Embryoscopic demonstration of hemorrhagic lesions on the human embryo after placental trauma

OBJECTIVE

The purpose of this study was to evaluate embryoscopically the effect of placental trauma on the human embryo.

STUDY DESIGN

Patients undergoing elective first-trimester termination of pregnancy underwent transcervical embryoscopy both before and after chorionic villus sampling. If hemorrhagic lesions were not observed on the fetus after chorionic villus sampling, partial placental detachment was performed with a blunt instrument, and the fetus was again observed.

RESULTS

Hemorrhagic lesions were observed in 20 of 43 fetuses. In 13 of them, the lesions occurred after placental trauma with the chorionic villus sampling catheter alone (30%), whereas lesions were observed in the remaining seven patients after additional blunt placental disruption. The lesions were located most frequently on the cephalic region, and they grew in size during the observation period. Gestational age or amount of chorionic villus sampling tissue was not different between fetuses with or without lesions.

CONCLUSION

Placental trauma results in embryoscopically demonstrable hemorrhagic lesions on the human embryo. Whereas some of these lesions may be of no consequence, others may lead to permanent changes. If similar lesions occur in deeper tissues, they could cause disruptions in development and conceivably could be related to anomalies reported in infants born to women who have had chorionic villus sampling procedures. Embryoscopy affords the opportunity to study possible mechanisms involved in the occurrence of anomalies.

Fetal blood sampling and cytogenetic abnormalities

From September 1984 to April 1991, we performed cytogenetic analysis on fetal blood samples from 214 second- and third-trimester pregnancies. One hundred and thirty-four cases were referred to consider the possibility of chromosomal mosaicism following amniocyte studies. The confirmation rate of mosaicism is at 0 per cent (0/9), 1.4 per cent (1/70), and 40 per cent (22/55) for cases of level I, level II, and level III mosaicism, respectively. Four out of 17 cases were positive for the diagnosis of fragile X syndrome. Of 63 cases with abnormal ultrasound findings, blood disorders, or other genetically related clinical conditions, 11 were found to have a chromosome abnormality. Fetal blood sampling is a valuable adjunct to other methods in the prenatal diagnosis of chromosomal mosaicism or pseudomosaicism. It is also useful when rapid cytogenetic diagnosis is desired because of malformations detected in pregnancies at a late gestational age.

A randomized comparison of transcervical and transabdominal chorionic-villus sampling. The U.S. National Institute of Child Health and Human Development Chorionic-Villus Sampling and Amniocentesis Study Group

BACKGROUND

Chorionic-villus sampling is done in early pregnancy to obtain fetal cells for the prenatal diagnosis of genetic and chromosomal defects. Transcervical chorionic-villus sampling has been shown to be safe and effective in national trials. Recently, an alternative transabdominal technique has been suggested as potentially easier and safer.

METHODS

From April 1987 through September 1989, we prospectively compared transcervical and transabdominal chorionic-villus sampling in 3999 women with singleton pregnancies in whom the risk of a genetically abnormal fetus was increased. Women between 7 and 12 weeks of gestation underwent ultrasonographic evaluation of placental and uterine position. Those with active vaginal infections, active bleeding, or cervical polyps were excluded. If the obstetrician thought either sampling procedure was acceptable, the woman was asked to consent to random assignment to one of the two procedures. Both groups were followed to determine the outcome of pregnancy and the rate of spontaneous fetal loss after chorionic-villus sampling.

RESULTS

Among the 3999 women who entered the study, sampling was attempted in 3873 (97 percent), 1944 of whom had been assigned to undergo transcervical sampling and 1929 to undergo transabdominal sampling. Of these 3873 women, sampling was eventually successful in 3863. Sampling was successful after a single insertion of the sampling instrument in 94 percent of the transabdominal procedures and 90 percent of the transcervical procedures. Among the women with cytogenetically normal pregnancies who had sampling because of maternal age, the rate of spontaneous fetal loss through 28 weeks of pregnancy was 2.5 percent in the transcervical-sampling group and 2.3 percent in the transabdominal-sampling group (difference, 0.26 percent; 95 percent confidence interval, -0.5 to 1.0 percent).

