Human fetal hand size and hand maturity in the first half of the prenatal period

The purpose of the present study has been to establish radiographic standards of hand length and finger bone size in the first half of the prenatal period, and to relate these measurements to general fetal size (CRL) and foot length (FL), as well as to the skeletal maturity assessed from a Composite Number of Ossified bones in hand and foot radiographs (CNO). The right hand and foot of each of 251 normal human fetuses (CRL 47–194 mm) were radiographed. From each hand radiograph hand length (DM), third proximal phalangeal bone length (PP) and third metacarpal bone length (MC) were measured. The study showed that third proximal phalangeal and metacarpal bone lengths both provide a valuable basis for estimating hand length. Both hand length and the length of the third metacarpal bone were found to be good predictors of general fetal size (CRL). The study provides standards for the relationships between hand and finger bone sizes, general fetal length and foot length. By combining third metacarpal bone size and skeletal maturity of the hand and foot general fetal development (age and crown-rump length) can be estimated. Insight into normal hand size and finger bone size at different stages of normal development including skeletal maturation is useful in future evaluation of handsize under pathological conditions.     

Is statural growth predictable in utero? Follow-up from the second trimester of gestation to the 8th year of life

ABSTRACT BACKGROUND: It is well known that birth weight is related to later childhood growth and adult height. It can therefore be hypothesized that this relationship exists also for fetal size before birth. OBJECTIVE: To verify whether a child's final height can be predicted by sonographic biometry in utero. SUBJECTS: We evaluated in 116 healthy children both ultrasound measurements in utero and postnatal measurements at a mean age of 6.0 +/- 1.4 years. METHODS: The following fetal ultrasound measurements were obtained: crown-rump length in the first trimester; biparietal diameter, head circumference and femur length in the second and third trimester. RESULTS: Midparental height of the children was correlated both with crown-rump length in the first trimester and with femur length (FL) in the second and third trimester. Predicted adult height was correlated both with FL in the second and third trimester, while present height of the child was correlated with FL only at the third trimester. CONCLUSIONS: FL showed a close relationship with postnatal measurements. For the extreme values of FL, it seems possible to make quite an accurate prediction of the limits of future height. We can reasonably speculate, therefore, that the basis for the future growth of the child can be found in utero.     

Growth and motor development in fetuses of women with type-1 diabetes. I. Early growth patterns

Early embryonic and fetal growth were followed longitudinally in 23 women with type-1 diabetes to investigate whether there was any evidence of early growth delay and, if so, when it originated and when catch-up growth occurred. Weekly crown-rump length (CRL) measurements were taken between 7 and 14 weeks of gestation; the biparietal diameter (BPD) of the fetal head was measured once every 2-4 weeks from 13 to 30 weeks of gestation. Data were compared to those of a control group and to control data published in the literature. The CRL of the fetuses in the diabetic group was generally shorter than that observed normally. Six out of the 23 (26%) fetuses showed true early growth delay (a size smaller than normal by 6 days or more). Growth delay was present from the first recording onwards and must therefore have occurred before the seventh gestational week. Fetal growth (BPD) was found to be normal at around 20 weeks and there was evidence of accelerated growth of the BPD during the second trimester in fetuses that became macrosomic. Early embryonic growth delay was most profound in the women whose periconceptional quality of glucose control was poor, although the relationship with the HbAlc values was not statistically significant. It is concluded that fetuses of women with type-1 diabetes, as a group, have a significantly different growth pattern than control fetuses throughout the first 30 weeks of pregnancy.     

