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ORIGINAL RESEARCH
First-Trimester Sonographic Prediction of Obstetric and Neonatal Outcomes in Monochorionic Diamniotic Twin Pregnancies M. Baraa Allaf, MD, Anthony M. Vintzileos, MD, Martin R. Chavez, MD, Joseph A. Wax, MD, Samadh F. Ravangard, DO, Reinaldo Figueroa, MD, Adam Borgida, MD, Amir Shamshirsaz, MD, Glenn Markenson, MD, Sarah Davis, MD, Rebecca Habenicht, MD, Sina Haeri, MD, Ali Ozhand, MD, PhD, Jeffery Johnson, MD, Haleh Sangi-Haghpeykar, PhD, Melissa Spiel, DO, Rodrigo Ruano, MD, PhD, Marjorie Meyer, MD, Michael A. Belfort, MD, PhD, Paul Ogburn, MD, Winston A. Campbell, MD, Alireza A. Shamshirsaz, MD Received April 11, 2013, from the Department of Obstetrics and Gynecology, Stony Brook University, Stony Brook, New York USA (M.B.A., R.F., P.O.); Department of Obstetrics and Gynecology, Winthrop University Hospital, Mineola, New York USA (M.B.A., A.M.V., M.R.C.); Department of Obstetrics and Gynecology, Maine Medical Center, Portland, Maine USA (J.A.W.); Department of Obstetrics and Gynecology, University of Connecticut, Farmington, Connecticut USA (S.F.R., M.S., W.A.C., A.A.S.); Department of Obstetrics and Gynecology, Hartford Hospital, Hartford, Connecticut USA (A.B., A.A.S.); Department of Obstetrics and Gynecology, George Washington University, Washington, DC USA (A.S.); Department of Obstetrics and Gynecology, Baystate Medical Center, Springfield, Massachusetts USA (G.M.); Department of Obstetrics and Gynecology, University of Vermont, Burlington, Vermont USA (S.D., M.M.); Department of Obstetrics and Gynecology, Dartmouth-Hitchcock Medical Center, Bedford, New Hampshire USA (R.H., J.J.); Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, Texas USA (S.H., H.S.-H., R.R., M.A.B., A.A.S.); and Department of Preventive Medicine, University of Southern California, Los Angeles, California USA (A.O.). Revision requested April 22, 2013. Revised manuscript accepted for publication May 20, 2013. This study was presented in part as an oral presentation at the 2012 American Institute of Ultrasound in Medicine Annual Convention; March 29–April 1, 2012; Phoenix, Arizona; and as a poster at the 33rd Annual Meeting of the Society for Maternal-Fetal Medicine, February 11–16, 2013; San Francisco, California. Address correspondence to Alireza A. Shamshirsaz, MD, Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, Baylor College of Medicine, Pavilion for Women–Texas Children’s Fetal Center, 6651 Main St, Suite F1020, Houston, TX 77030 USA. E-mail: [email protected], [email protected]
Objectives—The purpose of this study was to investigate whether discordant nuchal translucency and crown-rump length measurements in monochorionic diamniotic twins are predictive of adverse obstetric and neonatal outcomes. Methods—We conducted a multicenter retrospective cohort study including all monochorionic diamniotic twin pregnancies with two live fetuses at the 11-week to 13-week 6-day sonographic examination who had serial follow-up sonography until delivery. Isolated nuchal translucency, crown-rump length, and combined discordances were correlated with adverse obstetric outcomes, individually and in composite, including the occurrence of 1 or more of the following in either fetus: intrauterine growth restriction (IUGR), twin-twin transfusion syndrome (TTTS), intrauterine fetal death (IUFD), growth discordance (≥20%), and preterm birth before 28 weeks’ gestation. Correlations with adverse composite neonatal outcomes were also studied. A receiver operating characteristic curve analysis and a logistic regression analysis with a generalized estimating equation were conducted. Results—Fifty-four of the 177 pregnancies included (31%) had an adverse composite obstetric outcome, with TTTS in 19 (11%), IUGR in 21 (12%), discordant growth in 14 (8%), IUFD in 14 (8%), and preterm birth before 28 weeks in 10 (6%). Of the 254 neonates included in the study, 69 (27%) were complicated by adverse composite neonatal outcomes, with respiratory distress syndrome being the most common (n = 59 [23%]). The areas under the curve for the combined discordances to predict composite obstetric and neonatal outcomes were 0.62 (95% confidence interval, 0.52–0.72), and 0.54 (95% confidence interval, 0.46–0.61), respectively. Conclusions—In our population, nuchal translucency, crown-rump length, and combined discordances in monochorionic diamniotic twin pregnancies were not predictive of adverse composite obstetric and neonatal outcomes. Key Words—crown-rump length; monochorionic twins; nuchal translucency; obstetric ultrasound; twin-twin transfusion syndrome
Abbreviations AUC, area under the curve; CI, confidence interval; IUFD, intrauterine fetal death; IUGR, intrauterine growth restriction; RDS, respiratory distress syndrome; TTTS, twin-twin transfusion syndrome
doi:10.7863/ultra.33.1.135
A
dvances in assisted reproductive technologies along with their increased use have led to rising rates of twin gestations in the United States.1 Monochorionic twins constitute up to one-third of all twin gestations.1 Compared to their dichorionic
©2014 by the American Institute of Ultrasound in Medicine | J Ultrasound Med 2014; 33:135–140 | 0278-4297 | www.aium.org
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Allaf et al—Prediction of Outcomes in Monochorionic Diamniotic Twin Pregnancies
