Ultrasonographic assessment of gestational age with the distal femoral and proximal tibial ossification centers in the third trimester

Neonatal Thyrotoxicosis in Infants of Mothers with Graves' Disease Treated for Radioiodine-Induced Hypothyroidism: A Literature Review

Fetal and neonatal thyrotoxicosis occurs in up to 5% of pregnancies in mothers with Graves' disease (GD). This condition is caused by stimulating antibodies against the thyrotropin receptor (TRAbs) that cross the placenta and may stimulate the fetal thyroid, typically in the second half of pregnancy. GD is often treated with radioiodine, resulting in hypothyroidism in most patients, but TRAbs can persist for several years. Even if a pregnant mother is hypothyroid after radioiodine therapy or surgery, her TRAbs can still, although rarely, induce fetal hyperthyroidism. In this review, we first present two cases of neonatal hyperthyroidism in mothers with GD who became hypothyroid after prior radioiodine therapy, identified through a 10-year analysis of the National Perinatal System in Slovenia. Based on these cases, we provide an overview of existing data on this rare clinical condition in neonates. We also discuss the underlying mechanisms and clinical outcomes based on currently available data. In conclusion, our review highlights the importance of careful monitoring during pregnancy in all women with GD, even in those well managed after radioiodine therapy or surgery.

Fetal Hyperthyroidism with Maternal Hypothyroidism: Two Cases of Intrauterine Therapy

Fetal hyperthyroidism can occur secondary to maternal autoimmune hyperthyroidism. The thyroid-stimulating hormone receptor antibody (TRAb) transferred from the mother to the fetus stimulates the fetal thyroid and causes fetal thyrotoxicosis. Fetuses with this condition are difficult to detect, especially after maternal Graves disease therapy. Here, we present two cases of fetal hyperthyroidism with maternal hypothyroidism and review the assessment and intrauterine therapy for fetal hyperthyroidism. Both women were referred at 22+ and 23+ weeks of gestation with abnormal ultrasound findings, including fetal heart enlargement, pericardial effusion, and fetal tachycardia. Both women had a history of Graves disease while in a state of hypothyroidism with a high titer of TRAb. A sonographic examination showed a diffusely enlarged fetal thyroid with abundant blood flow. Invasive prenatal testing revealed no significant chromosomal aberration. Low fetal serum TSH and high TRAb levels were detected in the cord blood. Fetal hyperthyroidism was considered, and maternal oral methimazole (MMI) was administered as intrauterine therapy, with the slowing of fetal tachycardia, a reduction in fetal heart enlargement, and thyroid hyperemia. During therapy, maternal thyroid function was monitored, and the dosage of maternal levothyroxine was adjusted accordingly. Both women delivered spontaneously at 36+ weeks of gestation, and neonatal hyperthyroidism was confirmed in both newborns. After methimazole and propranolol drug treatment with levothyroxine for 8 and 12 months, both babies became euthyroid with normal growth and development.

Femur development in fetal growth restriction as observed on prenatal magnetic resonance imaging

OBJECTIVE

To investigate human femur development in fetal growth restriction (FGR) by analyzing femur morphometrics and distal epimetaphyseal features on prenatal magnetic resonance imaging (MRI).

METHODS

This was a retrospective study of 111 fetuses (mean gestational age (GA), 27 + 2 weeks (range, 19-35 weeks)) with FGR associated with placental insufficiency without other major abnormalities and 111 GA-matched normal controls. On 1.5-Tesla echoplanar MRI, femur morphometrics, including diaphyseal length, epiphyseal length and epiphyseal width, were assessed. Using a previously reported grading system, epimetaphyseal features, including cartilaginous epiphyseal shape, metaphyseal shape and epiphyseal ossification, were analyzed qualitatively. To compare FGR cases and controls, the paired t-test was used to assess morphometrics, generalized estimating equations were used for epimetaphyseal features and time-to-event analysis was used to assess the visibility of epiphyseal ossification.

RESULTS

There were significant differences in femur morphometrics between FGR cases and controls (all parameters, P < 0.001), with bone shortening observed in FGR. No significant differences were found in the distribution of epimetaphyseal features between FGR cases and controls (epiphyseal shape, P = 0.341; metaphyseal shape, P = 0.782; epiphyseal ossification, P = 0.85). Epiphyseal ossification was visible at a median of 33.6 weeks in FGR cases and at 32.1 weeks in controls (P = 0.008).

