The association of crown-rump length discrepancy with birthweight discordance in spontaneous versus assisted conception dichorionic twins

Clinical implications of crown-rump length discordance at 11 to 14 weeks in dichorionic twins

BACKGROUND

Crown-rump length discordance, defined as ≥10% discordance, has been investigated as an early sonographic marker of subsequent growth abnormalities and is associated with an increased risk of fetal loss in twin pregnancies. Previous studies have not investigated the prevalence of fetal aneuploidy or structural anomalies in twins with discordance or the independent association of crown-rump length discordance with adverse perinatal outcomes. Moreover, data are limited on cell-free DNA screening for aneuploidy in dichorionic twins with discordance.

OBJECTIVE

This study aimed to evaluate whether crown-rump length discordance in dichorionic twins between 11 and 14 weeks of gestation is associated with a higher risk of aneuploidy, structural anomalies, or adverse perinatal outcomes and to assess the performance of cell-free DNA screening in dichorionic twin pregnancies with crown-rump length discordance.

STUDY DESIGN

This was a secondary analysis of a multicenter retrospective cohort study that evaluated the performance of cell-free DNA screening for the common trisomies in twin pregnancies from December 2011 to February 2020. For this secondary analysis, we included live dichorionic pregnancies with crown-rump length measurements between 11 and 14 weeks of gestation. First, we compared twin pregnancies with discordant crown-rump lengths with twin pregnancies with concordant crown-rump lengths and analyzed the prevalence of aneuploidy and fetal structural anomalies in either twin. Second, we compared the prevalence of a composite adverse perinatal outcome, which included preterm birth at <34 weeks of gestation, hypertensive disorders of pregnancy, stillbirth or miscarriage, small-for-gestational-age birthweight, and birthweight discordance. Moreover, we assessed the performance of cell-free DNA screening in pregnancies with and without crown-rump length discordance. Outcomes were compared with multivariable regression to adjust for confounders.

RESULTS

Of 987 dichorionic twins, 142 (14%) had crown-rump length discordance. The prevalence of aneuploidy was higher in twins with crown-rump length discordance than in twins with concordance (9.9% vs 3.9%, respectively; adjusted relative risk, 2.7; 95% confidence interval, 1.4-4.9). Similarly, structural anomalies (adjusted relative risk, 2.5; 95% confidence interval, 1.4-4.4]) and composite adverse perinatal outcomes (adjusted relative risk, 1.2; 95% confidence interval, 1.04-1.3) were significantly higher in twins with discordance. A stratified analysis demonstrated that even without other ultrasound markers, there were increased risks of aneuploidy (adjusted relative risk, 3.5; 95% confidence interval, 1.5-8.4) and structural anomalies (adjusted relative risk, 2.7; 95% confidence interval, 1.5-4.8) in twins with CRL discordance. Cell-free DNA screening had high negative predictive values for trisomy 21, trisomy 18, and trisomy 13, regardless of crown-rump length discordance, with 1 false-negative for trisomy 21 in a twin pregnancy with discordance.

CONCLUSION

Crown-rump length discordance in dichorionic twins is associated with an increased risk of aneuploidy, structural anomalies, and adverse perinatal outcomes, even without other sonographic abnormalities. Cell-free DNA screening demonstrated high sensitivity and negative predictive values irrespective of crown-rump length discordance; however, 1 false-negative result illustrated that there is a role for diagnostic testing. These data may prove useful in identifying twin pregnancies that may benefit from increased screening and surveillance and are not ascertained by other early sonographic markers.

[Impact of assisted reproductive technology on birth weight discordance in twins]

OBJECTIVES

To explore the association between assisted reproductive technology (ART) and birth weight discordance in twins (BWDT).

METHODS

A retrospective analysis was conducted on twin infants born between January 2011 and December 2020 at the Third Affiliated Hospital of Guangzhou Medical University, with complete basic birth data. The impact of ART on the occurrence of BWDT was identified by the multivariate logistic regression analysis.

RESULTS

A total of 3 974 pairs of twins were included, with 1 431 conceived naturally and 2 543 through ART. Neonates in the ART group had higher birth weights than those in the naturally conceived group (P<0.001). The incidence of BWDT was lower in the ART group compared to the naturally conceived group (16.17% vs 21.09%, P<0.001). The multivariate logistic regression analysis, adjusting for confounding factors such as maternal age, parity, pre-pregnancy body mass index, gestational diabetes, hypothyroidism, gestational age, and chorionic properties, showed no significant difference in the risk of BWDT between the ART and naturally conceived groups (P>0.05).

