Vivienne L. Souter

Background: Cesarean outcomes are rarely investigated by Asian ethnicities when examining variation among low-risk, first-time birthing parents. We analyzed a clinical birth dataset of Northwestern U.S. hospitals to evaluate disparities in unplanned cesarean births among disaggregated Asian ethnicities. Methods: This cross-sectional study used chart-abstracted birth data from 2017 through 2021. Analysis restrictions included hospitals reporting for the full timeframe, and patients who were nulliparous, term, singleton, vertex presentation, allowed to labor without a scheduled cesarean birth, and not intrapartum transfers or community births. Adjusted and unadjusted multi-level logistic regression compared the primary outcome of unplanned cesarean birth by race and Asian ethnicities. Results: A total of 40,160 births met inclusion criteria; 21.3% were Asian. Overall, the laboring cesarean rate was 23.1%, ranging from 33.9% for South Asians to 17.0% for East Asians. Compared to Whites, South Asians (OR 1.84, CI 1.66–2.04), Southeast Asians (OR 1.28, CI 1.05–1.55), and Asian unspecified (OR 1.27, CI 1.18–1.37) had significantly higher unadjusted odds of cesarean birth while East Asians had significantly lower odds (OR 0.73, CI 0.63–0.86). Odds for South Asian cesarean birth were more than doubled that of White births (aOR 2.18, CI 1.95–2.44) in the adjusted model. Conclusions: After controlling for known risk factors, South Asians had elevated odds for unplanned cesarean birth compared to other races and ethnicities, despite lower risk factor incidence. Medical systems should collect disaggregated race and ethnicity data to provide pregnancy management insights for reducing inequities in low-risk unplanned cesarean births.

Traditionally twins are classified as dizygous or fraternal and monozygous or identical (Hall Twinning, 362, 2003 and 735–743). We report a rare case of 46,XX/46,XY twins: Twin A presented with ambiguous genitalia and Twin B was a phenotypically normal male. These twins demonstrate a third, previously unreported mechanism for twinning. The twins underwent initial investigation with 17-hydroxyprogesterone and testosterone levels, pelvic ultrasound and diagnostic laparoscopy. Cytogenetic analysis was performed on peripheral blood cells and skin fibroblasts. Histological examination and Fluorescence in situ hybridization studies on touch imprints were performed on gonadal biopsies. DNA analysis using more than 6,000 DNA markers was performed on skin fibroblast samples from the twins and on peripheral blood samples from both parents. Twin A was determined to be a true hermaphrodite and Twin B an apparently normal male. Both twins had a 46,XX/46,XY chromosome complement in peripheral lymphocytes, skin fibroblasts, and gonadal biopsies. The proportion of XX to XY cells varied between the twins and the tissues evaluated. Most significantly the twins shared 100% of maternal alleles and approximately 50% of paternal alleles in DNA analysis of skin fibroblasts. The twins are chimeric and share a single genetic contribution from their mother but have two genetic contributions from their father thus supporting the existence of a third, previously unreported type of twinning.

Objectives. To investigate correlations between sonographic soft markers and biochemical markers (human chorionic gonadotrophin, α‐fetoprotein, and estriol) for Down syndrome in the second trimester of pregnancy. Methods. A total of 2183 women with apparently normal singleton fetuses who underwent second‐trimester sonography (14–22 weeks) and maternal serum biochemical testing (triple test) were identified. Seven sonographic markers were recorded: nuchal fold thickness, humerus length, femur length, renal pyelectasis, hyperechoic bowel, echogenic intracardiac focus, and choroid plexus cysts. Results. Weak negative but statistically significant correlations were observed between human chorionic gonadotropin (multiples of the median) and both femur length (multiples of the median; Spearman ρ = −0.073; P < .01) and humerus length (multiples of the median; Spearman ρ = −0.083; P < .01). No other correlations significant at the 1% level were observed between femur length (multiples of the median) or humerus length (multiples of the median) and the biochemical markers. There were no significant correlations between nuchal fold thickness and any of the 3 biochemical markers. At the 5% (P < .05) level, the median human chorionic gonadotropin level (multiples of the median) was lower when an echogenic intracardiac focus was detected. Hyperechoic bowel also tended to be associated with higher median human chorionic gonadotropin (multiples of the median) and α‐fetoprotein (multiples of the median) levels (P < .05). Conclusions. We found that sonographic and biochemical markers for trisomy 21 are largely independent in unaffected pregnancies. For accurate risk estimation, correlations in both affected and unaffected pregnancies need to be considered. No or minimal correlation between sonographic markers and serum screening tests indicates that they can be used as independent modifiers of the maternal age–specific risk for Down syndrome.

It is an accepted medical doctrine that monochorionic twins are exclusively monozygous. This doctrine is supported by two studies that assessed placental pathological features and multiple serologic markers of zygosity in a total of almost 800 monochorionic twins.^1,2 Although the possibility that monochorionic twins are not invariably monozygous has been raised previously, deficiencies in the cytogenetic and pathological characterization of these reports have cast doubt on their reliability.³ We report a case of sex-discordant monochorionic twins conceived by in vitro fertilization. The twins also had blood chimerism (the presence of cells derived from more than one genetically distinct zygote); in both twins, there was a predominance of male-derived lymphocytes, and as a result, the initial findings of zygosity studies performed on DNA extracted from the blood were consistent with monozygosity. Subsequent detailed investigation showed the twins to be dizygous. The evidence from this case is inconsistent with the doctrine that all monochorionic twins are monozygous.

We report two cases of multiple fetal anomalies detected by prenatal ultrasound and associated with subtle subtelomeric chromosomal rearrangements. The first case presented at 25 weeks of gestation with an enlarged cisterna magna and ventriculomegaly. Karyotyping of amniocytes showed a subtle terminal abnormality of chromosome 6q. Thereafter, screening of all unique chromosomal subtelomeric regions using a panel of telomere‐specific, fluorescence in situ hybridization (FISH) probes revealed an unbalanced reciprocal translocation between 6q and 17p [46,XX.ish der(6)t(6;17)(q25.3;p13)(TelVysion6q‐;TelVysion17p+)]. The second case presented at 25 weeks of gestation with tetralogy of Fallot and at 34 weeks of gestation had additional ultrasound findings of an arachnoid cyst and intrauterine growth restriction. Postnatal karyotyping of peripheral blood was performed and appeared normal. However, a cryptic deletion of the subtelomeric region of the long arm of chromosome 14 was identified when the infant's blood sample was used as a control for an oncology FISH probe. Thereafter, screening of all unique chromosomal subtelomeric regions using a panel of telomere‐specific FISH probes revealed an unbalanced reciprocal translocation of chromosomes 14q and 20p [46,XY.ish der(14)t(14;20)(q32.3;p13)(IGH‐, D14S308‐,TelVysion20p+)mat]. These two cases add to a growing number of reports of cryptic subtelomeric chromosomal rearrangements associated with congenital anomalies. This is the first report of multiple, simultaneous FISH screening of the subtelomeric regions in amniotic fluid and has demonstrated the technical feasibility of this technique in the prenatal period. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.