CONCLUSIONS

On prenatal MRI, cases with FGR associated with placental insufficiency exhibit diaphyseal and epiphyseal shortening of the femur. However, FGR cases and normal controls share similarly graded distal epimetaphyseal features. Consequently, these features may not be appropriate MRI characteristics for the identification of FGR. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Modified Serum ALP Values and Timing of Apparition of Knee Epiphyseal Ossification Centers in Preterm Infants with Cholestasis and Risk of Concomitant Metabolic Bone Disease of Prematurity

The usefulness of serum alkaline phosphatase (ALP) and phosphorous in screening and monitoring of metabolic bone disease of prematurity (MBDP) still has some limitations, especially in preterm infants with concomitant conditions such as cholestasis. We aimed to assess a modification of serum ALP (M-ALP) as a biomarker for MBDP in preterm infants, and the use of ultrasound monitoring for the apparition of knee ossification centers as marker of bone mineralization. Biochemical and clinical registers were taken from 94 preterm newborns <32 weeks. A significant correlation existed between serum ALP and direct bilirubin (DB), expressed by the regression equation: M-ALP (IU/L) = 302.1 + 96.9 (DB (mg/dL)). The ratio ALP/M-ALP > 1 was demonstrated to be more specific (87.5%) in the diagnosis of MBDP than the cut-off value of serum ALP > 500 IU/L (62.5%). ALP/M-ALP > 1 showed 100% sensitivity and specificity for the diagnosis of MBDP, and a good correlation with specific bone ALP (B-ALP). Patients with the knee nucleus by post-menstrual week 37 had lower B-ALP compared to patients with no nucleus, and no patients with MBDP presented the nucleus by the 40th week. In the absence of reliable specific B-ALP, reinterpreting serum ALP values by M-ALP plus monitoring of knee ossification centers contribute to better management of MBDP in preterm infants with cholestasis.

Guideline No. 388-Determination of Gestational Age by Ultrasound

OBJECTIVE

To assist clinicians in assigning gestational age based on ultrasound biometry.

OUTCOMES

To determine whether ultrasound dating provides more accurate gestational age assessment than menstrual dating with or without the use of ultrasound. To provide maternity health care providers and researchers with evidence-based guidelines for the assignment of gestational age. To determine which ultrasound biometric parameters are superior when gestational age is uncertain. To determine whether ultrasound gestational age assessment is cost effective.

EVIDENCE

Published literature was retrieved through searches of PubMed or MEDLINE and The Cochrane Library in 2013 using appropriate controlled vocabulary and key words (gestational age, ultrasound biometry, ultrasound dating). Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies written in English. There were no date restrictions. Searches were updated on a regular basis and incorporated in the guideline to July 31, 2013. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies.

VALUES

The quality of evidence in this document was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care (Table 1).

BENEFITS, HARMS, AND COSTS

Accurate assignment of gestational age may reduce post-dates labour induction and may improve obstetric care through allowing the optimal timing of necessary interventions and the avoidance of unnecessary ones. More accurate dating allows for optimal performance of prenatal screening tests for aneuploidy. A national algorithm for the assignment of gestational age may reduce practice variations across Canada for clinicians and researchers. Potential harms include the possible reassignment of dates when significant fetal pathology (such as fetal growth restriction or macrosomia) result in a discrepancy between ultrasound biometric and clinical gestational age. Such reassignment may lead to the omission of appropriate-or the performance of inappropriate-fetal interventions.

SUMMARY STATEMENTS

RECOMMENDATIONS.

Ultrasonographic assessment of fetal thyroid in Japan: thyroid circumference and distal femoral and proximal tibial ossification

PURPOSE

The present study established a nomogram of fetal thyroid circumference (FTC) and the appearance timing of fetal distal femoral and proximal tibial ossification to assess fetal thyroid function in Japan.

METHODS

Between April 2015 and July 2019, normal pregnant women at our hospital were recruited for the study. FTC was measured by the automatic ellipse outline and plotted against gestational age (GA). Fetal distal femoral and proximal tibial ossification measurements were obtained with standard electronic calipers from outer-to-outer margins (> 1 mm as the presence of ossification).

RESULTS

A total of 199 pregnant women were examined. FTC increased logarithmically to GA. A nomogram of FTC was expressed by a logarithmic formula: [Formula: see text]. The respective 5-95th percentiles of FTC at each GA were 20.2-36.2 mm at 22 weeks, 25.0-44.8 mm at 26 weeks, 29.2-52.3 mm at 30 weeks, and 32.9-59.0 mm at 34 weeks. The fetal distal femoral epiphysis was not visualized before 30 weeks, but was visualized in 100% of fetuses after 35 weeks of gestation. The fetal proximal tibial epiphysis was not visualized before 33 weeks, but was visualized in 73.7% of fetuses at 37 weeks of gestation.

