Our purpose was to determine the utility of screening for humerus and femur length shortening in prenatal detection of Down's syndrome (trisomy 21). On the. echogenic cardiac focus, relatively short femur and short humerus, iliac wing angle, on the scan, and individualized genetic counseling would be recommended. and does not bear any relationship with heart abnormalities of the baby. fetuses with isolated short femur were compared with a control A short femur diagnosis in a fetus with an otherwise normal .. Fetal Diagnosis and Therapy. Humerus and femur length shortening in the detection of Down's red blood cell counts in small-for-gestational-age fetuses: relationship to.
Neonatal race was classified as African American if the mother reported both herself and the father as African American, as white if the mother reported both herself and the father as white, or biracial if maternal and paternal race differed. Infant ethnicity was similarly classified as Hispanic, non-Hispanic, or multiethnic. Data on markers of bone turnover and concentrations of osteoprotegerin and maternal calcitropic hormone concentrations were published previously 19 Each adolescent attended up to 3 study visits across pregnancy, roughly timed to coincide with early, mid- and late gestation.What We Might Learn in Couples Therapy
At each visit, maternal anthropometric measures were recorded, and a h dietary recall was administered by study personnel using food models to help estimate portion sizes. Tertiles of dietary calcium intake were defined based on the reported calcium intakes in this cohort. Up to 3 times across pregnancy, both standard fetal biometry measures femur length, biparietal diameter, abdominal circumference, and head circumference and humerus length were recorded by certified sonographers.
The curves generated for fetal femur growth in these pregnant adolescents are comparable with similar curve fits generated from data obtained in adult women 13 Fetal humerus length z scores were calculated from published curves generated by Chitty and Altman 21 in adult women, because no published normative fetal humerus curves from adolescent pregnancies exist at present.
At birth, infant weight, length, and head circumference were recorded by clinical staff. All blood samples were allowed to clot at room temperature, before serum was separated by centrifugation. This laboratory participates in the vitamin D External Quality Assessment Scheme as a means of quality assurance.
The season of each blood collection was classified as winter November—Februaryspring March—Aprilsummer May—Augustor autumn September—October by using seasonal classifications for the northeast United States After a high prevalence of vitamin D insufficiency was observed in the first 37 study participants, all subsequent participants found to be vitamin D insufficient at midgestation were provided with an additional IU vitamin D3 at their next prenatal visit and were instructed to take one pill daily over the remainder of gestation.
Compliance with all prenatal supplements provided was queried by self-report at each study visit. Because of the lack of standardized reference ranges for calcitriol concentrations across pregnancy, adolescents were classified as exhibiting 1,25 OH 2D concentrations above or below the mean 1,25 OH 2D value at midgestation and at delivery. Statistical analyses Analyses were performed by using SAS 9. Paired t tests or nonparametric tests were used to assess changes in hormones across gestation within subjects.
Independent t tests or ANOVA were used to determine whether normally distributed variables differed by race, season, or categories of vitamin D status and calcium intake; Wilcoxon's rank-sum test was used for nonparametric data. Simple linear regression was used to explore relations between calcium intake, 25 OH D, and 1,25 OH 2D and fetal skeletal growth. Multiple linear regression was used to control for covariates and interactions between variables and to model statistical predictors of measures of fetal skeletal growth.
Previous research had identified maternal height, prepregnancy BMI, and dairy product intake as predictors of fetal femur length in a group of African American adolescents As such, we initially considered maternal height and prepregnancy BMI as well as infant sex, maternal race, weight gain, smoking status, chronologic age, and gynecologic age as potential predictors of fetal femur and humerus z scores and neonatal birth length.
These variables were controlled for as covariates in the generated models of fetal bone z scores and birth length. Interactions between maternal calcium intake and vitamin D status on fetal and neonatal bone outcomes were assessed statistically.
Using published means and SDs for fetal femur length reported in pregnant adolescents 13we determined that a sample size of participants would provide us with sufficient power 0. Variables were tested for normality by using the Shapiro-Wilks test. Nonnormally distributed variables were log transformed as necessary to ensure normality of the residuals.
Birth data were missing or unavailable in 9 adolescents: Among neonates assessed at delivery, birth length was recorded in the medial chart of In adolescents Gestational age at delivery ranged from Approach to prenatal diagnosis There is a wide range of rare skeletal dyplasias, each with a specific recurrence risk, dysmorphic expression, and implications for neonatal survival and quality of life. Our knowledge of the in utero expression of these syndromes is based on a few case reports and, therefore, in attempting to perform prenatal diagnosis of individual conditions in at-risk families, extrapolation of findings from the perinatal period is often necessary.
The incidental discovery of a skeletal dysplasia on routine ultrasound screening, in a pregnancy not known to be at risk of a specific syndrome, necessitates a systematic examination to arrive at the correct diagnosis.