CONCLUSIONS

Transabdominal and transcervical chorionic-villus sampling appear to be equally safe procedures for first-trimester diagnosis of fetal abnormalities.

Trisomy 5 mosaicism detected prenatally with an affected liveborn

This paper reports a case of chromosomal mosaicism for trisomy 5 recovered from amniotic fluid cells and from skin fibroblasts of a liveborn dysmorphic male. Routine amniocentesis was performed at 16 weeks' gestation because of parental concern. Trisomy 5 cells were measured from 25 per cent of amniocytes from two culture vessels. No further invasive testing was performed until 32 weeks' gestation, at which time ultrasound examination showed a fetus with intrauterine growth retardation. Fetal blood sampling was then performed, with only karyotypically normal cells recovered. At birth, the child was found to have multiple dysmorphic features and congenital anomalies, including an eventration of the diaphragm and ventricular septal defect, both of which required surgical correction. Chromosomal analysis of cord blood lymphocytes indicated 46,XY; however, 20 per cent of the cultured fibroblasts obtained from the chest skin at the incision site for diaphragmatic repair had a 47,XY, +5 karyotype. Trisomy 5 mosaicism may be another example of tissue-limited mosaicism. Fetal blood sampling can then be falsely reassuring. Furthermore, because some cell lines rarely appear in lymphocyte populations, cytogenetic analysis of multiple tissues is warranted as part of the evaluation of individuals with developmental delay and dysmorphic features.

Fetal humeral length to detect Down syndrome

OBJECTIVE

Our aim was to evaluate the utility of ultrasonographic humeral length measurements for detection of fetuses with Down syndrome in the midtrimester of gestation.

STUDY DESIGN

Ultrasonographic biometry data obtained before genetic amniocenteses on 43 fetuses with Down syndrome and 204 randomly chosen normal fetuses were analyzed. Regression equations relating biparietal diameter to humeral length and femoral length were used to calculate ratios of observed-to-expected length and sensitivity and specificity at various cutoff points.

RESULTS

Humeral length in Down syndrome fetuses was significantly shorter than in normal controls (p less than 0.001). A ratio of 0.90 for observed/expected humeral length yielded a sensitivity of 28%, a specificity of 91%, and positive predictive values of 1.23% and 0.41% in populations at risk for Down syndrome of 1 in 250 and 1 in 750, respectively. The equivalent ratio for femoral length yielded a sensitivity of 19%, a specificity of 91%, and positive predictive values of 0.87% and 0.28% for baseline risks of 1 in 250 and 1 in 750, respectively.

CONCLUSIONS

The sensitivity of fetal humeral length measurements for Down syndrome detection in our hands was remarkably lower than previously reported. Independence of this parameter from currently used serum screening markers has not been established; therefore implementation in screening programs is not advisable at this point.