CONCLUSION

We generated a GA-dependent FTC nomogram for Japanese fetuses. We also confirmed the appearance timing of fetal distal femoral and proximal tibial ossification to assess bone maturation. These assessments may be very useful for evaluating fetal thyroid function in Japan.

Three-dimensional growth of tibial shaft ossification in the human fetus: a digital-image and statistical analysis

PURPOSES

Tibial shaft ossification in terms of its size and growth may be criticalin describing both the fetal stage and maturity, and in identifying innate disorders. The present study was executed to quantitatively assess ossification of the tibial shaft, taking its morphometric linear, planar and volumetric parameters into account.

MATERIALS AND METHODS

With the use of methods of CT, digital-image analysis and statistics, the evolutionof tibial shaft ossification in 47 spontaneously aborted human fetuses at the age of 17-30 weeks was studied.

RESULTS

Without any male-female and right-left morphometric differences, the best fit growth dynamics fortibial shaft ossification was modelled by the following functions: y = 5.312 + 0.034 × (age)² ± 0.001 (R² = 0.89) for its length, y = - 2.855 + 0.307 × age ± 0.009 (R² = 0.96) for its proximal transverse diameter, y = - 0.758 + 0.153 × age ± 0.005 (R² = 0.88) for its middle transverse diameter, y = - 1.844 + 0.272 × age ± 0.09 (R² = 0.90) for its distal transverse diameter, y = - 40.263 + 0.258 × (age)² ± 0.007 (R² = 0.94) for its projection surface area, and y = - 287.996 + 1.186 × (age)² ± 0.037 (R² = 0.92) for its volume. The femoral-to-tibial ossification length ratio was 1.15 ± 0.1.

CONCLUSIONS

The size of tibial shaft ossification displays neither sex nor laterality differences. Tibial shaft ossification follows quadratic functions with respect to its length, projection surface area and volume, and linear functions with respect to its proximal, middle and distal transverse diameters. The obtained morphometric data of tibial shaft ossification are considered normative age-specific references of relevance in both the estimation of fetal ages and the ultrasound diagnostics of congenital defects.

Fetal Skeletal Size and Growth are Relevant Biometric Markers in Vitamin D Deficient Mothers: A North East India Prospective Cohort Study

CONTEXT

The neonatal skeletal outcomes due to maternal Vitamin D deficiency.

AIMS

The aim of this study is to assess the serum 25 hydroxy Vitamin D (25[OH]D) status in pregnant women and correlate with cord blood 25(OH)D levels, femur length at 34 weeks gestation, and neonatal anthropometry (birth weight, birth length, and head circumference).

SETTINGS AND DESIGN

This was prospective cohort study.

SUBJECTS AND METHODS

This study was carried out in 250 healthy primigravida between 18 and 40 years of age in the third trimester of gestation attending the Obstetrics and Gynaecology Department of Gauhati Medical College, Guwahati from December 2012 to December 2015. Dietary assessment of calcium and Vitamin D intake, sunlight exposure among the pregnant mothers and fetal femur length measurements were done. The neonates were followed up at birth for biometric assessment and the estimation of cord 25(OH)D.

STATISTICAL ANALYSIS USED

Chi-square test and Pearson correlation were carried out to see the association and correlation between different variables. Statistical significance was set at the 0.05 level.

RESULTS

We found low Vitamin D levels (60%) in the majority of pregnant mothers and newborns (62.4%). The mean Vitamin D levels were 17.51 ± 2.24 ng/ml and 14.51 ± 1.8 ng/ml among the low Vitamin D maternal subjects and their new born, respectively. There was a significant association of maternal Vitamin D levels with sun exposure, dietary intake of Vitamin D, serum calcium, serum alkaline phosphatase levels, and serum parathyroid hormone in subjects with low Vitamin D. Fetal femur length and birth length were significantly shorter in mothers with low Vitamin D (P < 0.01).

CONCLUSIONS

Maternal hypovitaminosis D was associated with adverse skeletal outcome in neonates.

Neonatal Thyrotoxicosis

Neonatal thyrotoxicosis (hyperthyroidism) is less prevalent than congenital hypothyroidism; however, it can lead to significant morbidity and mortality if not promptly recognized and adequately treated. Most cases are transient, secondary to maternal autoimmune hyperthyroidism (Graves disease [GD]). This article summarizes recommendations for screening and management of hyperthyroidism in both the fetal and neonatal periods, with a focus on neonatal thyrotoxicosis secondary to maternal GD. Early monitoring and treatment are crucial for optimizing short-term and long-term patient outcomes.

Quantitative anatomy of the primary ossification center of the femoral shaft in human fetuses

Purpose

Early clinical distinction of congenital defects in the femur is extremely important, as it determines the prognosis of the development of the lower limb. This study was performed to quantitatively examine the primary center of ossification in the femoral shaft with respect to its linear, planar, and volumetric parameters.

