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Multiple Gestations
Published in Vincenzo Berghella, Maternal-Fetal Evidence Based Guidelines, 2022
Edward J. Hayes, Michelle R. Hayes
First trimester: Nuchal translucency and maternal age identify about 75–85% of trisomy 21 and 66.7% of trisomy 18 pregnancies with a 5% false-positive rate in twin gestations [34–36]. However, only nuchal translucency alone has been validated for the detection of these disorders in higher order gestations [37]. In a recent meta-analysis, first trimester combined test in twins had a pooled sensitivity of 0.893 (95% confidence interval [CI] 0.797–0.947) and a pooled specificity of 0.946 (95% CI 0.933–0.957). The performance of the test was good (summary receiver operating characteristic area under the curve: 0.817). In dichorionic twins, sensitivity and specificity were 0.862 (95% CI 0.728–0.936) and 0.952 (95% CI 0.942–0.96), respectively. In monochorionic twins, the sensitivity and specificity were 0.874% (95% CI 0.526–0.977) and 0.954% (95% CI 0.943–0.963), respectively [38]. Cell free DNA has been shown to have a pooled weighted detection rate for T21 of 98.2% (95% CI 83.2–99.8%) and false positive rate 0.05% (95 CI, 0.01–0.26%) in twins, however predictive value for T13 and T18 has yet to be determined [39].ACOG and SMFM recently endorsed cell-free DNA for the detection of T21 in twin gestations [40]. Chorionic villus sampling can be performed between 10 to 12 weeks. It has the same risks as amniocentesis in multiples [41], and has a 1.1 rate of twin-twin contamination [42].
Obstetrics: Answers
Published in Euan Kevelighan, Jeremy Gasson, Makiya Ashraf, Get Through MRCOG Part 2: Short Answer Questions, 2020
Euan Kevelighan, Jeremy Gasson, Makiya Ashraf
The combined test for Down syndrome is a combination of blood tests, maternal age and an ultrasound scan (1). The blood tests performed are pregnancy-associated plasma protein A (PAPP-A) and free beta-human chorionic gonadotrophin (1). The ultrasound determines fetal nuchal translucency, which is a measure of the fluid-filled space at the back of the fetal neck (1). The test is performed between 10 and 14 weeks’ gestation and has a detection rate of 85% for a 5% false positive rate (1).
The cardiac system: Physiology and principles of care
Published in Judy Bothamley, Maureen Boyle, Medical Conditions Affecting Pregnancy and Childbirth, 2020
Ultrasound to identify nuchal translucency should be offered to all women (NICE, 2008), and raised levels are not only associated with Down’s syndrome, but also with fetal cardiac anomalies (Ghi, et al., 2001). There is an association between increased nuchal translucency and cardiac defects both for fetuses with chromosomal abnormalities and for those without (Hyett, et al., 1999), but there is no increased risk of any particular type of heart condition (Atzei, et al., 2005). It has been suggested that effective referral of all those considered at risk (seeBox 2.6) could optimise the detection rate (Gardiner and Daubeney, 2006).
Abnormal chromosomes identification using chromosomal microarray
Published in Journal of Obstetrics and Gynaecology, 2022
Yunfang Shi, Xiaozhou Li, Duan Ju, Yan Li, Xiuling Zhang, Ying Zhang
A 34-year-old multipara at a gestational age of 18 weeks was referred to our prenatal diagnosis centre for foetal evaluation. Her first child was 3 years old with mental retardation, facial dysmorphism and developmental delay. She had a spontaneous abortion in the first trimester previously. Nuchal translucency (NT) measurement and first trimester screening were within normal limits. Amniocentesis was performed at a gestational age of 20 weeks and foetal karyotype was 46,XX,der(3), which showed an unbalanced karyotype with extra chromosomal material in the short arm of chromosome 3. SNP-array from the amniotic fluid was performed to further analyse the additional materials of unknown origin. Subsequent SNP-array identified a deletion of approximately 8.4 Mb in chromosome 3p26.3p26.1 and a duplication of 19.7 Mb in chromosome 5q34q35.3. The deletion region contained 14 OMIM genes including ITPR1. The duplication region encompasses 99 OMIM genes including NKX2-5, MSX2 and NSD1. Based on SNP-array findings, the foetal karyotype was unbalanced. The derivative chromosome 3 with loss of the segment 3p26.3pter and gain of 5q34qter replaced a normal chromosome 3 (Figure 1, Table 1).
Altered gut bacterial and metabolic signatures and their interaction in gestational diabetes mellitus
Published in Gut Microbes, 2020
Xing Wang, Hongli Liu, Yifan Li, Shuai Huang, Lan Zhang, Chiying Cao, Philip N. Baker, Chao Tong, Peng Zheng, Hongbo Qi
The study protocol was approved by the Ethics Committee of The First Affiliated Hospital of Chongqing Medical University. All participants signed a written informed consent before any procedure was performed. The diagnosis of GDM was performed based on the 75 g oral glucose tolerance test (OGTT) at 24–28th gestational weeks with following criterion:29 (i) without a history of diabetes; (ii) meeting one of the criteria: fasting blood glucose (FBG) ≥5.1 mmol/L or 1 h OGTT glucose values ≥10.0 mmol/L or 2 h OGTT glucose values ≥8.5 mmol/L. Correspondingly, the pregnant women who have normal glucose levels in OGTT were designated as healthy controls (HCs). All participants have no other complications of pregnancy, diarrhea, and other gastrointestinal symptoms when the samples were collected. And the gestation fetuses have no chromosomal and structural abnormalities. All participants did not take any antibiotics, probiotics, or prebiotics within 1 month prior to sampling. The indexes of fetal ultrasonography were acquired using the GE Voluson E8. Fetal Nuchal Translucency (NT) is measured from 11 weeks to 13 weeks and six days by transabdominally to assess the risks of Down’s syndrome and other chromosomal abnormalities. A mid sagittal section image of the fetus is required, and the magnification of fetal head and upper thorax image should occupy the whole screen. The two hyperechoic bands on the back of the fetus should be measured at the widest part of the NT. Generally, fresh stool samples were collected from participants at 7:00–12:00 AM in our hospital, and frozen at −80 C until further analysis.
Fetal hydrops – a review and a clinical approach to identifying the cause
Published in Expert Opinion on Orphan Drugs, 2020
Esther Dempsey, Tessa Homfray, John M Simpson, Steve Jeffery, Sahar Mansour, Pia Ostergaard
Fetal hydrops, the abnormal accumulation of fluid in two or more fetal compartments, affects approximately 1 in 1,700 pregnancies [1]. Fetal hydrops can occur at any point in a pregnancy. In the first trimester the first sign is typically a raised nuchal translucency on fetal ultrasound. The nuchal translucency is the region of the back of the fetal neck which increases in size when there is subcutaneous edema or enlarged jugular lymphatic sacs (Figure 1). When there are two or more of: pericardial effusion, pleural effusion, ascites or generalized skin edema, fetal hydrops can be diagnosed. (Figure 2). Placental thickening/edema and polyhydramnios (increased amniotic fluid levels) can be seen in cases of fetal hydrops, but are not critical features for the diagnosis. The identification of fetal hydrops should prompt urgent referral to a center with maternal-fetal medicine expertise. Ultrasound imaging (including Doppler studies), as well as a thorough maternal obstetric and family history, can help to make a diagnosis, guide treatment and estimate prognosis.