counterparts, monochorionic diamniotic twins are at increased risk for perinatal morbidity, including intrauterine fetal death (IUFD), fetal loss before 24 weeks, intrauterine growth restriction (IUGR), and twin-twin transfusion syndrome (TTTS).2–4 Indeed, TTTS affects 1 of 10 monochorionic diamniotic twin pregnancies between 16 and 26 weeks and is the most important cause of fetal loss.2,3 Accurate prediction and early detection of these complications may offer the opportunity for timely intervention, which may improve outcomes. Conflicting results have been reported about the use of nuchal translucency and crown-rump length discordances as early predictors of adverse obstetric outcomes.5,6 Furthermore, data are limited regarding the relationship of nuchal translucency and crown-rump length discordances with adverse neonatal outcomes. Consequently, the aim of this study was to test the hypothesis that discordant nuchal translucency, crownrump length, and combined (nuchal translucency and crown-rump length) measurements in monochorionic diamniotic twins at the time of aneuploidy screening are predictive of adverse obstetric and neonatal outcomes.
Materials and Methods This multicenter retrospective cohort study was conducted at 9 regional perinatal centers in the United States. Approval for this study was obtained from the local Institutional Review Board at each participating site before data collection. The electronic obstetric ultrasound database of each institution was queried to identify all monochorionic diamniotic twin pregnancies with two live fetuses presenting at the 11-week to 13-week 6-day sonographic examination between January 2007 and June 2011. All sonographic examinations (including nuchal translucency and crown-rump length measurements) were performed by maternal-fetal medicine specialists or registered diagnostic medical sonographers accredited by the Nuchal Translucency Review Program or the Fetal Medicine Foundation to perform first-trimester screening. In addition, all sites had accreditation by the American Institute of Ultrasound in Medicine at the time of this study. Gestational age was determined by the last menstrual period and confirmed by the first-trimester crown-rump length measurement of the larger twin. Monochorionicity was confirmed by review of the first-trimester sonographic reports using previously published criteria,7,8 verification of identical sexes, and review of the placental pathologic reports.
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All monochorionic diamniotic twin pregnancies included were monitored by serial sonographic evaluations of growth, amniotic fluid volume measurement, and Doppler interrogation of the fetal vessels starting at 16 to 18 weeks’ gestation and at least every 2 to 4 weeks thereafter until delivery. We excluded cases with known chromosomal abnormalities, major congenital malformations, and single or double IUFD at time of the first-trimester examination. Pregnancies referred at later gestations or with no follow-up sonographic examinations were also excluded from the study. The intertwin discordances in nuchal translucency and crown-rump length were calculated as the differences in the measurements between the two fetuses, expressed as a percentage of the larger measurement. Maternal and neonatal characteristics, antenatal courses, and outcomes were collected from review of their medical records. An adverse composite obstetric outcome included the occurrence of 1 or more of the following in either fetus: IUGR, defined as estimated fetal weight below the 10th percentile,9,10 TTTS according to the classification of Quintero et al,11 IUFD, growth discordance of 20% or greater at any sonographic examination between 16 and 28 weeks’ gestation, and preterm birth as defined by delivery at 28 weeks or earlier. An adverse composite neonatal outcome included the occurrence of 1 or more of the following: respiratory distress syndrome (RDS), any stage of intraventricular hemorrhage, 5-minute Apgar score less than 7, necrotizing enterocolitis, culture-proven earlyonset sepsis, and neonatal death. The analysis plan included an evaluation of the nuchal translucency discordance alone first, followed by an evaluation of the crown-rump length discordance alone, and a final examination of the combined (nuchal translucency and crown-rump length) discordances to predict an adverse composite obstetric or neonatal outcome. The same analysis regimen was performed separately to assess the prediction of TTTS as a single complication. Logistic regression and receiver operating characteristic curve analyses were used to estimate the area under the curve (AUC). To adjust for clustering in the analysis of neonatal and live birth outcomes, a logistic regression analysis was performed via a generalized estimating equation model using SAS software (SAS Institute Inc, Cary, NC). We also stratified our data on the basis of previously published literature suggesting that an intertwin nuchal translucency discordance of 20% or greater may be of use to predict adverse outcomes.5 Therefore, χ2 analyses were used to compare nuchal translucency discordance for twin pairs with discordance of 20% or greater versus those with discordance less than 20%. P < .05 was considered significant.
