transvaginal sonography I A size of 2 to 3 mm is the smallest size that can be clearly visualized within the uterine cavity and correlates with a gestational age of approximately four weeks and one to three days [10-12]. As the gestation progresses Gestational sac measurement is less accurate later in pregnancy, when the embryonic or fetal pole can be identified [19]; therefore, it is used for dating only very early pregnancies. The crown rump length is a more accurate indicator of gestational age than mean gestational sac diameter so once the embryonic pole is evident and crown rump length should be used to determine an EDD. However, this mean sac diameter may be recorded when an embryo is not identified.
- The yolk sac is spherical with a sonolucent center and echogenic periphery. However, since there is patient and scanning variability, this sac size should not be taken as an absolute threshold for diagnosis of an abnormal pregnancy. Either correlation with hCG and/or sonographic follow-up should be obtained if an initial evaluation of pregnancy shows an 8 mm empty sac without a yolk sac.
- The yolk sac is spherical with a sonolucent center and echogenic periphery. However, since there is patient and scanning variability, this sac size should not be taken as an absolute threshold for diagnosis of an abnormal pregnancy. Either correlation with hCG and/or sonographic follow-up should be obtained if an initial evaluation of pregnancy shows an 8 mm empty sac without a yolk sac. As discussed above, the gestational sac and yolk sac lose their accuracy for gestational age assessment as the pregnancy advances Direct measurement of the crown rump length of the embryo provides the most accurate estimate of gestational age once the embryonic pole is evident and should be used to determine an EDD
- A length of at least 5 mm routinely allows visualization of the embryo, but some embryos as small as 2 to 3 mm can be seen.
- This variation has been attributed to normal biological differences in embryologic development and variations in anatomical positioning of the fetal head and torso Both first trimester growth delay and growth acceleration are active areas of investigation **picture** Diagram showing crown-rump length bygestational age. The blue line is the mean and the green area delimits the 3rd versus the 97thpercentile.[1]
- Image of an early gestational sac demonstrating the early embryo. Calipers are placed at both ends of the embryo measuring the longest length from the "crown to the rump" giving the crownrump length. This measurement is used for dating the pregnancy. Surrounding the embryo is the developing amnion as shown by the hyperechoic circular line. Courtesy of Thomas Shipp, MD.
- This variation has been attributed to normal biological differences in embryologic development and variations in anatomical positioning of the fetal head and torso Both first trimester growth delay and growth acceleration are active areas of investigation
- Last parameters were obtained by transvaginal ultrasound
- Last parameters were obtained by transvaginal ultrasound
- the calvarium should appear smooth and symmetrical in the plane of section The appropriate image can be obtained by positioning the abdominal transducer perpendicular to the fetal parietal bones The cursors are then placed on the outer edge of the proximal skull and the inner edge of the distal skull; this length represents the BP
- ****particularly with breech presentations, oligohydramnios, premature rupture of the membranes, and neural tube abnormalities. Head compression or distortion from these conditions may result in an abnormal cranial conformation (eg, dolichocephaly) that lowers test performance of the BPD for gestational age estimation [19,59,60]. In these cases, the cephalic index should be measured. in these cases, head circumference (HC) (discussed below) is recommended for cranial assessment because it provides a good estimate of gestational age despite the fetus' irregular cranial structure
- However, additional intracerebral landmarks that must be visualized to obtain the appropriate measurement include the cavum septum pellucidum anteriorly and the tentorial hiatus posteriorly The standard view should not include the cerebellum or the cerebral ventricles. The calvarium should always appear symmetrical in the image. HC measurements are obtained by placing the cursors on the outer margins of the calvarium bilaterally [19], in contrast to BPD measurements, which extend from the inner calvarium on one side to the outer calvarium on the other side. By using the computerized ellipse function, the ultrasound machine will assist in the approximation of the outer perimeter of the calvarium. It is important to avoid measuring the outer margin of the skin overlying the scalp, since doing so will falsely increase the HC.