Materials and methods

Using methods of CT, digital-image analysis, and statistics, the size of the primary ossification center of the femoral shaft in 47 spontaneously aborted human fetuses aged 17–30 weeks was studied.

Results

With no sex and laterality differences, the best fit growth dynamics for femoral shaft ossification center was modelled by the following functions: y = 5.717 + 0.040 × (age)² ± 2.905 (R² = 0.86) for its length, y = −3.579 + 0.368 × age ± 0.529 (R² = 0.88) for its proximal transverse diameter, y = −1.105 + 0.187 × age ± 0.309 (R² = 0.84) for its middle transverse diameter, y = −2.321 + 0.323 × age ± 0.558 (R² = 0.83) for its distal transverse diameter, y = −50.306 + 0.308 × (age)² ± 18.289 (R² = 0.90) for its projection surface area, and y = −91.458 + 0.390 × (age)³ ± 92.146 (R² = 0.88) for its volume.

Conclusions

The size of the femoral shaft ossification center displays neither sex nor laterality differences. The ossification center in the femoral shaft follows quadratic functions with respect to its length and projection surface area, linear functions with respect to its proximal, middle, and distal transverse diameters, and a cubic function with respect to its volume. The obtained morphometric data of the femoral shaft ossification center are considered normative for respective prenatal weeks and may be of relevance in both the estimation of fetal ages and the ultrasound diagnostics of congenital defects.

Systematic radiographic evaluation of tibial hemimelia with orthopedic implications

Tibial hemimelia is a rare lower-extremity pre-axial longitudinal deficiency characterized by complete or partial absence of the tibia. The reported incidence is 1 in 1 million live births. In this pictorial essay, we define tibial hemimelia and describe associated conditions and principles of preoperative imaging assessment for a child with tibial hemimelia. We also indicate the imaging findings that might influence the choice of treatment, describe the most widely used classification systems, and briefly discuss current treatment approaches.

Fetal neonatal hyperthyroidism: diagnostic and therapeutic approachment

Fetal and neonatal hyperthyroidism may occur in mothers with Graves' disease. Fetal thyrotoxicosis manifestation is observed with the transition of TSH receptor stimulating antibodies to the fetus from the 17th-20th weeks of pregnancy and with the fetal TSH receptors becoming responsive after 20 weeks. The diagnosis is confirmed by fetal tachycardia, goiter and bone age advancement in pregnancy and maternal treatment is conducted in accordance. The probability of neonatal hyperthyroidism is high in the babies of mothers that have ongoing antithyroid requirement and higher antibody levels in the last months of pregnancy. Clinical manifestation may be delayed by 7-17 days because of the antithyroid drugs taken by the mother. Neonatal hyperthyroidism symptoms can be confused with sepsis and congenital viral infections. Herein, the diagnosis and therapeutic approach are reviewed in cases of fetal neonatal hyperthyroidism.

Détermination de l'âge gestationnel par échographie

OBJECTIF

Aider les cliniciens à attribuer un âge gestationnel en fonction des résultats de la biométrie échographique.

ISSUES

Déterminer si la datation par échographie offre une évaluation plus précise de l'âge gestationnel que la datation en fonction des dernières règles avec ou sans recours à l'échographie. Offrir, aux praticiens et aux chercheurs du domaine des soins de maternité, des lignes directrices factuelles en matière d'attribution de l'âge gestationnel. Identifier les paramètres biométriques échographiques qui sont de fiabilité supérieure lorsque l'âge gestationnel est incertain. Déterminer la rentabilité de l'évaluation de l'âge gestationnel par échographie. RéSULTATS: La littérature publiée a été récupérée par l'intermédiaire de recherches menées dans PubMed ou MEDLINE et The Cochrane Library en 2013 au moyen d'un vocabulaire contrôlé et de mots clés appropriés (p. ex. « gestational age », « ultrasound biometry » et « ultrasound dating »). Les résultats ont été restreints aux analyses systématiques, aux essais comparatifs randomisés / essais cliniques comparatifs et aux études observationnelles rédigés en anglais. Aucune restriction n'a été appliquée en matière de dates. Les recherches ont été mises à jour de façon régulière et intégrées à la directive clinique jusqu'au 31 juillet 2013. La littérature grise (non publiée) a été identifiée par l'intermédiaire de recherches menées dans les sites Web d'organismes s'intéressant à l'évaluation des technologies dans le domaine de la santé et d'organismes connexes, dans des collections de directives cliniques, dans des registres d'essais cliniques et auprès de sociétés de spécialité médicale nationales et internationales.

