Abstract
BACKGROUND: Hypertensive disorders of pregnancy (HDP) significantly impact infant outcomes. However, evidence regarding HDP's effects on twin pregnancies remains limited and poorly characterized. This study aimed to investigate the impact of HDP on perinatal outcomes and neonatal complications in twin pregnancies. METHODS: Data were collected from 22 medical centers across 12 Chinese provinces between January 2018 and December 2020. The primary variable of interest was HDP (including gestational hypertension and preeclampsia). Perinatal outcomes and neonatal complications were systematically assessed using multivariable logistic regression, propensity score matching, and overlap weighting (OW). RESULTS: Among 6,307 twin pregnancies, 1,013 cases (16.1%) were diagnosed with HDP. HDP significantly increased the likelihood of preterm birth (2.68 [2.27-3.15] (OW)). Specifically, it elevated the rates of early and late preterm births (1.29 [1.00-1.67] (OW) and 2.31 [2.00-2.68] (OW), respectively), while reducing the risk of extremely preterm births (0.32 [0.12-0.77] (OW)). Moreover, HDP was associated with increased rates of low birth weight and small-for-gestational-age (OW-OR [95%CI] of 1.54 [1.34-1.78] and 1.18 [1.00-1.42], respectively), and heightened risk of birth weight discordance (> 15%, > 20%, and > 25%). For twin complications, HDP elevated oxygen requirement (1.29 [1.07-1.56] (OW)), 1-minute Apgar scores < 7 (1.29 [1.07-1.56] (OW)), and NICU admissions (1.58 [1.32-1.90] (OW)). Stratified and sensitivity analyses reaffirmed the robustness. CONCLUSIONS: HDP increases adverse perinatal and neonatal outcomes in twins. Therefore, careful monitoring and management are imperative for mothers diagnosed with HDP carrying twins to mitigate these adverse outcomes. TRIAL REGISTRATION: NA.