J Ultrasound Med 2014; 33:135–140
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Allaf et al—Prediction of Outcomes in Monochorionic Diamniotic Twin Pregnancies
Results A total of 177 monochorionic diamniotic twin pregnancies were evaluated for obstetric outcomes. The neonatal outcomes of 254 neonates were included in the analysis. We excluded 81 neonates for incomplete neonatal data and 19 fetuses (from 14 pregnancies) for IUFD after the first-trimester sonographic examination. The baseline maternal characteristics are presented in Table 1. Other characteristics included a mean gestational age ± SD at the time of first-trimester evaluation of 12.4 ± 0.6 weeks, a mean nuchal translucency measurement of 1.5 ± 0.58 mm, a mean crown-rump length measurement of 62.1 ± 9.5 mm, median nuchal translucency discordance of 11.1% (range, 0%–89.2%), and median crown-rump length discordance of 9.2% (range, 0%–57.3%). The adverse obstetric outcomes are presented in Table 2. Of the 54 pregnancies complicated by an adverse composite obstetric outcome (31%), 19 (11 %) were due to TTTS and 21 (12 %) were due to IUGR. Predictions of adverse composite obstetric outcomes provided by the discordances in nuchal translucency, crown-rump length, and the combination, expressed as AUCs (Figure 1), were 0.59 (95% confidence interval [CI], 0.50–0.69), 0.57 (95% CI, 0.48–0.66), and 0.62 (95% CI, 0.52–0.72), respectively. The AUCs for discordances in nuchal translucency, crown-rump length, and the combination for predicting subsequent TTTS development as a single complication (Figure 2) were 0.52 (95 CI, 0.39–0.65), 0.57 (95%, CI 0.44–0.70), and 0.56 (95% CI, 0.43–0.69). For all other adverse obstetric outcomes (IUGR, discordant growth, IUFD, and preterm birth), the AUCs for the discordances in nuchal transluTable 1. Maternal Characteristics (n = 177) Characteristic Maternal age, y Gestational age at delivery, wk Race, n (%) White Black Hispanic Asian Other Mode of conception, n (%) Assisted reproductive technology Spontaneous Mode of delivery, n (%) Cesarean section Vaginal delivery
Value 34 ± 3.9 34.5 ± 3.9 132 (74.5) 15 (8.4) 17 (10) 9 (5) 4 (2.2) 48 (27) 129 (73) 154 (87) 23 (13)
Data are presented as mean ± SD where applicable.