VALEURS

La qualité des résultats est évaluée au moyen des critères décrits dans le rapport du Groupe d'étude canadien sur les soins de santé préventifs (Tableau 1). AVANTAGES, DéSAVANTAGES ET COûTS: L'attribution précise d'un âge gestationnel pourrait réduire l'incidence du déclenchement mené en raison d'une grossesse prolongée et améliorer les soins obstétricaux en nous permettant de planifier la chronologie des interventions nécessaires de façon optimale et d'éviter les interventions inutiles. Une datation plus précise permet l'optimisation de la tenue de tests prénataux de dépistage de l'aneuploïdie. Un algorithme national d'attribution de l'âge gestationnel pourrait atténuer les variations pancanadiennes en matière de pratique pour les cliniciens et les chercheurs. Parmi les désavantages potentiels, on trouve la réattribution possible des dates lorsqu'une pathologie fœtale importante (comme le retard de croissance intra-utérin ou la macrosomie) donne lieu à une divergence entre les résultats de la biométrie échographique et l'âge gestationnel clinique. Une telle réattribution pourrait mener à l'omission d'interventions fœtales justifiées ou à la tenue d'interventions fœtales injustifiées. DéCLARATIONS SOMMAIRES: RECOMMANDATIONS.

Normal Fetal Growth Assessment: A Review of Literature and Current Practice

A review of literature and current practice of normal fetal growth assessment is presented. Ultrasonographic dating of pregnancy in the first, second, and third trimester is reviewed. Individual biometric parameters are examined, and the proper use of the fetal growth profile is explained. Use of this information is discussed as it pertains to the single pregnancy.

Ultrasound Assessment of the Skeletal Development of the Proximal Tibial, Proximal Femoral, and Distal Femoral Epiphyses in Premature and Mature Newborns

We evaluated postnatal skeletal development of the proximal femoral epiphysis, distal femoral epiphysis (DFE) and proximal tibial epiphysis (PTE) in 178 premature and mature newborns, between 25 and 47 wk of biological age, using high-resolution B-mode musculoskeletal ultrasound. Approximate age-related values were determined based on the ossification center size and epiphyseal cartilage thickness. The earliest onsets of visible mineralization were at 30 wk of maturity in the DFE, 31 wk in the PTE and 43 wk in the proximal femoral epiphysis. In preterm and term neonates, significant correlations were observed for transverse and longitudinal length of the DFE and PTE with biological age (R² = 0.35-0.50, p < 0.01). No significant age-dependent increases or decreases in cartilage thickness were seen between the ossification centers and cartilage surface in the DFE and PTE. High-resolution B-mode musculoskeletal ultrasound is an excellent tool for assessing skeletal development in premature and mature newborns.

Pränataldiagnostik bei fetaler Mikrozephalie

Diese Übersichtsarbeit behandelt die Mikrozephalie (MZ) aus der Perspektive der pränatalen Diagnostik. Eine MZ wird bei einem Kopfumfang unter der dritten Standardabweichung für das Gestationsalter vermutet. Diese Verdachtsdiagnose kann aus einem falschen Gestationsalter oder einer falsche Messung resultieren oder infolge einer Reihe häufiger Ätiologien wie offene Spina bifida, Enzephalozele, Holoprosenzephalie, Infektion, Aneuploidie, seltener auch Ursachen wie einer primären oder syndromalen MZ entstehen. Typische Ultraschallzeichen einer fetalen MZ sind die flache Stirn, der kleine Frontallappen, das reduzierte Gyrierungsmuster mit einem kurzen Balken, eine Pseudo-Kraniosynostose, ein dilatierter Subarachnoidalraum und oft eine Diskrepanz zwischen Kopf- und Bauchumfang. Mitunter kann eine schwere MZ schon in der Mitte der Schwangerschaft entdeckt werden, aber die meisten Formen fallen erst im III. Trimenon bzw. nach der Geburt auf. Die diagnostische Abklärung sollte auch das Angebot genetischer Untersuchungen einschließen, um monogen vererbte Formen mit hohem Wiederholungsrisiko z. B. bei autosomal-rezessiver Vererbung zu identifizieren. Die Arbeit diskutiert pränatalmedizinische und genetisch-diagnostische Abklärungsschritte bei fetaler MZ, die in Kombination mit den neuen genetischen Untersuchungstechniken hoffentlich in Zukunft zu einer höheren Aufklärungsrate führen werden.