CONCLUSIONS

ART is not associated with the risk of BWDT.

Validation of Ultrasound Dating Protocols Using Data From Twins Conceived Through In Vitro Fertilization in Nova Scotia: A Retrospective Cohort Study

OBJECTIVES

Clinical practice guidelines recommend determining gestational age (GA) for twin pregnancies using the fetal crown rump length (CRL) of the larger fetus. This study investigated whether the CRL of the larger or smaller fetus at 11-14 weeks best predicted in vitro fertilization (IVF) assigned GA.

METHODS

A retrospective cohort study of twin pregnancies conceived by IVF ± intracytoplasmic sperm injection, 2004-2022, generated GA estimations for each co-twin CRL at the 11-14 week ultrasound, to determine which fetus (smaller or larger) more consistently predicted IVF-assigned GA. Monoamniotic twins and twins with known structural or vascular abnormalities were excluded. Paired t tests evaluated the ability of CRL to predict GA, and logistic regression evaluated the predictive ability of each of the co-twin groups with increasing size differences. Statistical significance was set at P < 0.05.

RESULTS

Viewpoint 6 identified 359 eligible twin pairs. CRL was closest with the smaller fetus (0.38 days); CRL for both the smaller (95% CI 0.16-0.61) and the larger (2.25 days, 95% CI 2.04-2.46) fetus showed deviation from IVF-assigned GA. As the absolute difference between the small and large fetus increased, the ultrasound-estimated GA of the smaller fetus was still consistently closer to IVF-assigned GA.

CONCLUSIONS

In this selected population of twins with known GA, the CRL of the smaller fetus more accurately predicted IVF-assigned GA even with increasing differences in fetal size. These findings provide important information for appropriately dating pregnancies to facilitate adherence to national guidelines to monitor for pregnancy complications, and plan frequency and type of fetal surveillance, as well as timing of delivery.

Pregnancy outcomes and risk factors for preeclampsia in dichorionic twin pregnancies after in vitro fertilization: a five-year retrospective study

Background

Both in vitro fertilization (IVF) and preeclampsia (PE) were associated with placental dysfunction. Although IVF can increase the incidence of PE, the pregnancy outcomes and risk factors for preeclampsia in dichorionic twin pregnancies conceived via IVF remain unclear. This study aimed to investigate the pregnancy outcomes and the risk factors for preeclampsia in dichorionic twin pregnancies conceived through IVF compared to those conceived after natural conception (NC).

Methods

This retrospective observational study enrolled 181 dichorionic twin pregnancy women with preeclampsia from 2016 to 2020. According to the mode of conception, they were allocated into IVF (n = 117) and NC groups (n = 64). The clinical characteristics of preeclampsia and pregnancy outcomes between the two groups were compared by using Student’s t test, chi-square test, and Fisher’s exact test, and logistic regression models were used to obtain adjusted odds ratios (aOR) with 95% confidence intervals (CI) for risk factors of early-onset preeclampsia.

Results

The incidence of early-onset PE and growth discordance in dichorionic twin pregnancies with PE is significantly higher in IVF-PE group than in NC group (78.60% vs 43.80%, P < 0.001, 11.10% vs 25.00%, P = 0.015). We found that IVF (aOR = 4.635, 95% CI: 2.130–10.084, P < 0.001) and growth discordance (aOR = 3.288; 95% CI: 1.090–9.749, P < 0.05) increased the incidence of early-onset PE.

Conclusions

In preeclamptic dichorionic twin pregnancies, IVF and growth discordance were associated with the increased incidence of early-onset PE. The underlying mechanism for the relationship between IVF and early-onset PE or growth discordance may be placental dysfunction.

Twin Pregnancies, Crown-rump Length and Birthweight Discordancy: The Influence of Chorionicity

OBJECTIVE

 The purpose of the present study was to analyze the influence of chorionicity in the biometric parameters crown-rump length (CRL), birthweight (BW), crown-rump length discordancy (CRLD) and birthweight discordancy (BWD), determine the correlation between these latter two in cases of intertwin discordancy, and to analyze the influence of chronicity in the presence of these discordancies with clinical relevance (> 10% and > 15%, respectively).

METHODS

 The present study was a retrospective study based on the twin pregnancy database of the Centro Hospitalar S. João (2010-2015), including 486 fetuses among 66 monochorionic (MC) and 177 dichorionic gestations (DC). The inclusion criteria were multiple pregnancies with 2 fetuses and healthy twin gestations. The exclusion criteria were trichorionic gestations and pregnancies with inconclusive chorionicity, multiple pregnancy with ≥ 3 fetuses and pathological twin gestations.