All limbs must be evaluated see Figure 17, p. Assessment of long bones Shortening of the extremities can involve the entire limb micromelia, such as achondrogenesis, short-rib polydactyly syndrome, diastrophic dysplasia osteogenesis imperfecta type IIthe proximal segment rhizomelia, such as achondroplasiathe intermediate segment mesomelia, such as mesomelic dysplasia or the distal segment acromelia, such as Ellis—Van Creveld syndrome.
The diagnosis of rhizomelia or mesomelia requires comparison of the dimensions of the bones of the leg and forearm with those of the thigh and arm. The femur, however, is abnormally short even in mesomelic dwarfism and, therefore, in our routine fetal abnormality screening, we tend to confine limb measurements to that of the femur.
When dealing with pregnancies at risk for a skeletal dysplasia, both segments of all limbs are measured. The severe limb reductions associated with osteogenesis imperfecta type II, achondrogenesis and thanatophoric, diastrophic, and chondroectodermal dysplasias can be detected by a single measurement of the femur length at 16—18 weeks of gestation.
In the case of achondroplasia, however, the diagnosis may not become obvious until 22—24 weeks and, therefore, serial measurements are necessary; homozygous achondroplasia, which is usually lethal, manifests in abnormally short limbs earlier than the heterozygous form.
A minor degree of lateral curvature of the femur is commonly seen in normal fetuses. Pronounced bowing, however, is observed in association with campomelic dysplasia, thanatophoric dwarfism, autosomal dominant osteogenesis imperfecta, achondrogenesis and hypophosphatasia. In the latter, fractures and callus formation may also be detected.
Reduced echogenicity of bones, suggestive of hypomineralization, is seen in such disorders as hypophosphatasia, osteogenesis imperfecta and achondrogenesis.
Outcome of Fetuses with Diagnosis of Isolated Short Femur in the Second Half of Pregnancy
The virtual absence of ossification of the spine, characteristic of achondrogenesis, may lead to the erroneous diagnosis of complete spinal agenesis. Similarly, the pronounced clarity with which the cerebral ventricles are imaged, as a result of the poorly mineralized globular cranium in cases of hypophosphatasia, may result in the misdiagnosis of hydrocephalus.
Care must be exercised, however, because lesser degrees of hypomineralization may not be detectable. Isolated limb reduction deformities, such as amelia complete absence of extremitiesacheiria absence of the handphocomelia seal limb or aplasia—hypoplasia of the radius or ulna, are often inherited as part of a genetic syndrome Holt—Oram syndrome, Fanconi pancytopenia, thrombocytopenia with absent radii syndrome and are readily diagnosible by ultrasonography in an at-risk fetus.
Other causes of focal limb loss include the amniotic band syndrome, thalidomide exposure and caudal regression syndrome. Evaluation of hands and feet Fetal fingers and toes can be seen, and, with meticulous examination, abnormalities of numbers, shape, movement and attitudes can be recognized.
Several skeletal dysplasias feature alterations of the hands and feet. Polydactyly refers to the presence of more than five digits. It is classified as postaxial if the extra digits are on the ulnar or fibular side and preaxial if they are located on the radial or tibial side.
Outcome of Fetuses with Diagnosis of Isolated Short Femur in the Second Half of Pregnancy
Syndactyly refers to soft tissue or bony fusion of adjacent digits. Clinodactyly consists of deviation of a finger s. Disproportion between hands and feet and the other parts of the extremity may also be a sign of a skeletal dysplasia. Examination of fetal movements Maternal perception of fetal movements is usually decreased in fetuses with skeletal dysplasias, such as achondrogenesis and thanatophoric dysplasia.
Ultrasonography can aid in the diagnosis of conditions characterized by limitation of flexion or extension of the limbs, such as arthrogryposis and multiple pterygium syndrome.
Evaluation of thoracic dimensions Several skeletal dysplasias are associated with a small thorax, and chest restriction leads to pulmonary hypoplasia, which is the common cause of death in these conditions.
The appropriateness of thoracic dimensions can be assessed by measuring the thoracic circumference at the level of the four-chamber view of the heart and examining the thoracic-to-abdominal circumference ratio, the thoracic-to-head circumference ratio, or the thoracic-to-cardiac circumference ratio. Skeletal dysplasias associated with a long narrow thorax include asphyxiating thoracic dysplasia Jeunechondroectodermal dysplasia Ellis—Van Creveldcampomelic dysplasia, Jarcho—Levin syndrome, achondrogenesis and hypophosphatasia.
Hypoplastic thorax is found in short-rib polydactyly syndrome type I, type IIthanatophoric dysplasia, cerebrocostomandibular syndrome, cleidocranial dysostosis syndrome, homozygous achondroplasia, Melnick—Needles syndrome osteodysplastyfibrochondrogenesis and otopalatodigital syndrome type II.