Skeletal development on fetal magnetic resonance imaging

Prenatal magnetic resonance imaging (MRI) is being increasingly used, in addition to standard ultrasound, for the diagnosis of congenital diseases beyond the central nervous system. Previous studies have demonstrated that MRI may be useful for the in utero visualization of spinal dysraphism and for differentiating between isolated and complex skeletal disorders with associated abnormalities. More recently, attention has focused on the visualization of the human fetal skeleton for the delineation of normal and pathological development of skeletal structures. On 1.5 T, in particular, echoplanar imaging enables the delineation of various epimetaphyseal structures and morphometric measurements of the fetal long bones from 18 gestational weeks until term. This information gathered from prenatal MRI might be helpful in the diagnosis of focal bone abnormalities and generalized skeletal disorders, such as bone dysplasias. Further clinical research, along with the refinement of the newest techniques, will enable expansion of the preliminary findings and help in determining the impact of fetal magnetic resonance bone imaging in the routine clinical setting. This review summarizes the current data in the literature and the authors' clinical experience with the magnetic resonance visualization of the developing fetal skeleton and also comments on the potential future applications of this technique.

Use of fetal colon thickness for auxiliary term dating of pregnancy

OBJECTIVE

To verify whether fetal colon thickness can be used as a marker for estimating, independent of biometrics and fetal weight percentile, the gestational age (GA) of fetuses between 37 and 40 weeks.

METHODS

The study group was 1296 fetuses aged between 33 and 40 weeks. The correlation between GA and colon thickness was assessed by the Pearson correlation test. For term fetuses (≥ 37 weeks), comparisons among the mean colon thickness for different weight percentiles at each GA (in weeks) were made with an analysis of variance test.

RESULTS

A significant relationship was observed between GA and colon thickness (P < 0.001, r(2) = 0.6). For term fetuses, significant differences were observed among the mean colon thickness values for different weight percentiles at 38 and 39 weeks. Of the 157 term fetuses for which biometrics would have underestimated GA by 2 weeks or more, 126 (80.3%) had a colon thickness equal to, or greater than, 14 mm. This colon thickness was also observed in 52 (70.3%) of term fetuses weighing less than the 10th percentile (n = 74).

CONCLUSION

The present study suggested that colon thickness might be a good marker for 37 weeks of gestation, and might identify term fetuses for which biometrics has underestimated the GA.

Experience with intraamniotic thyroxine treatment in nonimmune fetal goitrous hypothyroidism in 12 cases

CONTEXT

Nonimmune fetal goitrous hypothyroidism is a rare condition that can induce obstetrical and/or neonatal complications and neurodevelopmental impairments such as those still seen in some patients with congenital hypothyroidism. Prenatal treatment to prevent these adverse outcomes is appealing, but experience is limited and the risk to benefit ratio controversial.

OBJECTIVE

The objective of the study was to evaluate the feasibility, safety, and effectiveness of intrauterine l-thyroxine treatment in a large cohort with nonimmune fetal goitrous hypothyroidism.

DESIGN

This was a retrospective study of 12 prenatally treated fetuses diagnosed between 1991 and 2005 in France.

METHODS

During pregnancy, goiter size and thyroid hormone levels were compared before and after prenatal treatment. At birth, clinical, laboratory, and ultrasound data were evaluated.

RESULTS

Prenatal treatment varied widely in terms of l-thyroxine dosage (200-800 microg/injection), number of injections (one to six), and frequency (every 1-4 wk). No adverse events were recorded. During pregnancy, thyroid size decreased in eight of nine cases and amniotic-fluid TSH levels decreased in the six investigated cases, returning to normal in four. However, at birth, all babies had hypothyroidism, indicating that intraamniotic TSH levels did not reliably reflect fetal thyroid function.

CONCLUSION

Our data confirm the feasibility and safety of intraamniotic l-thyroxine treatment for nonimmune fetal goitrous hypothyroidism. Although goiter size reduction is usually obtained, thyroid hormone status remains deficient at birth. Amniocentesis seems inadequate for monitoring fetal thyroid function. Further studies are needed to determine the optimal management of this disorder.

Use of ultrasound to distinguish between fetal hyperthyroidism and hypothyroidism on discovery of a goiter

OBJECTIVES

To determine whether sonography can be used to distinguish hyperthyroidism from hypothyroidism in pregnancies with fetal goiter.

METHODS

This was a retrospective study of 39 cases of fetal goiter. The majority of the mothers had Graves' disease. Fetuses were scanned for the existence of a hypertrophic thyroid gland (goiter) beginning at 22 gestational weeks. Once a goiter was diagnosed, different echographic features were analyzed and the effect of chosen treatment on fetal thyroid development was monitored.

