Intertwin growth discordance throughout gestation and hypertensive disorders of pregnancy

Impact of inter-twin growth discordance on preeclampsia: based on ultrasonic estimated fetal weight

A retrospective cohort study with 4396 twins who registered before 13 gestational weeks and delivered between January 2013 and December 2020 at Shanghai First Maternity and Infant Hospital, China, was conducted to clarify causal associations between inter-twin estimated fetal weight discordance and preeclampsia. Ultrasound measurements of fetal biometry were collected until the confirmation of preeclampsia diagnosis or the termination of pregnancy (when preeclampsia did not occur). Inter-twin discordance was divided into binary variables using cut-offs of 10%, 15%, and 20%. The associations between inter-twin discordance and preeclampsia were analyzed using generalized estimating equations and group-based trajectory modeling methods. The incidence of preeclampsia was 13.9%, among which 21.8% of cases were diagnosed at early onset and 55.3% at a severe stage. Inter-twin discordance based on estimated fetal weight during pregnancy was positively associated with preeclampsia. The associations were robust and constant by treating the discordance as continuous and binary. Two groups, the stable trajectory group, including 92% of participants, and the changing trajectory group, including 8% of participants, were divided according to the group-based trajectory models. Compared with the stable trajectory group, the risk of developing preeclampsia in the changing trajectory group increased by 50.3% (OR = 1.502, 95%CI: 1.073, 2.105). Subgroup analysis showed positive association primarily in early-onset preeclampsia (OR: 3.859, CI: 2.293, 6.494) and severe preeclampsia (OR: 1.896, CI: 1.264, 2.844) subgroups. These findings can provide a direction to reduce the incidence of preeclampsia in twin pregnancies, considering growth discordance as a high-risk factor in clinical practice.

Longitudinal twin growth discordance patterns and adverse perinatal outcomes

BACKGROUND

Growth discordance in twin pregnancies is associated with increased perinatal morbidity and mortality, yet the patterns of discordance progression and the utility of Doppler assessments remain underinvestigated.

OBJECTIVE

The objective of this study was to conduct a longitudinal assessment of intertwin growth and Doppler discordance to identify possible distinct patterns and to investigate the predictive value of longitudinal discordance patterns for adverse perinatal outcomes in twin pregnancies.

STUDY DESIGN

This retrospective cohort study included twin pregnancies followed and delivered at a tertiary hospital in London (United Kingdom) between 2010 and 2023. We included pregnancies with at least 3 ultrasound assessments after 18 weeks and delivery beyond 34 weeks' gestation. Monoamniotic twin pregnancies, pregnancies with twin-to-twin transfusion syndrome, genetic or structural abnormalities, or incomplete data were excluded. Data on chorionicity, biometry, Doppler indices, maternal characteristics and obstetrics, and neonatal outcomes were extracted from electronic records. Doppler assessment included velocimetry of the umbilical artery, middle cerebral artery, and cerebroplacental ratio. Intertwin growth discordance was calculated for each scan. The primary outcome was a composite of perinatal mortality and neonatal morbidity. Statistical analysis involved multilevel mixed effects regression models and unsupervised machine learning algorithms, specifically k-means clustering, to identify distinct patterns of intertwin discordance and their predictive value. Predictive models were compared using the area under the receiver operating characteristic curve, calibration intercept, and slope, validated with repeated cross-validation. Analyses were performed using R, with significance set at P<.05.

RESULTS

Data from 823 twin pregnancies (647 dichorionic, 176 monochorionic) were analyzed. Five distinct patterns of intertwin growth discordance were identified using an unsupervised learning algorithm that clustered twin pairs based on the progression and patterns of discordance over gestation: low-stable (n=204, 24.8%), mild-decreasing (n=171, 20.8%), low-increasing (n=173, 21.0%), mild-increasing (n=189, 23.0%), and high-stable (n=86, 10.4%). In the high-stable cluster, the rates of perinatal morbidity (46.5%, 40/86) and mortality (9.3%, 8/86) were significantly higher compared to the low-stable (reference) cluster (P<.001). High-stable growth pattern was also associated with a significantly higher risk of composite adverse perinatal outcomes (odds ratio: 70.19, 95% confidence interval: 24.18-299.03, P<.001; adjusted odds ratio: 76.44, 95% confidence interval: 25.39-333.02, P<.001). The model integrating discordance pattern with cerebroplacental ratio discordance at the last ultrasound before delivery demonstrated superior predictive accuracy, evidenced by the highest area under the receiver operating characteristic curve of 0.802 (95% confidence interval: 0.712-0.892, P<.001), compared to only discordance patterns (area under the receiver operating characteristic curve: 0.785, 95% confidence interval: 0.697-0.873), intertwin weight discordance at the last ultrasound prior to delivery (area under the receiver operating characteristic curve: 0.677, 95% confidence interval: 0.545-0.809), combination of single measurements of estimated fetal weight and cardiopulmonary resuscitation discordance at the last ultrasound prior to delivery (area under the receiver operating characteristic curve: 0.702, 95% confidence interval: 0.586-0.818), and single measurement of cardiopulmonary resuscitation discordance only at the last ultrasound (area under the receiver operating characteristic curve: 0.633, 95% confidence interval: 0.515-0.751).