Cytogenetic results from the U.S. Collaborative Study on CVS

Cytogenetic data are presented for 11,473 chorionic villus sampling (CVS) procedures from nine centres in the U.S. NICHD collaborative study. A successful cytogenetic diagnosis was obtained in 99.7 per cent of cases, with data obtained from the direct method only (26 per cent), culture method only (42 per cent), or a combination of both (32 per cent). A total of 1.1 per cent of patients had a second CVS or amniocentesis procedure for reasons related to the cytogenetic diagnostic procedure, including laboratory failures (27 cases), maternal cell contamination (4 cases), or mosaic or ambiguous cytogenetic results (98 cases). There were no diagnostic errors involving trisomies for chromosomes 21, 18, and 13. For sex chromosome aneuploidies, one patient terminated her pregnancy on the basis of non-mosaic 47,XXX in the direct method prior to the availability of results from cultured cells. Subsequent analysis of the CVS cultures and fetal tissues showed only normal female cells. Other false-positive predictions involving non-mosaic aneuploidies (n = 13) were observed in the direct or culture method, but these cases involved rare aneuploidies: four cases of tetraploidy, two cases of trisomy 7, and one case each of trisomies 3, 8, 11, 15, 16, 20, and 22. This indicates that rare aneuploidies observed in the direct or culture method should be subjected to follow-up by amniocentesis. Two cases of unbalanced structural abnormalities detected in the direct method were not confirmed in cultured CVS or amniotic fluid. In addition, one structural rearrangement was misinterpreted as unbalanced from the direct method, leading to pregnancy termination prior to results from cultured cells showing a balanced, inherited translocation. False-negative results (n = 8) were observed only in the direct method, including one non-mosaic fetal abnormality (trisomy 18) detected by the culture method and seven cases of fetal mosaicism (all detected by the culture method). Mosaicism was observed in 0.8 per cent of all cases, while pseudomosaicism (including single trisomic cells) was observed in 1.6 per cent of cases. Mosaicism was observed with equal frequency in the direct and culture methods, but was confirmed as fetal mosaicism more often in cases from the culture method (24 per cent) than in cases from the direct method (10 per cent). The overall rate of maternal cell contamination was 1.8 per cent for the culture method, but there was only one case of incorrect sex prediction due to complete maternal cell contamination which resulted in the birth of a normal male.(ABSTRACT TRUNCATED AT 400 WORDS)

First-trimester biochemical and molecular diagnoses using chorionic villi: high accuracy in the U.S. collaborative study

The accuracy of biochemical and molecular prenatal diagnoses using chorionic villi as the fetal source was assessed by seven centres participating in the NICHD collaborative study on the safety and accuracy of chorionic villus sampling (CVS) and amniocentesis. Of 601 pregnancies studied, biochemical methods were used to determine the diagnosis in 283 fetuses at risk for 35 different metabolic disorders. Fifteen different lysosomal storage diseases accounted for 81 per cent of the biochemical prenatal diagnoses performed, with 57 per cent of these pregnancies at risk for Tay-Sachs disease. No errors were made in the biochemical diagnoses that predicted affected or unaffected fetuses. However, the diagnoses of certain disorders (e.g., mucopolysacchariodosis type IH, metachromatic leukodystrophy, and Krabbe disease) occasionally required confirmatory studies in cultured amniocytes because the enzyme results were inconclusive in direct and/or cultured villi or due to the presence of a pseudodeficiency allele. Of these, only the diagnosis of a fetus at risk for Krabbe disease remained inconclusive after special studies to discriminate between mutant and pseudo-deficiency alleles. Recombinant DNA techniques were used to predict the diagnosis of 318 fetuses at risk for 16 different disorders in which the defective disease gene could be detected either directly or by linkage analysis to a nearby polymorphic marker. Of these, 32 per cent were for haemoglobinopathies, 25 per cent for cystic fibrosis, 24 per cent for Duchenne or Becker muscular dystrophy, and 7 per cent for haemophilias. Pregnancies at risk for known disorders with specific molecular lesions (e.g., sickle cell disease) were accurately diagnosed in direct and/or cultured villi. Diagnoses requiring analyses with closely linked polymorphic markers were occasionally uniformative or inconclusive. Maternal contamination was not reported in any biochemical or molecular-based diagnosis. These studies document the high accuracy and rapidity of both biochemical and mutation-specific prenatal diagnoses with direct and cultured chorionic villi.

Risk factors associated with transcervical CVS losses

Factors found to be associated with pregnancy loss after transcervical CVS were race (higher for non-white), history of spontaneous abortion, unplanned pregnancy, history of spotting or bleeding during the pregnancy prior to CVS, and placental position (higher for fundal or lateral locations). Whether the increase in loss risk is due to the factor, per se, or the factor plus the CVS cannot be determined due to the lack of appropriate control data.