Skeletal abnormalities in fetuses with Down's syndrome: a radiographic post-mortem study

Objective. To evaluate skeletal abnormalities on post-mortem radiographs of fetuses with Down's syndrome. Materials and methods. Biometrical and morphological criteria, which are used for US prenatal detection of trisomy 21, were assessed. Limb long bones, biparietal diameter (BPD)/occipito-frontal diameter (OFD) ratio, ossification of nasal bones and appearance of the middle phalanx of the fifth digit (P2) in 60 fetuses with Down's syndrome were analysed and compared with 82 normal fetuses matched for gestational age (GA) from 15 to 40 weeks' gestation (WG). Results. We observed reduced growth velocity of limb long bones during the third trimester in both groups, but the reduction was more pronounced in the trisomic group. Brachycephaly was found as early as 15 WG in Down's syndrome and continued throughout gestation (sensitivity 0.28, specificity 1). Ossification of the nasal bones, which can be detected in normal fetuses from 14 WG, was absent in one quarter of trisomic fetuses, regardless of GA. The middle phalanx of the fifth digit was evaluated by comparison with the distal phalanx (P3) of the same digit. We found that P2 was not ossified in 11/31 trisomic fetuses before 23 WG, and was either not ossified or hypoplastic in 17/29 cases after 24 WG (sensitivity 0.56, specificity 1). Conclusions. Three key skeletal signs were present in trisomic fetuses: brachycephaly, absence of nasal bone ossification, and hypoplasia of the middle phalanx of the fifth digit. All these signs are appropriate to prenatal US screening. When present, they fully justify determination of the fetal karyotype by amniocentesis. Received: 19 May 1998 Accepted: 19 February 1999     

Analysis of the harmonized growth pattern of fetal organs by multidimensional scaling and hierarchical clustering

The development of an organ may be affected by various growth and differentiation factors released from other organs. These factors are believed to have important effects on the development of multiple organs. To detect and analyze harmonized development among multiple organs, similarities in growth patterns among fetal organs were examined using multivariate analysis. Ninety human fetuses obtained from the Kyoto Collection of Human Embryos were dissected. Harmonized development of organs was evaluated by multidimensional scaling and cluster analysis using measurements (length, width, height, and weight) of the fetal organs. Similar growth patterns were observed between the brain, including cerebrum, diencephalon, and midbrain (cerebrum‐to‐midbrain [Cer‐Mid]), and pituitary (crown‐rump length [CRL] 95–155 mm). Further, similar growth patterns were observed between the liver and Cer‐Mid and cerebellum (Cb; CRL 156–202 mm), and between Cer‐Mid and Cb (CRL 203–253 mm). Similarities in growth patterns were also observed between right and left lungs (CRL 99–235 mm) and between the aorta and heart (CRL 139–187 mm), but not between the lung and pulmonary trunk. These findings revealed synchronized development among fetal organs and suggested a functional and structural relationship among different organs in the prenatal period. These relationships include the existence of common factors in organ development, such as cross‐talk mediated by humoral factors, and the presence of an anatomical and functional relationship in the fetal circulatory system.     

Development of the pons in human fetuses

Morphometric and histological studies of the pons were performed by light microscopy in 28 cases of externally normal human fetuses ranging from 90 to 246 mm in crown-rump length (CRL) and from 13 to 28 weeks of gestation. The brainstems of fetuses were embedded in celloidin or paraffin, and transverse sections were prepared. The pons was divided into two regions at the most ventral margin of the medial lemniscus at the level of the motor trigeminal nucleus. The relationships between the total dorsoventral length, ventral length, and dorsal length of the pons versus CRL and gestational ages were calculated, and empiric formulas were fitted. It was found that the ventral portion increased in size more rapidly than the dorsal portion. The proportion of the ventral portion in the total dorsoventral length was constitutively higher than that of the dorsal portion in the present range of CRL. In the pontine nuclei, from 235 mm in the CRL, some large cells with rich cytoplasm, pale nuclei, and a distinct nucleolus appeared on the dorsal side of the pyramidal tract. According to Weigert stained preparations, the first myelinated fibers in each motor root of the trigeminal, abducent, and facial nerves were recognized at 130-140 mm in CRL and the medial lemniscus at 230-235 mm.     