J Ultrasound Med 2014; 33:135–140
cency, crown-rump length, and the combination ranged from 0.48 to 0.64 (Figure 3). Table 3 shows the incidence of each of the adverse neonatal outcomes as well as the composite outcome. Overall, a composite measure of an adverse neonatal outcome was present in 69 of all twins (27%). Respiratory distress syndrome was the most common neonatal complication (59 [23%]), followed by intraventricular hemorrhage (14 [5.5%]). Receiver operating characteristic curve analyses of nuchal translucency, crown-rump length, and combined discordances for the prediction of adverse composite neonatal outcomes yielded AUCs (Figure 4) of 0.54 (95% CI, 0.46–0.61), 0.49 (95% CI, 041–0.57), and 0.54 (95% CI, 0.46–0.61), respectively. We further stratified and analyzed our data on the basis of complications independent of prematurity (TTTS, IUGR, discordant growth ≥20%, and IUFD) versus those that are dependent on prematurity (preterm delivery ≥28 weeks, RDS, intraventricular hemorrhage, Apgar scores
ORIGINAL RESEARCH
First-Trimester Sonographic Prediction of Obstetric and Neonatal Outcomes in Monochorionic Diamniotic Twin Pregnancies M. Baraa Allaf, MD, Anthony M. Vintzileos, MD, Martin R. Chavez, MD, Joseph A. Wax, MD, Samadh F. Ravangard, DO, Reinaldo Figueroa, MD, Adam Borgida, MD, Amir Shamshirsaz, MD, Glenn Markenson, MD, Sarah Davis, MD, Rebecca Habenicht, MD, Sina Haeri, MD, Ali Ozhand, MD, PhD, Jeffery Johnson, MD, Haleh Sangi-Haghpeykar, PhD, Melissa Spiel, DO, Rodrigo Ruano, MD, PhD, Marjorie Meyer, MD, Michael A. Belfort, MD, PhD, Paul Ogburn, MD, Winston A. Campbell, MD, Alireza A. Shamshirsaz, MD Received April 11, 2013, from the Department of Obstetrics and Gynecology, Stony Brook University, Stony Brook, New York USA (M.B.A., R.F., P.O.); Department of Obstetrics and Gynecology, Winthrop University Hospital, Mineola, New York USA (M.B.A., A.M.V., M.R.C.); Department of Obstetrics and Gynecology, Maine Medical Center, Portland, Maine USA (J.A.W.); Department of Obstetrics and Gynecology, University of Connecticut, Farmington, Connecticut USA (S.F.R., M.S., W.A.C., A.A.S.); Department of Obstetrics and Gynecology, Hartford Hospital, Hartford, Connecticut USA (A.B., A.A.S.); Department of Obstetrics and Gynecology, George Washington University, Washington, DC USA (A.S.); Department of Obstetrics and Gynecology, Baystate Medical Center, Springfield, Massachusetts USA (G.M.); Department of Obstetrics and Gynecology, University of Vermont, Burlington, Vermont USA (S.D., M.M.); Department of Obstetrics and Gynecology, Dartmouth-Hitchcock Medical Center, Bedford, New Hampshire USA (R.H., J.J.); Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, Texas USA (S.H., H.S.-H., R.R., M.A.B., A.A.S.); and Department of Preventive Medicine, University of Southern California, Los Angeles, California USA (A.O.). Revision requested April 22, 2013. Revised manuscript accepted for publication May 20, 2013. This study was presented in part as an oral presentation at the 2012 American Institute of Ultrasound in Medicine Annual Convention; March 29–April 1, 2012; Phoenix, Arizona; and as a poster at the 33rd Annual Meeting of the Society for Maternal-Fetal Medicine, February 11–16, 2013; San Francisco, California. Address correspondence to Alireza A. Shamshirsaz, MD, Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, Baylor College of Medicine, Pavilion for Women–Texas Children’s Fetal Center, 6651 Main St, Suite F1020, Houston, TX 77030 USA. E-mail: [email protected], [email protected]
Objectives—The purpose of this study was to investigate whether discordant nuchal translucency and crown-rump length measurements in monochorionic diamniotic twins are predictive of adverse obstetric and neonatal outcomes. Methods—We conducted a multicenter retrospective cohort study including all monochorionic diamniotic twin pregnancies with two live fetuses at the 11-week to 13-week 6-day sonographic examination who had serial follow-up sonography until delivery. Isolated nuchal translucency, crown-rump length, and combined discordances were correlated with adverse obstetric outcomes, individually and in composite, including the occurrence of 1 or more of the following in either fetus: intrauterine growth restriction (IUGR), twin-twin transfusion syndrome (TTTS), intrauterine fetal death (IUFD), growth discordance (≥20%), and preterm birth before 28 weeks’ gestation. Correlations with adverse composite neonatal outcomes were also studied. A receiver operating characteristic curve analysis and a logistic regression analysis with a generalized estimating equation were conducted. Results—Fifty-four of the 177 pregnancies included (31%) had an adverse composite obstetric outcome, with TTTS in 19 (11%), IUGR in 21 (12%), discordant growth in 14 (8%), IUFD in 14 (8%), and preterm birth before 28 weeks in 10 (6%). Of the 254 neonates included in the study, 69 (27%) were complicated by adverse composite neonatal outcomes, with respiratory distress syndrome being the most common (n = 59 [23%]). The areas under the curve for the combined discordances to predict composite obstetric and neonatal outcomes were 0.62 (95% confidence interval, 0.52–0.72), and 0.54 (95% confidence interval, 0.46–0.61), respectively. Conclusions—In our population, nuchal translucency, crown-rump length, and combined discordances in monochorionic diamniotic twin pregnancies were not predictive of adverse composite obstetric and neonatal outcomes. Key Words—crown-rump length; monochorionic twins; nuchal translucency; obstetric ultrasound; twin-twin transfusion syndrome
Abbreviations AUC, area under the curve; CI, confidence interval; IUFD, intrauterine fetal death; IUGR, intrauterine growth restriction; RDS, respiratory distress syndrome; TTTS, twin-twin transfusion syndrome