Postnatal placental confirmation of trisomy 2 and trisomy 16 detected at chorionic villus sampling: a possible association with intrauterine growth retardation and elevated maternal serum alpha-fetoprotein

Detection of trisomy 2 and trisomy 16 mosaicism through chorionic villus sampling (CVS) is not an infrequent finding. We describe here two cases, one of non-mosaic trisomy 2 and the other of high level mosaicism for trisomy 16. Amniocentesis in both cases demonstrated non-mosaic 46,XY karyotypes. Each pregnancy continued to delivery of liveborn, normal-appearing boys; both pregnancies were complicated by severe intrauterine growth retardation (IUGR). Postnatal studies of placental biopsies in both cases confirmed the original CVS findings, whereas cord blood karyotypes were normal in both boys. Both children have demonstrated adequate catch-up growth.

Prenatal diagnosis of a fetus with terminal deletion of chromosome 1 (q41)

Many authors have suggested that individuals affected by a terminal 1q deletion display a phenotypically definable and recognizable syndrome. In all of the 27 cases reported to date, the breakpoints were at band q42 or distally to it. To our knowledge, we report the first case of a terminal 1q41 deletion. Diagnosis was made prenatally by amniocentesis, following ultrasonographic diagnosis of omphalocele, cerebral ventriculomegaly, and increased nuchal fold thickness in a 19-week female fetus. Multiple facial and extremity features were consistent with the proposed distal 1q deletion syndrome; omphalocele, however, has not been reported previously. The absence of liver herniation into the omphalocele sac in this case supports the previously reported association of this finding with chromosomal anomalies.

Prenatal diagnosis and outcomes of five cases of mosaicism for an isochromosome of 20q

Five cases of mosaicism for an isochromosome of 20q have been detected from a total of 50,000 cases analysed for prenatal diagnosis by amniocentesis. Karyotypes were designated mos 46,X-/46,X-,i(20q). In all cases, the abnormal cell line was detected in more than one primary culture, thus fulfilling the criterion for true (level III) mosaicism. Indications for prenatal diagnosis were parental anxiety (two cases), low maternal serum alpha-fetoprotein (AFP) (two cases), and high maternal serum AFP (one case). Level II ultrasounds on all five fetuses were normal, and the abnormal cell line was never detected in fetal blood and/or cord blood. All five pregnancies were continued and had normal outcomes, with birth weights ranging from 2.4 to 3.8 kg. The development of all five children has been normal, with the oldest child in the study now 4 years of age. We suggest that the abnormal cell line in each case was of extrafetal origin, and that this may be one of the more common examples of this phenomenon, occurring in approximately 1/10,000 prenatal diagnoses. Mosaicism i(20q) may have been missed in the past because of the higher resolution necessary to detect this subtle change.

Degradation of intraendosomal insulin by insulin-degrading enzyme without acidification

The nature of insulin degradation within endosomes was studied in vitro. Radiolabeled insulin was perfused into rat liver via the portal vein, and insulin-containing endosomes were prepared by differential centrifugation. The endosomes were incubated in various buffers, and hormone degradation was monitored by Sephadex G-50 chromatography and high-performance liquid chromatography (HPLC). Endosomes incubated in simple imidazole or HEPES (pH 7.4) buffers rapidly degraded insulin to intermediate- and then to low-molecular-weight products that were lost from the vesicles. HPLC analysis of insulin-sized material showed the products to be the same as those produced by intact cells. The endosomes did not acidify in these buffers (as assessed by the acridine orange method), and ATP had no effects. When the endosomes were incubated in a chloride-containing buffer, degradation was greatly inhibited, and acidification did not occur. Both insulin degradation and acidification were activated when Mg-ATP was added to this buffer system. HPLC analysis of the products generated in this system revealed not only typical cellular products but additional less hydrophobic products. Western-blot analysis of endosomal protein with anti-insulin-degrading enzyme antibody showed this enzyme to be present. In conclusion, isolated endosomes rapidly and completely degrade insulin through products that are typical of cellular degradation without requiring acidification. Chloride-containing buffers inhibit endosomal degradation, which is reversed by Mg-ATP, but this system does not mimic cellular degradation. At least one of the enzymes responsible for insulin degradation is insulin-degrading enzyme.