- Axial view of the fetal head at the level used to measure the biparietal diameter and head circumference. The cavum septum pellucidum (large arrow) and slit-like third ventricle (short arrow) are indicated. Courtesy of Andrew P MacKenzie, MD
- However, the AC can be a valuable additional measure for dating during the second trimester, especially in fetuses with cranial or limb abnormalities This plane was chosen because the size of the liver correlates well with overall fetal growth ]. Two additional guidelines for correct measurement are (1) positioning the transducer perpendicularly to the fetal abdominal wall and (2) visualizing the symmetrical appearance of the lower ribs [19]. The fetal stomach is typically visualized on the AC view. The measurement is taken by placing four calipers around the abdomen on the skin edge, not the rib cage (figure 6). This will improve test performance while reducing the risk of underestimation of the AC [19]. The ultrasound machine will approximate the abdominal circumference. Another method is to use the electronic ellipse function on the ultrasound machine.
- **** The study of Prof Hammami; Syrian FL taller than Western. Even though FL is a simple "one-dimensional" image, errors in measurement often occur [72-74]. The transducer should be aligned along the long axis of the femoral bone
- **** The study of Prof Hammami; Syrian FL taller than Western. Even though FL is a simple "one-dimensional" image, errors in measurement often occur [72-74]. The transducer should be aligned along the long axis of the femoral bone
- The estimation of gestational age based on one parameter may be significantly different from that calculated from the others A thorough evaluation is warranted to determine the etiology of the abnormal measurement As an example, there may be a fetal abnormality such as hydrocephalus distorting the HC or BPD. Human error and normal variation in fetal size can result in over- or under-estimation of gestational age. Regression equations using the four standard biometric parameters minimize, but do not eliminate, these problems and yield the best estimation.
- The estimation of gestational age based on one parameter may be significantly different from that calculated from the others A thorough evaluation is warranted to determine the etiology of the abnormal measurement As an example, there may be a fetal abnormality such as hydrocephalus distorting the HC or BPD. Human error and normal variation in fetal size can result in over- or under-estimation of gestational age. Regression equations using the four standard biometric parameters minimize, but do not eliminate, these problems and yield the best estimation.
- However, as with all parameters discussed, the accuracy of additional measurements is age-dependent with significant variability in late pregnancy. A potential source of bias is when the ultrasound screen displays the calculated gestational age next to each biometric measurement. The sonographer may adjust the position of the cursors to fit the expected fetal age as opposed to the actual anatomic reference points
- Identification of such landmarks suggests the fetus has most likely attained these milestones in the third trimester. Identification of such landmarks suggests the fetus has most likely attained these milestones in the third trimester
- Identification of such landmarks suggests the fetus has most likely attained these milestones in the third trimester. Identification of such landmarks suggests the fetus has most likely attained these milestones in the third trimester
- Identification of such landmarks suggests the fetus has most likely attained these milestones in the third trimester. Identification of such landmarks suggests the fetus has most likely attained these milestones in the third trimester
- A single late examination cannot reliably distinguish between a pregnancy that is misdated and younger than expected Clinicians should be particularly cautious when changing the EDD based upon measurements obtained from an ultrasound examination performed late in pregnancy. pregnancy that is complicated by fetal growth restriction. Late pregnancy ultrasound measurements should never be used to change an EDD established by an examination performed earlier in pregnancy. After 28 weeks of gestation, it is inappropriate to rely solely on a single set of the usual biometric parameters for fetal dating When an EDD is revised because of smaller than expected size of the fetus on a second ultrasound examination, we suggest a follow-up ultrasound to evaluate fetal growth over time and make sure this finding was not due to early growth restriction.
- ****It is usually visible at 4.5 to 5 weeks of gestation. It is the first sonographic sign of an intrauterine pregnancy
- *****The first anatomic structure to appear within the gestational sac. Provides confirmation of an intrauterine pregnancy. Noted initially at the beginning of the 5th week of gestation
- 2*although the value of this test is questionable in women with normal blood pressure
- 2*although the value of this test is questionable in women with normal blood pressure
- (serum screening, assessment of maturity, treatment of PTL, PPROM, induction of labor for postdate pregnancies…)
- (serum screening, assessment of maturity, treatment of PTL, PPROM, induction of labor for postdate pregnancies…)
- 2*although the value of this test is questionable in women with normal blood pressure