Discordance of First-Trimester Crown-Rump Length Is a Predictor of Adverse Outcomes in Structurally Normal Euploid Dichorionic Twins

Abstract

Objective. The purpose of this study was to determine the association between discordant crownrump length (CRL) measurements in structurally normal euploid dichorionic twins and adverse pregnancy outcomes. Methods. This retrospective cohort study included women with dichorionic twins who underwent chorionic villus sampling and delivered in our facility from January 2000 to September 2007. Only pregnancies with viable twin fetuses and normal karyotypes were included. The association between CRL discordance, defined as a CRL discrepancy of 9% or greater, and adverse pregnancy outcomes was evaluated. Results. Seventy-eight women met inclusion criteria and included 24 discordant twins (group 1) and 54 concordant twins (group 2). Maternal ages were similar: mean ± SD, 38.2 ± 3.1 years in group 1 versus 39.2 ± 3.9 years in group 2 (P = not significant). The median gestational ages at delivery were 35.6 ± 3.1 weeks in group 1 and 37.3 ± 2.0 weeks in group 2 (P < .01). At least 1 major complication occurred in 19 women (79%) in group 1 and 25 (46%) in group 2 (P = .01). Group 1 had significantly more major complications overall (P = .0008). Preterm premature rupture of membranes occurred in 10 women (42%) in group 1 and 6 (11%) in group 2 (P = .005). Delivery before 37 weeks' gestation occurred in 19 of 24 women (79%) in group 1 and 24 of 54 (44%) in group 2 (P = .006). There was a significant difference for younger gestational age at delivery in the discordant group (P < .01). Conclusions. Our data suggest that there is an increased risk of adverse pregnancy outcomes in chromosomally normal dichorionic twins with first-trimester discordant CRL measurements. These results may be clinically useful for counseling, management, and antenatal surveillance. Key words: crown-rump length; dichorionic; discordance; prenatal diagnosis; twin. Whether CRL dissimilarity specifically in chromosomally euploid and structurally normal twins is associated with adverse perinatal outcomes is unknown. Tai and Grobman 4 reported an increased incidence of intrauterine growth restriction in at least one of the twin pair with first-trimester discordance above the 85th percentile and significantly increased composite perinatal morbidity. However, the fetal karyotype and stratification of outcome Received March 8, 2010, from the Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology (R.F., J.W., I.S., M.J.K., S.R.), and Division of Biostatistics (J.M.M.), Cedars-Sinai

Can discordance in CRL at the first trimester predict birth weight discordance in twin pregnancies?

“…Achiron and Blickstein [1] were the fi rst to report a case of invitro fertilization (IVF) twin pregnancy in which birth weight discordance was initially preceded by fi rst-trimester CRL discordance. Moreover, several authors reported an association between CRL discordance in twin pregnancies and adverse pregnancy outcomes, such as subsequent fetal loss, birth weight discordance, and premature deliveries [5,8,10] . Although several studies assumed that CRL discordance in MC twins can be attributed to early development of TTTS [19,20] , others failed to demonstrate it.…”

“…Other studies raised the possibility of an association between NT and birth weight, based on the hypothesis that hyperglycemia may cause both measurements to be increased with the proposed mechanisms of enhancement of microvascular permeability that increases NT and elevation of fetal insulin levels that increases birth weight [3,14,15,22] . A number of studies described a correlation between CRL discordance and birth weight discordance in twin pregnancies [1,4,8,10] . Such a correlation was suggested in both dichorionic (DC) and monochorionic (MC) pregnancies [8] , only in DC twins [4] , and was not found by others [2] .…”

First-trimester Ultrasound and Aneuploidy Screening in Multifetal Pregnancies

“…Studies evaluating whether size discordance in the first trimester, based on CRL, is associated with adverse perinatal outcomes, such as preterm birth and growth restriction, have reported conflicting findings. [22][23][24][25][26][27] Variations in the studies, such as different thresholds for CRL discordance and inclusion of fetuses with chromosomal and structural abnormalities as well as monochorionic twins, may affect the study conclusions. The STORK trial, which is the largest study on CRL discordance to date, evaluated the outcomes of 2155 twin pregnancies.…”

Intertwin estimated fetal weight or crown rump length discordance and adverse perinatal outcome

“…A series of previous studies have indicated a correlation between intertwin CRL discrepancy in first trimester and poor perinatal outcome (intrauterine death, perinatal mortality, preterm birth) [30,[35][36][37][38][39][40][41][42][43][44][45][46][47][48] (Table 2). Nevertheless, most of them failed to verify the predictive value of CRL discrepancy for adverse outcome.…”

“…135 Retrospective MC Not included 5-20% Shahshahan [43] 118 Prospective DC Not included 11% Fareeduddin [42] 78 Retrospective DC Not included 9% Bhide [39] 507 Retrospective MC and DC Included 12.2-19.3% Bora [32] 77 Retrospective MC and DC Included 16.9% Banks [41] 108 Retrospective DC Not included 5% Tai [40] 178 Retrospective MC and DC Not included 11.1% Salomon [37] 182 Prospective MC and DC Included 14.3%…”