Prenatal Detection of Coarctation of the Aorta in a Non-selected Population: A Prospective Analysis of 10 Years of Experience

The objective of this study was to assess the ability of different parameters to identify fetuses requiring neonatal care for coarctation of the aorta (CoA). Between January 2003 and December 2012, 175 fetuses referred for great vessel disproportion were divided into two groups: group A (n = 51) with high risk of CoA and delivery planned in tertiary care referral center and group B (n = 124) with no increased risk of CoA. In group A, diagnosis of CoA was confirmed in 38/51 (74 %). In group B, 2/124 had CoA. Multiple logistic regression analysis identified the best combination as diffusely hypoplastic and/or angular aortic arches, ventricular septal defect and aortic valve diameter <5 mm at 36-week gestational age (GA). Positive predictive value was 75 % when vessel disproportion was noted before 28-week GA and 73 % in the third trimester. Postnatal diagnosis involved 38 cases of CoA which had not been referred. One case of CoA diagnosed after birth was referred prenatally for difficulty of screening without any defect. The results of our prospective study are in agreement with those of previous series, but our false positive rate was lower especially when the diagnosis of vascular disproportion was made at third trimester. The performance of fetal cardiac screening does not seem to be very good, but prenatal diagnosis is probably not always possible: Among our three false negative cases, two had isolated vascular disproportion and the third no risk factors.     

Development of olfactory epithelium in the human fetus: Scanning electron microscopic observations

Aims:  Human olfactory epithelium becomes functional at birth, but prenatal development remains unclear. In the present study, we aimed to clarify the development of human olfactory epithelium using scanning electron microscopy (SEM).
Methods:  The development of human olfactory epithelium was observed in 24 externally normal fetuses, which were formalin-fixed and long-preserved, with a crown-rump length (CRL) of 102–336 mm (gestational week 14–38). The olfactory mucosa in the superior wall of the nasal septum near the choana were dissected and observed under SEM. We examined the number of olfactory vesicles per unit area, diameter of olfactory vesicles, and number and length of cilia on olfactory vesicles.
Results:  At circa (ca) CRL 100 mm (ca 14 weeks), olfactory epithelium displayed several olfactory vesicles with 1–2 short cilia per unit area. At ca CRL 150 mm (ca 18 weeks), olfactory vesicles were present in small clusters, and cilia were longer. At CRL lager than 225 mm (ca 26 weeks), olfactory vesicles became located separately from each other, while length and number of cilia per olfactory vesicle were further increased.
Conclusion:  The present findings suggest that fetal olfactory epithelium becomes morphologically almost the same as that in adults in late gestation, much later than previously thought.     

Development of fetal intestinal length during 2nd-trimester in normal and pathologic pregnancies

Linear growth of the human fetal gastrointestinal tract is not often discussed in the literature, and little is known about the effects of chromosomal abnormalities and intrauterine growth restriction (IUGR) on intestinal length, especially during the 2nd trimester. Accurate evaluation of intestinal length and knowledge of normal and reference values are of clinical importance. For example, intestinal resection may be necessary in preterm infants with necrotizing enterocolitis or mid-gut volvulus, and the surgeon should use data to be judicious in the amount removed. Linear measurements are essential in evaluating fetal development ultrasonographically and are an integral part of the postmortem examination. The intestinal lengths of 203 2nd-trimester fetuses and premature infants were measured. Small intestine length (SIL), colon length (CL), total bowel length (TBL; TBL = SIL + CL), and the length of the appendix (AL) increased with gestational age. No differences between the genders were observed. Colon length increased secondary to maceration, but no such effects were shown on SIL, TBL, or AL. No differences were shown in relation to IUGR. Small intestine length, CL, and TBL, but not AL, were shorter in fetuses with trisomy 21. Appendix length was not affected by any of the studied factors. We propose that the measurement of the length of the appendix may be used as an additional parameter for the postmortem evaluation of gestational age. Furthermore, its assessment may have potential as an ultrasonographic indicator of gestational age, particularly for the 2nd trimester.     

