# Goal-concordant outcomes in twin pregnancies: impact of chorionicity, fetal weight discordance, and fetal surgery in a 12-year prospective cohort study

## TL;DR

The study evaluates how factors like chorionicity and fetal weight affect outcomes in twin pregnancies, using a new framework called goal-concordant outcomes.

## Contribution

Introduces a novel goal-concordant outcome framework to assess survival, delivery timing, and neonatal growth in twin pregnancies.

## Key findings

- Goal-concordant survival was significantly lower in monochorionic pregnancies with intrauterine surgery compared to dichorionic and monochorionic without intervention.
- Fetal weight discordance ≥25% was an independent risk factor for failure to achieve goal-concordant outcomes across all chorionicity groups.
- Monochorionic pregnancies with intrauterine surgery had reduced goal-concordant delivery timing and neonatal birthweight.

## Abstract

The objective of the study was to introduce a goal-concordant outcome framework and evaluate the independent effects of chorionicity, fetal weight discordance ≥25%, and intrauterine fetal surgery on survival, timing of delivery, and neonatal growth in twin pregnancies.

This prospective cohort study included 1,860 twin pregnancies delivered ≥24 weeks at a national referral center between 2012 and 2023: 1,097 pregnancies were dichorionic (DC), 559 were monochorionic without intervention (MC), and 204 were monochorionic with intrauterine surgery (MCS; 167 fetoscopic laser procedures and 37 selective reductions). The primary outcome was goal-concordant survival (GCS), defined as dual survival in DC and MC pregnancies, dual survival after laser therapy, or intended singleton survival after selective reduction. The secondary outcomes included goal-concordant week (GCW), defined as delivery within guideline-based gestational age windows, and goal-concordant weight (GCWt), defined as birthweight ≥1,500 g in all surviving neonates. Independent predictors of failure to achieve each outcome were assessed using a multivariable logistic regression analysis.

GCS was achieved in 99.0% of the DC, 98.4% of the MC, and 79.9% of the MCS pregnancies, including 78.4% after laser therapy and 86.5% after selective reduction. In a multivariable analysis, MCS was the strongest independent predictor of failure to achieve GCS (OR: 21.2, 95% CI: 10.5–42.6, p < 0.001), while fetal weight discordance ≥25% remained an additional independent risk factor (OR: 2.0, 95% CI: 1.1–3.6, p = 0.018). GCW was achieved in 52.1% of the DC, 54.2% of the MC, and 37.9% of the MCS pregnancies. Failure to achieve GCW was independently associated with fetal weight discordance ≥25% in DC and MC twins (OR: 2.9–3.1, p ≤ 0.002) and with MCS even in the absence of significant discordance (OR: 1.66, p = 0.006). GCWt was achieved in 82.9% of the DC, 69.4% of the MC, and 52.3% of the MCS pregnancies. Failure to achieve GCWt was most strongly associated with fetal weight discordance ≥25% in DC twins (OR 7.2, p < 0.001). Across chorionicity groups, pregnancies with fetal weight discordance ≥25% delivered 12–19 days earlier and had neonatal birthweights reduced by approximately 680–800 g.

Chorionicity, fetal weight discordance, and intrauterine fetal surgery independently and differentially affect survival, delivery timing, and neonatal growth. Goal-concordant outcomes provide a clinically intuitive, guideline-aligned benchmark for counseling and outcome comparison in twin pregnancies.