RESULTS

 No statistically significant difference was found in BW (p = 0.09) and in its discordancy (p = 0.06) nor in CRL (p = 0.48) and its discordancy (p = 0.74) between MCs and DCs. Crown-rump length discordancy and birthweight discordancy were correlated by the regression line "BWD = 0.8864 x CRLD + 0.0743," with r²  = 0.1599. Crown-rump length discordancy > 10% was found in 7.58% of monochorionic and in 13.56% of dichorionic twins. Birthweight discordancy > 15% was detected in 16.67% of monochorionic and in 31.64% of dichorionic twins.

CONCLUSION

 No statistically significant influence of chorionicity was identified in both birthweight and birthweight discordancy, as in crown-rump length and crown-rump length discordancy. Birthweight discordancy was correlated to crown-rump length discordancy in 20% of cases.

Pregnancy and perinatal outcomes of first-trimester crown-rump length discordant IVF dichorionic twin pregnancies - a retrospective cohort study

RESEARCH QUESTION

This study aimed to evaluate the association between discordance in crown-rump length (CRL) and adverse pregnancy and perinatal outcomes in dichorionic twin pregnancies.

DESIGN

This was a retrospective cohort study of dichorionic twin pregnancies after IVF that showed two live fetuses at the first ultrasound scan between 6 ⁺⁵ and 8 weeks gestational age from 1 January 2015 to 31 December 2016. Study groups were defined by the presence or absence of 20% or more discordance in CRL. The primary outcomes were early fetal loss of one or both fetuses before 12 weeks and birthweight discordance. Secondary outcomes included fetal anomalies, fetal loss between 12 and 28 weeks, stillbirth, small for gestational age (SGA) at birth, low birthweight (LBW), very low birthweight (VLBW), admission to the neonatal intensive care unit (NICU) and preterm delivery (PTD).

RESULTS

CRL-discordant twin pregnancies were more likely to end in the loss of one fetus before 12 weeks' gestation (odds ratio [OR] 15.877, 95% confidence interval [CI] 10.495-24.019). Discordant twin pregnancies with twin deliveries had a significantly higher risk of birthweight discordance (OR 1.943, 95% CI 1.032-3.989). There was no significant difference in perinatal outcomes including fetal anomalies, PTD, LBW, VLBW, SGA, neonatal death and admission to NICU between singleton or twin deliveries.

CONCLUSIONS

Discordant twin pregnancies were at increased risk of one fetal loss prior to 12 weeks' gestation. Except for birthweight discordance, there was no significant difference between CRL discordance and other adverse perinatal outcomes.

The association of crown-rump length discrepancy with birthweight discordance in spontaneous versus IVF monochorionic twins: a multicenter study

OBJECTIVE

The objective of this study was to compare the associations of crown-rump length (CRL) discrepancy with birthweight discordance in spontaneous versus in vitro fertilization (IVF) monochorionic (MC) twin pregnancies.

METHOD

This is a multicenter retrospective study on women with twin pregnancies assessed for nuchal translucency between January 1997 and July 2013. The study group was subdivided into MC twins conceived spontaneously and after IVF. Pregnancies with later fetal death or twin transfusion syndrome were excluded. A large-weight discordance was defined as a difference of birthweights of >15%.

RESULTS

The study group included 171 pregnancies; of them, 142 (83%) were spontaneous and 29 (17%) were IVF conceived. In the entire cohort, we found a significant correlation between birthweight discordance and CRL discrepancy (r = 0.173, P < 0.05). While a significant correlation was found between CRL discrepancy and birthweight discordance in spontaneous-conceived pregnancies (n = 142, r = 0.24, P = 0.005), such correlation was not present in IVF pregnancies (n = 29, r = -0.7, P = 0.724). A logistic regression analysis found significant odds of larger-weight discordance for each increase of 1% in CRL discrepancy among spontaneously conceived pregnancies (odds ratio = 1.1, confidence interval = 1.03-1.2, P = 0.005). A receiver operating characteristic (ROC) for large-weight discordance in the spontaneously conceived pregnancies demonstrated an area under the ROC curve of 0.613 (P = 0.039).

CONCLUSION

The significant correlation between CRL discrepancy and birthweight discordance in spontaneous versus IVF MC twin pregnancies might suggest differential monozygotic twinning process.