Differences in short-term neonatal outcomes between discordant twins

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.

Growth parameters of discordant preterm twins during the first year of life

OBJECTIVE

To evaluate and compare growth parameters (weight, length and head circumference) of discordant preterm twins during the first year of life.

METHODS

Retrospective data were collected on 78 pairs of >10% discordant preterm twins. Data regarding short-term neonatal outcome were recorded. Growth parameters were recorded at birth and again at 1 year of age, as collected by phone interview.

RESULTS

At 1 year of age, the gap was significantly reduced between the group of smaller twins and the group of larger twins on all the parameters studied. Discordance in weight decreased from a mean of 22% at birth (calculated from the weight of the larger twin) to 8.9%, in length from 6.5% to 2.5% and in head circumference from 5.5% to 1.3% at 1 year of age. While length and head circumference (HC) z-scores improved in both the large and the small siblings, weight z-score decreased significantly among the large twins and decreased mildly among the small twins.

CONCLUSIONS

The gaps in growth parameters between the smaller twins of preterm discordant twins and their larger siblings are significantly reduced during the first year of life. The impact of the differential growth patterns between the two siblings should be further evaluated.

Discordance in neonatal risk factors and early childhood outcomes of very low birth weight (<1.5 kg) twins

OBJECTIVE

To examine the rates of discordance in neonatal risk factors and neurodevelopmental outcomes within very low birth weight twin pairs and the factors associated with discordant outcomes.

STUDY DESIGN

Rates of neonatal risk factors and neurodevelopmental outcomes, and discordance in outcomes were examined for 88 very low birth weight twin pairs born between 1990 and 2005 and followed through 20 months' corrected age.

RESULT

Discordance rates ranged from 17 to 42% for neonatal risk factors and from 18 to 31% for neurodevelopmental outcomes. In regression analysis, affected co-twins were significantly more likely to have had an abnormal cerebral ultrasound than their unaffected co-twins in pairs discordant for cerebral palsy (odds ratio (OR): 13.00, 95% confidence interval (CI): 2.22 to 76.03)) and in pairs discordant for neurodevelopmental impairment (OR: 4.00, 95% CI: 1.13 to 14.18). Outcomes and discordance in outcomes were similar for monochorionic and dichorionic pairs.

CONCLUSION

Despite shared genetics and risk factors, twins may have discordant outcomes. Information on discordant neonatal and neurodevelopmental outcomes is important for counseling families of twins.

Discordant twins: diagnosis, evaluation and management

Approximately 16% of twin gestations have discordance of at least 20%. We identified 14 risk factors for divergent growth that can be categorized as maternal, fetal, or placental. Determination of chorionicity and serial ultrasound evaluation with a high index of suspicion for divergent growth is required for the diagnosis and stratification of risk. The highest reported likelihood ratio for detection of discordance was 5.9 during the first trimester examination and 6.0 for the second trimester. Although our ability to identify discordant twins is limited, once suspected and at viable gestational age, these pregnancies should have antepartum testing. Discordant growth alone is not an indication for preterm birth. Although there are multiple publications on the increased morbidity and mortality rates with discordant growth, there is a paucity of reports on how to manage them optimally and deliver them in a timely manner.