RESULTS

On color Doppler, 68.8% of hypothyroid goiters had a peripheral vascular pattern vs. 20% in cases of fetal hyperthyroidism (P = 0.0574). No hypothyroid goiter presented central vascularization whereas half the hyperthyroid goiters did (P = 0.0013). Fetal tachycardia was a good indicator of hyperthyroidism (57.1% v.s 6.3%; P = 0.0055). Delayed bone maturation was seen in hypothyroid goiters (46.9% vs. 0%; P = 0.0307), while advanced bone maturity was specific to hyperthyroid goiters (85.7% vs. 0%; P < 0.0001). Lastly, an increase in fetal movement was observed in cases of fetal hypothyroidism (43.8% vs. 0%; P = 0.0364).

CONCLUSION

Based on the color Doppler pattern of goiter, fetal heart rate, bone maturation and fetal mobility, we established an ultrasound score to predict fetal thyroid function in cases of fetal goiter.

Nontraditional sonographic pearls in estimating gestational age

Accurate gestational dating is one of the most important assessments obstetrical providers make in pregnancy, given that all of the various management strategies are dependent on knowing where the patient is in gestation. In addition to traditional biometry, ancillary biometric and nonbiometric measurements can help narrow the biologic variability between fetuses. Moreover, one can employ these nontraditional measurements both in late gestation to assist in determining appropriate gestational age and fetal lung maturity, and in other specific clinical situations-such as oligohydramnios, in which compression of the fetal head and abdomen can lead to difficulty in obtaining an accurate biparietal diameter and abdominal circumference. This chapter focuses on nontraditional fetal ultrasound measurements, including the transverse cerebellar diameter, fetal foot length, ratios of biometric and nonbiometric measurements, epiphyseal ossification centers, amniotic fluid volume, placental grading, and other miscellaneous markers in the context of evaluating a fetus with possible intrauterine growth restriction.

Management of Graves' disease during pregnancy: the key role of fetal thyroid gland monitoring

BACKGROUND

Fetuses from mothers with Graves' disease may experience hypothyroidism or hyperthyroidism due to transplacental transfer of antithyroid drugs (ATD) or anti-TSH receptor antibodies, respectively. Little is known about the fetal consequences. Early diagnosis is essential to successful management. We investigated a new approach to the fetal diagnosis of thyroid dysfunction and validated the usefulness of fetal thyroid ultrasonograms.

METHODS

Seventy-two mothers with past or present Graves' disease and their fetuses were monitored monthly from 22 wk gestation. Fetal thyroid size and Doppler signals, and fetal bone maturation were determined on ultrasonograms, and thyroid function was evaluated at birth. Thyroid function and ATD dosage were monitored in the mothers.

RESULTS

The 31 fetuses whose mothers were anti-TSH receptor antibody negative and took no ATDs during late pregnancy had normal test results. Of the 41 other fetuses, 30 had normal test results at 32 wk, 29 were euthyroid at birth, and one had moderate hypothyroidism on cord blood tests. In the remaining 11 fetuses, goiter was visualized by ultrasonography at 32 wk, and fetal thyroid dysfunction was diagnosed and treated; there was one death, in a late referral, and 10 good outcomes with normal or slightly altered thyroid function at birth. The sensitivity and specificity of fetal thyroid ultrasound at 32 wk for the diagnosis of clinically relevant fetal thyroid dysfunction were 92 and 100%, respectively.

CONCLUSION

In pregnant women with past or current Graves' disease, ultrasonography of the fetal thyroid gland by an experienced ultrasonographer is an excellent diagnostic tool. This tool in conjunction with close teamwork among internists, endocrinologists, obstetricians, echographists, and pediatricians can ensure normal fetal thyroid function.

Sonographic identification and measurement of the epiphyseal ossification centers as markers of fetal gestational age

PURPOSE

This study was conducted to verify the predictive value of epiphyseal ossification center measurements in estimating gestational age.

METHODS

Women with singleton pregnancies of 30-40 weeks gestation (n = 377) were enrolled in this prospective study. The distal femoral, proximal tibial, and proximal humeral ossification centers were identified and measured. A nomogram of fetal bone development was created using the sum of the three diameters.

RESULTS

Gestational age correlated well with the diameters of the distal femoral and the proximal tibial epiphyseal ossification centers but even better with the sum of the three ossification centers. Positive predictive values of the fetus having gestational age of at least 37 weeks when the sum of the three centers was 7, 11, and 13 mm were 82%, 94%, and 100%, respectively. A nomogram was created using the sum of the ossification centers for 30-40 weeks' gestational age.

CONCLUSIONS

Ultrasonographic visualization of the epiphyses ossification centers may be a useful marker of fetal gestational age.