doi:10.7863/ultra.33.1.135
A
dvances in assisted reproductive technologies along with their increased use have led to rising rates of twin gestations in the United States.1 Monochorionic twins constitute up to one-third of all twin gestations.1 Compared to their dichorionic
©2014 by the American Institute of Ultrasound in Medicine | J Ultrasound Med 2014; 33:135–140 | 0278-4297 | www.aium.org
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Allaf et al—Prediction of Outcomes in Monochorionic Diamniotic Twin Pregnancies
counterparts, monochorionic diamniotic twins are at increased risk for perinatal morbidity, including intrauterine fetal death (IUFD), fetal loss before 24 weeks, intrauterine growth restriction (IUGR), and twin-twin transfusion syndrome (TTTS).2–4 Indeed, TTTS affects 1 of 10 monochorionic diamniotic twin pregnancies between 16 and 26 weeks and is the most important cause of fetal loss.2,3 Accurate prediction and early detection of these complications may offer the opportunity for timely intervention, which may improve outcomes. Conflicting results have been reported about the use of nuchal translucency and crown-rump length discordances as early predictors of adverse obstetric outcomes.5,6 Furthermore, data are limited regarding the relationship of nuchal translucency and crown-rump length discordances with adverse neonatal outcomes. Consequently, the aim of this study was to test the hypothesis that discordant nuchal translucency, crownrump length, and combined (nuchal translucency and crown-rump length) measurements in monochorionic diamniotic twins at the time of aneuploidy screening are predictive of adverse obstetric and neonatal outcomes.
Materials and Methods This multicenter retrospective cohort study was conducted at 9 regional perinatal centers in the United States. Approval for this study was obtained from the local Institutional Review Board at each participating site before data collection. The electronic obstetric ultrasound database of each institution was queried to identify all monochorionic diamniotic twin pregnancies with two live fetuses presenting at the 11-week to 13-week 6-day sonographic examination between January 2007 and June 2011. All sonographic examinations (including nuchal translucency and crown-rump length measurements) were performed by maternal-fetal medicine specialists or registered diagnostic medical sonographers accredited by the Nuchal Translucency Review Program or the Fetal Medicine Foundation to perform first-trimester screening. In addition, all sites had accreditation by the American Institute of Ultrasound in Medicine at the time of this study. Gestational age was determined by the last menstrual period and confirmed by the first-trimester crown-rump length measurement of the larger twin. Monochorionicity was confirmed by review of the first-trimester sonographic reports using previously published criteria,7,8 verification of identical sexes, and review of the placental pathologic reports.
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All monochorionic diamniotic twin pregnancies included were monitored by serial sonographic evaluations of growth, amniotic fluid volume measurement, and Doppler interrogation of the fetal vessels starting at 16 to 18 weeks’ gestation and at least every 2 to 4 weeks thereafter until delivery. We excluded cases with known chromosomal abnormalities, major congenital malformations, and single or double IUFD at time of the first-trimester examination. Pregnancies referred at later gestations or with no follow-up sonographic examinations were also excluded from the study. The intertwin discordances in nuchal translucency and crown-rump length were calculated as the differences in the measurements between the two fetuses, expressed as a percentage of the larger measurement. Maternal and neonatal characteristics, antenatal courses, and outcomes were collected from review of their medical records. An adverse composite obstetric outcome included the occurrence of 1 or more of the following in either fetus: IUGR, defined as estimated fetal weight below the 10th percentile,9,10 TTTS according to the classification of Quintero et al,11 IUFD, growth discordance of 20% or greater at any sonographic examination between 16 and 28 weeks’ gestation, and preterm birth as defined by delivery at 28 weeks or earlier. An adverse composite neonatal outcome included the occurrence of 1 or more of the following: respiratory distress syndrome (RDS), any stage of intraventricular hemorrhage, 5-minute Apgar score less than 7, necrotizing enterocolitis, culture-proven earlyonset sepsis, and neonatal death. The analysis plan included an evaluation of the nuchal translucency discordance alone first, followed by an evaluation of the crown-rump length discordance alone, and a final examination of the combined (nuchal translucency and crown-rump length) discordances to predict an adverse composite obstetric or neonatal outcome. The same analysis regimen was performed separately to assess the prediction of TTTS as a single complication. Logistic regression and receiver operating characteristic curve analyses were used to estimate the area under the curve (AUC). To adjust for clustering in the analysis of neonatal and live birth outcomes, a logistic regression analysis was performed via a generalized estimating equation model using SAS software (SAS Institute Inc, Cary, NC). We also stratified our data on the basis of previously published literature suggesting that an intertwin nuchal translucency discordance of 20% or greater may be of use to predict adverse outcomes.5 Therefore, χ2 analyses were used to compare nuchal translucency discordance for twin pairs with discordance of 20% or greater versus those with discordance less than 20%. P < .05 was considered significant.