Diagnosis and significance of cystic hygroma in the first trimester

Thirty cases of cervical cystic hygroma were diagnosed in the first trimester of pregnancy. Karyotype analysis was available in 29 (97 per cent). Fifteen (52 per cent) had a chromosomal abnormality. The ultrasound appearance was described as posterior cervical, lateral cervical, or cervical hygroma with hydrops. Of the 14 euploid embryos, six were electively aborted, two are undelivered, and six have been delivered as phenotypically normal infants. In cases in which the chromosomes were normal and the pregnancy continued, all lesions resolved by 18 weeks.

Elevated maternal serum alpha-fetoprotein concentration and fetal chromosomal abnormalities

Amniocentesis was performed in 1038 patients with elevated maternal serum alpha-fetoprotein (MSAFP) concentrations. Patients were divided into two groups based upon the amniotic fluid AFP concentration. Group 1 (N = 964) had a normal amniotic fluid AFP concentration and group 2 (N = 74) had elevated amniotic fluid AFP. Fetal chromosomal results were reviewed from the study population, with the finding of eight major fetal chromosomal abnormalities. Of the eight fetal chromosomal abnormalities, five were associated with elevated amniotic fluid AFP and three were associated with normal amniotic fluid AFP. The sensitivity and specificity of elevated amniotic fluid AFP concentrations in screening for a fetal chromosomal abnormality were 62.5 and 93.3%, respectively. In women with elevated MSAFP but normal amniotic fluid AFP concentrations, the probability of a major fetal chromosomal abnormality is extremely small.

Yolk sac failure in embryopathy due to hyperglycemia: horseradish peroxidase uptake in the assessment of yolk sac function

We described previously the morphologic alterations of the visceral endodermal yolk sac cells of rat conceptuses cultured under hyperglycemic conditions which occurred concomitantly with major embryonic malformations. To determine whether the transport function of the yolk sac was impaired simultaneously as a result of these hyperglycemic conditions, horseradish peroxidase was used as a tracer protein to assess the transport function of the visceral endodermal yolk sac cells of conceptuses cultured in both control and hyperglycemic media. Cellular uptake of peroxidase, which was added to the culture medium for 3 or 24 hours, was observed in controls. This differed from the marked diminution in peroxidase uptake seen in conceptuses cultured in hyperglycemic medium. These results demonstrate that during hyperglycemia-induced embryopathy, there is concomitant yolk sac failure evidenced by morphologic alterations and impaired endocytosis. These findings therefore strengthen our hypothesis that diabetes-related malformations, as demonstrated experimentally in rat conceptuses, are associated with impairment in the structure and functions of the visceral yolk sac cells during a critical period of organogenesis.

Antenatal diagnosis of 45,X/48,XYYY

A diagnosis of 45,X/48,XYYY was made antenatally. Counseling this case was hampered by the paucity of literature describing the phenotype of patients with this chromosome constitution. The fetus had ambiguous external genitalia, a horseshoe kidney, a cerebral cortical cyst and arachnodactyly.