Diagnosis and management of intrauterine growth restriction

The growth-restricted fetus is a fetus who fails to reach his growth potential and is at risk for perinatal morbidity and mortality. When a fetus has an estimated weight below the 10th percentile, in the absence of congenital anomalies and in the presence of a normal amount of amniotic fluid, Doppler velocimetry gives the most important information to differentiate the truly growth-restricted fetus from the fetus that is constitutionally small but otherwise normal. One area of debate and research is whether Doppler velocimetry can help in timing the delivery of the growth-restricted fetus. Data appear to support the use of ductus venosus velocimetry in deciding when to deliver, but randomized data on this point are still lacking.

Sonographic biometry of the frontal lobe in normal and growth-restricted neonates

Assessing the impact of restricted intrauterine growth on neonatal frontal lobe (FL) dimensions is important. We aimed to create a sonographic nomogram of FL dimensions in neonates at different gestational ages (GA) and evaluate the impact of small head circumference (HC) on FL dimensions. We conducted sonographic biometry of the FL at birth. We included 218 newborn infants born at GA of 24-43 wk: appropriate for GA and normal HC (n = 178), and small for GA and small HC (n = 23). Infants with a 5-min Apgar score <7, severe congenital malformations, or chromosomal abnormalities were excluded. Through a coronal ultrasound scan via the anterior fontanelle at the level where the most lateral point of the left Sylvian fissure was best demonstrated, we drew a triangle connecting the most lateral point of the Sylvian fissure, the corpus callosum, and the subcalvarian point of the interhemispheric fissure. We measured the three sides of the triangle, Sylvian-fontanellar distance, Sylvian-callosal distance, and fontanellar-callosal distance, and calculated the frontal triangular area. All four FL dimensions increased significantly between 24 and 43 wk of gestation in both appropriate for GA-normal HC and small for GA-small HC neonates, and were strongly correlated with HC and birth weight. Regression lines of GA against Sylvian-fontanellar distance, Sylvian-callosal distance, fontanellar-callosal distance, and frontal triangular area in the appropriate for GA-normal HC group differed significantly from those of the small for GA-small HC group (p < 0.05). Male neonates had significantly larger Sylvian-fontanellar and Sylvian-callosal distances than females (p < 0.01 and p < 0.015, respectively). In conclusion, FL measures increased significantly between 24 and 43 wk of gestation, and were strongly correlated with HC. We speculate that a sonographically small fetal HC implies growth restriction of the fetal FL.

Sonography of Neural Tube Defects

High-resolution ultrasound has allowed increased definition and detailed study of the fetal brain. From 13 to 14 weeks gestation, congenital anomalies arising from or involving the central nervous system (CNS) can be visualized. Early detection and diagnosis of fetal neural tube defects (NTDs) are rapidly becoming an integral part of modern obstetric care. With the use of maternal serum alpha-fetoprotein (MSAFP) screening combined with high-resolution ultrasound, the potential exists to diagnose most NTDs before the 20th week of pregnancy.

Sonographic assessment of the distal femoral and proximal tibial ossification centers in the prediction of pulmonic maturity in normal women and women with diabetes

A noninvasive method for the assessment of fetal pulmonic maturity via the sonographic characterization of fetal distal femoral and proximal tibial epiphyseal ossification centers was evaluated. The study population included 82 patients in the third trimester of pregnancy, 47 of whom had uncomplicated gestations, while 35 had insulin-dependent diabetes. In uncomplicated pregnancies a distal femoral epiphysis measuring greater than or equal to 3 mm in the axial plane or the sonographic identification of a proximal tibial epiphysis of any dimension correlated with pulmonic maturity. The combination of a distal femoral epiphysis greater than or equal to 3 mm and the presence of a proximal tibial epiphysis was highly correlated with a lecithin/sphingomyelin ratio greater than or equal to 2:1 (sensitivity 100%, specificity 63%, negative predictive value 100%, and false-negative rate 0%). The Kappa value (K) for testing the agreement between ultrasound results and amniocentesis results was 0.39 (p less than 0.002). In diabetic pregnancies neither a distal femoral epiphysis greater than or equal to 3 mm nor a proximal tibial epiphysis of any dimension correlated precisely with the presence of phosphatidyl glycerol in the amniotic fluid. However, the combination of a distal femoral epiphysis greater than or equal to 3 mm and a proximal tibial epiphysis greater than or equal to 2 mm improved the prediction of phosphatidyl glycerol (sensitivity 83%, specificity 79%, negative predictive value 96%, false-negative rate 17%). The K value in this instance was 0.36 (p greater than or equal to 0.19). It is concluded that the sonographic assessment of the distal femoral and proximal tibial epiphyses and their dimensions in the axial plane may be useful as markers for pulmonic maturity in uncomplicated pregnancies.