J Ultrasound Med 2014; 33:135–140
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Allaf et al—Prediction of Outcomes in Monochorionic Diamniotic Twin Pregnancies
Results A total of 177 monochorionic diamniotic twin pregnancies were evaluated for obstetric outcomes. The neonatal outcomes of 254 neonates were included in the analysis. We excluded 81 neonates for incomplete neonatal data and 19 fetuses (from 14 pregnancies) for IUFD after the first-trimester sonographic examination. The baseline maternal characteristics are presented in Table 1. Other characteristics included a mean gestational age ± SD at the time of first-trimester evaluation of 12.4 ± 0.6 weeks, a mean nuchal translucency measurement of 1.5 ± 0.58 mm, a mean crown-rump length measurement of 62.1 ± 9.5 mm, median nuchal translucency discordance of 11.1% (range, 0%–89.2%), and median crown-rump length discordance of 9.2% (range, 0%–57.3%). The adverse obstetric outcomes are presented in Table 2. Of the 54 pregnancies complicated by an adverse composite obstetric outcome (31%), 19 (11 %) were due to TTTS and 21 (12 %) were due to IUGR. Predictions of adverse composite obstetric outcomes provided by the discordances in nuchal translucency, crown-rump length, and the combination, expressed as AUCs (Figure 1), were 0.59 (95% confidence interval [CI], 0.50–0.69), 0.57 (95% CI, 0.48–0.66), and 0.62 (95% CI, 0.52–0.72), respectively. The AUCs for discordances in nuchal translucency, crown-rump length, and the combination for predicting subsequent TTTS development as a single complication (Figure 2) were 0.52 (95 CI, 0.39–0.65), 0.57 (95%, CI 0.44–0.70), and 0.56 (95% CI, 0.43–0.69). For all other adverse obstetric outcomes (IUGR, discordant growth, IUFD, and preterm birth), the AUCs for the discordances in nuchal transluTable 1. Maternal Characteristics (n = 177) Characteristic Maternal age, y Gestational age at delivery, wk Race, n (%) White Black Hispanic Asian Other Mode of conception, n (%) Assisted reproductive technology Spontaneous Mode of delivery, n (%) Cesarean section Vaginal delivery
Value 34 ± 3.9 34.5 ± 3.9 132 (74.5) 15 (8.4) 17 (10) 9 (5) 4 (2.2) 48 (27) 129 (73) 154 (87) 23 (13)
Data are presented as mean ± SD where applicable.
J Ultrasound Med 2014; 33:135–140
cency, crown-rump length, and the combination ranged from 0.48 to 0.64 (Figure 3). Table 3 shows the incidence of each of the adverse neonatal outcomes as well as the composite outcome. Overall, a composite measure of an adverse neonatal outcome was present in 69 of all twins (27%). Respiratory distress syndrome was the most common neonatal complication (59 [23%]), followed by intraventricular hemorrhage (14 [5.5%]). Receiver operating characteristic curve analyses of nuchal translucency, crown-rump length, and combined discordances for the prediction of adverse composite neonatal outcomes yielded AUCs (Figure 4) of 0.54 (95% CI, 0.46–0.61), 0.49 (95% CI, 041–0.57), and 0.54 (95% CI, 0.46–0.61), respectively. We further stratified and analyzed our data on the basis of complications independent of prematurity (TTTS, IUGR, discordant growth ≥20%, and IUFD) versus those that are dependent on prematurity (preterm delivery ≥28 weeks, RDS, intraventricular hemorrhage, Apgar scores