Cyclooxygenase-2 in human perinatal lung

Cyclooxygenases-1 and -2 are the key enzymes in the conversion of arachidonic acid to prostanoids. Cyclooxygenase-2 (COX-2) takes part both in inflammation and in control of cell growth. COX-2 immunohistochemistry was performed on lung tissues from autopsies, with four groups included: fetuses (n = 4, GA = 16.0 to 32.0 wk), preterm infants (n = 10, GA = 23.0 to 29.9 wk), term infants (n = 6, GA = 38.7 to 42.0 wk), and infants with bronchopulmonary dysplasia (BPD) (n = 4, GA = 28.9 to 30.7 wk). COX-2 staining occurred exclusively in the epithelial cells resembling type II pneumocytes in the alveolae, and in ciliated epithelial cells in the bronchi. In fetuses, moderate intensity alveolar staining was seen in 90-100% cells lining the alveolar epithelium. In preterm infants, high intensity alveolar staining was seen in a scattered pattern. In term infants, the alveolar staining was also scattered, but with a lower proportion of positive cells. In BPD no staining appeared in alveolar epithelial cells. The most intense bronchial staining was found in fetuses and the least intense in term infants; staining was also seen in BPD. COX-2 is present in human perinatal lung from the gestational age of 16 wk, in a changing pattern. We suggest that COX-2 may, in addition to participating in inflammation, also play a developmental role in the perinatal lung.     

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.     

Azosemide-Induced Fetal Wavy Ribs and Their Disappearance after Birth in Rats

ABSTRACT Azosemide produced bent long bones such as wavy ribs in rat fetuses, but these abnormalities could not be found in the adult offspring. In the present study, the morphological sequence from appearance to disappearance of wavy ribs was examined in cartilage-bone double stained specimens of fetuses and pups from mothers treated with azosemide on day 16 of gestation. The first detected change of the skeletal abnormalities was inhibition of bone deposition in the ossification centers of fetuses on day 17 of gestation. A bend first appeared on day 18 of gestation, and consisted of cartilage and portion stained neither alcian blue nor alizarin red S. Ossification began at this stage. From day 19 of gestation onward, ossification progressed toward the ends of the cartilage model including the bent region. The bend disappeared in most pups as bone in the bent region grew on days 10–14 postpartum. The present findings imply that the bend may be caused by difference in growth between cartilaginous and unstained portions, and a surface remodeling of bones may straighten the bend in the subsequent bone growth.     

Effect of a micronutrient‐rich snack taken preconceptionally and throughout pregnancy on ultrasound measures of fetal growth: The Mumbai Maternal Nutrition Project (MMNP)

Improving micronutrient intakes of under‐nourished mothers in low‐ and middle‐income countries increases birth weight, but there is little data on the nature and timing during gestation of any effects on fetal growth. Ultrasound measures of fetal size were used to determine whether and when a food‐based supplement affected fetal growth. Non‐pregnant women living in Mumbai slums, India (N = 6,513), were randomly assigned to receive either a daily micronutrient‐rich snack containing green leafy vegetables, fruit, and milk (treatment) or a snack made from lower‐micronutrient vegetables (control) in addition to their usual diet from before pregnancy until delivery. From 2,291 pregnancies, the analysis sample comprised 1,677 fetuses (1,335 fetuses of women supplemented for ≥3 months before conception). First‐trimester (median: 10 weeks, interquartile range: 9–12 weeks) fetal crown‐rump length was measured. Fetal head circumference, biparietal diameter, femur length, and abdominal circumference were measured during the second (19, 19–20 weeks) and third trimesters (29, 28–30 weeks). The intervention had no effect on fetal size or growth at any stage of pregnancy. In the second trimester, there were interactions between parity and allocation group for biparietal diameter (p = .02) and femur length (p = .04) with both being smaller among fetuses of primiparous women and larger among those of multiparous women, in the treatment group compared with the controls. Overall, a micronutrient‐rich supplement did not increase standard ultrasound measures of fetal size and growth at any stage of pregnancy. Additional ultrasound measures of fetal soft tissues (fat and muscle) may be informative.     

