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- Sperling, L., et al.
(författare)
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Detection of chromosomal abnormalities, congenital abnormalities and transfusion syndrome in twins
- 2007
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Ingår i: Ultrasound in Obstetrics & Gynecology. - : Wiley. - 1469-0705 .- 0960-7692. ; 29:5, s. 517-526
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Tidskriftsartikel (refereegranskat)abstract
- Objective To evaluate the outcome of screening for structural malformations in twins and the outcome of screening for twin-twin transfusion syndrome (TTTS) among monochorionic twins through a number of ultrasound scans from 12 weeks' gestation. Methods Enrolled into this prospective multicenter observational study were women with twin pregnancies diagnosed before 14 + 6 gestational weeks. The monochorionic pregnancies were scanned every second week until 23 weeks in order to rule out early TTTS. All pregnancies had an anomaly scan in week 19 and fetal echocardiography in week 21 that was performed by specialists in fetal echocardiography. Zygosity was determined by DNA analysis in all twin pairs with the same sex. Results Among the 495 pregnancies the prenatal detection rate for severe structural abnormalities including chromosomal aneuploidies was 83% by the combination of a first-trimester nuchal translucency scan and the anomaly scan in week 19. The incidence of severe structural abnormalities was 2.6% and two-thirds of these anomalies were cardiac. There was no significant difference between the incidence in monozygotic and dizygotic twins, nor between twins conceived naturally or those conceived by assisted reproduction. The incidence of TTTS was 23% from 12 weeks until delivery, and all those monochorionic twin pregnancies that miscarried had signs of TTTS. Conclusion Twin pregnancies have an increased risk of congenital malformations and one out of four monochorionic pregnancies develops TTTS. Ultrasound screening to assess chorionicity and follow-up of monochorionic pregnancies to detect signs of TTTS, as well as malformation screening, are therefore essential in the antenatal care of twin pregnancies. Copyright (c) 2007 IS UOG. Published by John Wiley & Sons, Ltd.
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| 2. |
- Sperling, L, et al.
(författare)
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How to identify twins at low risk of spontaneous preterm delivery
- 2005
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Ingår i: Ultrasound in Obstetrics & Gynecology. - : Wiley. - 1469-0705 .- 0960-7692. ; 26:2, s. 138-144
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Tidskriftsartikel (refereegranskat)abstract
- Objective The aim of this study was to evaluate transvaginal sonograpbic assessment of cervical length at 23 weeks as a screening test for spontaneous preterm delivery in order to define a cut-off value that could be used to select twin pregnancies at low risk of spontaneous preterm delivery. Methods In a prospective multicenter study of 383 twin pregnancies included before 14 + 6 weeks a cervical scan with measurement of the cervical length was performed at 23 weeks' gestation. The results were blinded for the clinicians if the cervical length was >= 15 mm. The rates of spontaneous delivery at different cut-off levels of cervical length were determined. Results Eighty-nine percent of the twins had dichorionic placentation and 58% were conceived after assisted reproduction. The rate of spontaneous preterm delivery was 2.3% (1.5% for dichorionic (DC) and 9.1% for (MC) monochorionic twins) before 28 weeks and 18.5% (17.1% for DC and 29.5% for MC twins) before 35 weeks. The screen-positive rate was 5% for a cervical length <= 20, 7-8% at <= 25, 16-17% at <= 30 and 34-48% at <= 35mm depending on chorionicity. The false-negative rate (1 - negative predictive value) ranged from 1.2% at 28 weeks to 18.6% at 35 weeks for all twins. Receiver-operating characteristics curves showed that the sensitivity increased with declining gestation I age with cut-off levels of highest accuracy at 21 mm for 28 weeks and 29 mm for 33 weeks. Conclusions Cervical length measurement at 23 weeks of gestation is a good screening test for predicting twins at low risk of preterm and very preterm delivery, especially in DC twins. The present results suggest that a cut-off of 25 mm should be recommended.
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| 3. |
- Sperling, L., et al.
(författare)
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Naturally conceived twins with monochorionic placentation have the highest risk of fetal loss
- 2006
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Ingår i: Ultrasound in Obstetrics & Gynecology. - : Wiley. - 1469-0705 .- 0960-7692. ; 28:5, s. 644-652
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Tidskriftsartikel (refereegranskat)abstract
- Objective The aim of this study was to estimate the rate of fetal loss in dichorionic (DC) and monochorionic (MC) twin pregnancies stratified according to zygosity and method of conception. Methods In a prospective multicenter observational study women with a twin pregnancy bad an ultrasound scan before 14 + 6 weeks' gestation in order to determine chorionicity. The fetal loss rate, the perinatal, neonatal and infant mortality rates and the frequency of very preterm labor were estimated for the different types of twin. Results Among the 495 pregnancies (421 DC and 74 MC) 229 (46%) were conceived naturally and 266 (54%) by assisted reproduction (AR). Outcome data for 945 liveborn babies were obtained. The spontaneous miscarriage rate before 24 weeks' gestation was 10.9% (7164) among naturally conceived MC compared to 3.0% (51165) for naturally conceived DC twins (P < 0.05). For twins conceived by AR the corresponding figures were 0% (0/10) and 0.4% (1/256). The odds ratio (OR) for very preterm birth - before 28 weeks'gestation - was 4.2 for MC twins compared to DC twins. The relative risk of fetal loss or death among DC twins was 20% of the risk for MC twins. Conclusion The risk of fetal loss, very preterm delivery and neonatal/infant death is significantly higher among twins with MC compared to DC placentation. Twins conceived by AR have a much lower risk of MC placentation. The risk of losing one or both twins seems higher among naturally conceived twins compared to twins conceived by AR, despite the fact that the maternal age was higher among the mothers of the AR twins. Copyright (c) 2006 ISUOG. Published by John Wiley & Sons, Ltd.
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