CONCLUSION

Using an unsupervised machine learning algorithm, we identified 5 distinct trajectories of intertwin fetal growth discordance. Consistent high discordance is associated with increased rates of adverse perinatal outcomes, with a dose-response relationship. Moreover, a predictive model integrating discordance trajectory and cardiopulmonary resuscitation discordance at the last visit demonstrated superior predictive accuracy for the prediction of composite adverse perinatal outcomes, compared to either of these measurements alone or a single value of estimated fetal weight discordance at the last ultrasound prior to delivery.

The association between neonatal birthweight discordance and preeclampsia in twin pregnancy

PURPOSE

To investigate the association between neonatal birthweight (NBW) discordance and preeclampsia (PE) in twin pregnancy.

METHODS

This was a single-center retrospective cohort study. Women with two live births in the First Affiliated Hospital of Sun Yat-sen University from January 2011 to June 2020 were eligible. They were classified into four groups based on the quartiles of NBW discordance in monochorionic (MC) and dichorionic (DC) twin pregnancy. The relationship between NBW discordance and the risk of PE was assessed by logistic regression, subgroup analyses was further analyzed.

RESULTS

A total of 1566 women were eligible for the final analysis, there were 445 MC cases and 1121 DC cases. No matter in monochorionic or dichorionic pregnancy, higher NBW discordance quartiles were associated with increased risks of PE. Compared with women in the lowest NBW discordance quartile, women in the highest NBW discordance quartile had approximately 3.6 and 6.0 times risk of PE in monochorionic and dichorionic pregnancy respectively. The association between quartiles of NBW discordance and the risk of PE were higher in dichorionic pregnancy than in monochorionic pregnancy. No matter in MC or DC pregnancy, no significant interaction effects were identified for maternal age, pregnancy body mass index, mode of conception and whether complicated with gestational diabetes mellitus.

CONCLUSIONS

The increased NBW discordance quartile was related to an increased risk of PE. Assessing estimated fetal weight discordance by using ultrasound in clinical practice to predict PE remained to be further researched.

Birth weight discordance and adverse neonatal outcomes in appropriately grown premature twins

Objective

This study aimed to analyze the clinical characteristics of birth weight discordant twins (BWDT) who were premature and appropriate-for-gestational-age or large-for-gestational-age. Additionally, it assessed the impact of birth weight discordance on the prognosis of appropriately grown premature twins, and investigated the effect of maternal factors on neonatal outcomes.

Study design

This retrospective cohort study included twins who were born alive after preterm labor at the Nanjing Drum Tower Hospital from January 2018 to December 2021, along with their mothers. Twins were arranged into discordant and concordant groups according to intertwin birth weight discordance, followed by the analysis of the clinical characteristics of mothers and the prognosis of neonates.

Results

A total of 585 mothers and 1170 neonates were included, with 47 mothers and 94 neonates in the discordant group. The incidence of birth weight discordance was 8.0% (94/1,170) in appropriately grown premature twins. The incidence of complications (43.2% vs. 21.8%) and transfer to the neonatal intensive care unit (NICU) (53.2% vs. 29.2%) was higher in the discordant group than in the concordant group (p < 0.05). Furthermore, the incidence of infectious diseases (36.7% vs. 19.4%), necrotizing enterocolitis (7.6% vs. 1.6%), and oxygen therapy rate (22.8% vs. 12.8%) were statistically significantly higher in the discordant group than in the concordant group (p < 0.05).

Conclusion

Birth weight discordance remains a high-risk factor for complications and transfer to the NICU in appropriately grown premature twins. It is important to pay attention to birth weight discordance when the outcomes of twins are assessed.