Three-dimensional first trimester fetal volumetry: comparison with crown rump length

BACKGROUND: Ultrasonographic volumetry measurements of human fetus have become possible using three-dimensional ultrasound systems. OBJECTIVE: To evaluate the weekly increase of fetal volume during the first trimester of normal pregnancies compared to the crown rump length and creating a first trimester fetal volume nomogram. METHODS: Crown rump length and three-dimensional ultrasonographic volumetry measurements performed on 72 first trimester fetuses using virtual organ computer aided analysis (VOCAL). RESULTS: A significant direct correlation (r = 0.939) was found between the calculated fetal volumes and crown rump lengths. A 6-12 weeks gestation fetal volume nomogram was proposed. CONCLUSION: Fetal volume database in the first trimester may serve as a reference table for diagnosis of early pregnancy failure.     

Incidence of Bone Marrow Involvement in Ewing's Sarcoma: Value of Extensive Investigation of the Bone Marrow

Purpose: Bone marrow (BM) status is a critical matter when intensified chemotherapy with bone marrow rescue is proposed to improve the survival of patients with poor prognosis Ewing's sarcoma (ES): metastatic or relapsing disease. A systematic bone marrow investigation was performed in all the patients with newly diagnosed ES or relapsing ES to assess their BM status. Patients and Methods: From January 1985 to February 1989, 59 untreated patients and five patients at the time of relapse had a bone marrow investigation under general anesthesia: two BM biopsies and two BM aspirates until May 1986, then two BM biopsies and 10 BM aspirates. The classical method of smearing each BM aspirate was compared to cytocentrifugation of the pool of BM samples after gradient density separation. Results: The BM was involved in 13 of 59 untreated patients. BM was the single site of metastatic spread in only one patient but was involved in 52% of the patients with metastatic disease at other sites. This involvement was focal in several patients and frequent discrepancies were noted between the aspirates and biopsies at the various sites explored. The number of positive cases of BM involvement discovered by the two methods is somewhat limited. However preliminary results indicate a superior rate of positive smears with the pool technique which did however fail to detect involvement in some cases. Conclusions: The present study indicates that 1) BM involvement is a frequent event in metastatic ES (52%); 2) is often multifocal and therefore requires extensive BM investigation; and 3) further investigation of the pool technique to facilitate the BM screening is warranted. © 1995 Wi1ey-Liss, Inc.     

Maternal administration of betamethasone inhibits proliferation induced by fetal tracheal occlusion in the nitrofen rat model for congenital diaphragmatic hernia: a placebo-controlled study

Purpose  Fetal tracheal occlusion (TO) is offered to fetuses with severe pulmonary hypoplasia due to congenital diaphragmatic hernia (CDH). TO induces lung growth, but even when performed minimally invasive, there is a risk for iatrogenic preterm delivery. Whenever this is anticipated, maternal glucocorticoids (GC) may be given to enhance lung maturation. The pulmonary effects of GC in fetuses with CDH that underwent TO are yet poorly defined. Therefore, we conducted a placebo-controlled study in the nitrofen (NF) rat model for CDH. Methods  Pregnant rats were gavage fed NF or olive oil (OO) on ED9.5. At ED19.0, fetuses were either assigned to TO or left untouched. Maternal betamethasone (BM) or saline (PLAC) was administered on ED20. Necropsy was done on ED21.5 to obtain lung-to-body-weight ratio (LBWR), and perform quantitative RT-PCR and fluorescent immunostaining for Ki-67 and proliferating cell nuclear antigen (PCNA) in fetal lungs. Results  CDH fetuses had a lower LBWR than normal fetuses, but comparable pulmonary PCNA and Ki-67 expression levels. TO increased LBWR, irrespective of maternal BM or PLAC. However, BM but not PLAC inhibited proliferation in TO and unoperated fetuses. Conclusion  Rats with NF-induced CDH have hypoplastic lungs with normal proliferation indices. TO triggers proliferation, an effect countered by BM. Winner of Novartis Awards.     