Retroendocytosis of insulin in a cultured kidney epithelial cell line

It has been generally accepted that in renal tubular epithelium endocytosed proteohormones are transported to lysosomes where they undergo complete hydrolysis. En route, as endosomal pH falls, the proteohormone uncouples from the endocytosed membrane binding site, which recycles to the cell surface. However, studies in other tissues have uncovered alternate intracellular pathways for proteins. One such pathway is retroendocytosis (endocytosis then exocytosis). To determine whether a retroendocytotic pathway exists for insulin in renal epithelium, a study was carried out with confluent monolayers of a proximal-like opossum kidney cell line that exhibits receptor-mediated endocytosis of insulin. Cells were preloaded with 125I-labeled insulin (4 X 10(-10) M) for 30 min, surface-bound insulin was then removed by acid washing, and over the next 60 min the release of intracellular radioactivity into the medium was monitored. At 37 degrees C, control cells released on average 7-15% of the intracellular radioactivity as intact insulin [trichloroacetic acid (TCA)-precipitable radioactivity] and approximately 62% as TCA-soluble degradation products. In the presence of 0.1 mM chloroquine (an acidotropic agent) the release of intact insulin increased approximately twofold while degradation fell by nearly one-half. With Sephadex G-50 chromatography we found that the released radioactivity included insulin-size material that increased in the presence of chloroquine. High-performance liquid chromatography revealed that 53 (controls) and 81% (chloroquine treatment) of this latter material consisted of intact insulin. We conclude that, in addition to a major degradative pathway, cultured kidney epithelial cells exhibit a retroendocytotic pathway for insulin. Chloroquine inhibits degradation and appears to divert insulin from the degradative into the retroendocytotic pathway.(ABSTRACT TRUNCATED AT 250 WORDS)

Deletion (12)(q15q21.2)

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Trisomy 5 mosaicism in amniotic fluid with normal outcome

A case of prenatally diagnosed true mosaicism for trisomy 5 with a clinically normal outcome is presented. Trisomy 5 was detected in 23% of cells obtained by amniocentesis, but it was not detected from cells obtained by fetal blood sampling. While in this case the finding at amniocentesis did not reflect the status of the fetus, care must be exercised in reaching this conclusion in all cases.

The safety and efficacy of chorionic villus sampling for early prenatal diagnosis of cytogenetic abnormalities

Chorionic villus sampling is a method of prenatal diagnosis in the first trimester of pregnancy in which tissue for genetic study is aspirated from the developing placenta by means of a catheter inserted transcervically under the guidance of ultrasonography. In this seven-center study, we compared the safety and efficacy of chorionic villus sampling in 2278 women with those of amniocentesis at 16 weeks' gestation in 671 women. Both groups were made up primarily of well-educated private patients; they were recruited in the first trimester of pregnancy and had viable pregnancies verified by ultrasound examination. Cytogenetic diagnoses resulted from 97.8 percent of the chorionic villus sampling procedures and 99.4 percent of the amniocenteses (P less than 0.05); aneuploidy was found in 1.8 and 1.4 percent, respectively, of the cases in which diagnoses were made. Of the women who underwent chorionic villus sampling, 17 (0.8 percent) subsequently had an amniocentesis because the diagnosis was ambiguous. Two of the diagnoses of aneuploidy (one tetraploidy, one trisomy 22) were later proved to be incorrect. On the basis of pediatric examination of the infants subsequently born to the women in the sample, there were no errors in the determination of sex or the identification of the major trisomies (21, 18, and 13). The rate of combined losses due to spontaneous and missed abortions, termination of abnormal pregnancies, stillbirths, and neonatal deaths was 7.2 percent in the group that underwent chorionic villus sampling and 5.7 percent in the group that had amniocentesis. After adjustment for slight differences in gestational and maternal age, the total loss rate for the women in the chorionic villus sampling group exceeded that for the amniocentesis group by only 0.8 percentage points (80 percent confidence interval, -0.6 to 2.2). The rate of loss of chromosomally normal fetuses after chorionic villus sampling was 10.8 percent among women in whom three or four attempts were made to place the transcervical catheter, as compared with 2.9 percent in those in whom only one attempt was necessary (P less than 0.01). There were no serious maternal infections among the women in this study or among an additional 1990 women who underwent chorionic villus sampling (upper 95 percent confidence limit, 0.08 percent). We conclude that chorionic villus sampling is a safe and effective technique for the early prenatal diagnosis of cytogenetic abnormalities, but that it probably entails a slightly higher risk of procedure failure and of fetal loss than does amniocentesis.