新生适于胎龄儿骨转换标志物与骨声波传导速度的关系

目的：研究新生适于胎龄儿Ⅰ型前胶原羧基端前肽（PICP）、尿脱氧吡啶啉（DPD）及骨声波的传导速度（SOS）随胎龄变化的规律,探讨骨转换标志物和骨SOS的关系。方法：共选取65例新生适于胎龄儿为研究对象,根据胎龄分为早产儿组（≤34周,14例）,晚期早产儿组（>34周至<37周,13例）,足月儿组（≥37周,38例）。所有研究对象均测量出生体重、身长,采用Ponderal指数（PI）估测新生儿营养状态;生后7?d内采集静脉血测定血PICP水平;收集尿液测定尿DPD、尿肌酐（Cr）水平;生后7 d内超声定量技术测量左侧胫骨声波的传导速度（SOS）。结果：胎龄、出生体重、身长及PI值在3组间的差异均有统计学意义（分别F=140.199、47.042、46.877、11.898,均P<0.01）,且出生体重、身长和PI值随胎龄增加而增加。3组之间PICP、DPD/Cr、SOS的差异有统计学意义（分别F=30.384、21.761、20.052,均P<0.01）,且胎龄越大,PICP及DPD/Cr水平越低,骨SOS越高。PICP、DPD/Cr水平与胎龄、出生体重及骨SOS呈负相关（P<0.01）;而骨SOS与胎龄和出生体重呈正相关（P<0.01）,在校正了胎龄、出生体重后依然存在相关关系。结论：新生适于胎龄儿骨转换生化指标和胎龄、出生体重及骨SOS呈负相关;新生适于胎龄儿的高骨转换状态对骨健康不利。     

Lack of Thy1 (CD90) expression in neuroblastomas is correlated with impaired survival

Neuroblastoma (NBL) is the most common solid tumor in children. Tumors in advanced stage or with positive risk factors still have a poor prognosis. Thy1 (CD90) is a membrane glycoprotein expressed in thymus, retinal ganglionic cells, and several types of stem cells. The aim of this study was to assess Thy1 expression in NBL and analyze the correlation with clinical outcome. Sixty-three specimens of NBL were stained for Thy1 on a tissue microarray by immunohistochemistry. Fresh frozen tumor tissues were used for RNA isolation, and RT-PCR analysis for Thy1-mRNA expression was performed. Patients’ survival data were correlated with Thy1 status using a log rank test and a Cox regression multivariate analysis. Thy1 was expressed on 51 (81%) of the tumors. Kaplan–Meier survival analysis showed a significantly impaired survival in patients with NBL missing Thy1 (P < 0.005 by log-rank test). A multivariate Cox regression showed an independent prognostic value of Thy1 status for overall survival (P < 0.05). In addition, the frequency of events and deaths was significantly higher in the group of patients with Thy1 negative tumors, as assessed by ANOVA analysis (P < 0.05 by F-test). The data showed that Thy1-negative NBL patients have a significantly impaired overall survival compared with Thy1-positive NBL patients. Thus, Thy1 seemed to be a marker with a specific prognostic value in NBL patients. Future studies are aiming at the biological role of this marker in the tumor cell differentiation.     

Prediction of chronic neonatal lung disease in very low birthweight neonates using clinical and radiological variables.

In a prospective observational study, the fatty acid content of human umbilical artery and vein wall phospholipids was determined in fetuses classified according to their change in abdominal circumference during the third trimester. Three groups were identified: appropriate for gestational age (AGA; 24 infants) and small for gestational age (SGA; 38 infants) with normal antenatal growth rate, and SGA with fetal growth retardation (22 infants). The venous linoleic acid (18:2 omega 6) content (expressed as a percentage of the total fatty acids identified) was greater in growth retarded SGA fetuses (3.5 (0.6)%) than in SGA fetuses with a normal growth rate (3.1 (0.5)%) and AGA fetuses (3.0 (0.5)%), whereas the venous contents of eicosatrienoic (20:3 omega 6) and docosahexaenoic acid (22:6 omega 3) were lower. In growth retarded SGA fetuses, the venous and arterial 20:3 omega 6 content correlated with the change in abdominal circumference. In SGA fetuses with a normal growth rate, lower contents of arterial 18:2 omega 6 and 22:6 omega 3 were associated with a smaller change in abdominal circumference and birth weight. Different metabolic derangements appear to underly normal and subnormal growth rate in SGA fetuses, suggesting that different strategies of dietary intervention may be required to aid fetal growth and reduce the sequelae of fetal growth retardation.