Fatty acid content of yolk sac and embryo in hyperglycemia-induced embryopathy and effect of arachidonic acid supplementation

Using the postimplantation rat conceptus model, we analyzed with gas-liquid chromatography, the fatty acid composition in major lipid groups (phospholipids, triglycerides, nonesterified fatty acids, and cholesterol esters) of yolk sacs and embryos cultured for 48 hours under control, hyperglycemic, and arachidonic acid-supplemented hyperglycemic conditions. In all experimental conditions the yolk sacs had greater fatty acid content than the embryos in all lipid groups except in nonesterified fatty acids. The fatty acid level in embryonic nonesterified fatty acids was significantly higher (p less than 0.05) in hyperglycemia-exposed embryos than found with arachidonic acid supplementation. Total yolk sac triglycerides were greater with added glucose (p less than 0.05) than with the addition of arachidonic acid to the same medium. Oleic acid, a fatty acid associated with essential fatty acid deficiency, was increased in the embryonic phospholipids and nonesterified fatty acids of conceptuses exposed to excess glucose, as well as in the culture media of this group, compared with the control or arachidonic acid-supplemented, hyperglycemic group (p less than 0.05). The results of this study demonstrate that diabetes-related embryopathy is associated with quantitative and qualitative abnormalities in major lipid groups. Furthermore, the elevation in embryonic oleic acid level suggests that the teratogenic mechanism could be related to a deficiency in essential fatty acids. The pattern of essential fatty acid deficiency and embryopathy was preventable with arachidonic acid supplementation in this experimental model.

Prognostic significance of the human yolk sac assessed by ultrasonography

Ultrasonographic examinations were conducted between 6 and 12 weeks' gestation in 77 first-trimester pregnancies with normal fetal outcome. Each examination consisted of measurements of the secondary yolk sac diameter and the fetal crown-rump length. The yolk sac was seen in all cases, and whereas its measurements demonstrated wide biologic variability, it correlated weakly (R2 = 0.39) with gestational age as confirmed by crown-rump length measurements. Growth of the yolk sac diameter, although slight, assumed a curvilinear relationship with gestational age. Such a growth profile is best described by a second-degree polynomial regression equation. The yolk sac performs important functions for embryonic development during organogenesis and the remnant of the secondary yolk sac seen on ultrasonography is often considered to be a potential predictor of fetal outcome. Our findings indicate that the size of this remnant in pregnancies with normal karyotypes and normal fetal outcomes is extremely variable. Additionally, the yolk sac size in patients with karyotypic abnormalities and spontaneous abortion were equally variable and almost all were within the normal range. In light of these findings, the secondary yolk sac size does not appear to be a sensitive predictor of embryonic integrity and pregnancy outcome.

A reassessment of maternal serum alpha-fetoprotein in diabetic pregnancy

We assessed maternal serum alpha-fetoprotein (AFP) concentrations in 227 diabetic women who belonged to different groups of White's classification but found no difference either between the insulin-dependent and the normative population or between the former and diabetics who were not insulin-dependent. By contrast, we found in maternal blood a marked, statistically significant inverse correlation between maternal serum AFP and the concentration of glycosylated hemoglobin in maternal blood assayed within 6 weeks of each other in mid-gestation (r = -0.4, p less than 0.05), but not when glycosylated hemoglobin was determined in the first two months of pregnancy (r = 0.05). These data indicate that the decrease in maternal serum AFP found in pregnant diabetic women is related to the efficacy of diabetic control but not to the diabetic status. A correction in maternal serum AFP should therefore be applied only to values obtained for women with poor glycemic control. Decreased maternal serum AFP in poorly controlled diabetics may indicate reduced synthesis of other fetal proteins which, in turn, may correlate with fetal growth retardation and the occurrence of malformation.