Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, TX, USA.
Department of Obstetrics & Gynaecology, Royal College of Surgeons in Ireland, Rotunda Hospital, Dublin, Ireland.
Ultrasound Obstet Gynecol. 2023 Dec;62(6):829-835. doi: 10.1002/uog.26320.
To characterize fetal growth in dichorionic twins using individualized growth assessment (IGA), a method based on individual growth potential estimates.
This secondary analysis included 286 fetuses/neonates from 143 dichorionic twin pregnancies that were part of the ESPRiT (Evaluation of Sonographic Predictors of Restricted Growth in Twins) study. The sample was subcategorized according to birth weight into appropriate-for-gestational-age (AGA) (n = 243) and small-for-gestational-age (SGA) (n = 43) cohorts. Serial biometric scans evaluating biparietal diameter, head circumference (HC), abdominal circumference, femur diaphysis length and estimated weight at 2-week intervals were used to evaluate fetal growth, while measurements of birth weight, crown-heel length and HC determined neonatal growth outcome. Six abnormalities (hypoxic ischemic encephalopathy, periventricular leukomalacia, necrotizing enterocolitis, respiratory distress, sepsis and death) constituted the evaluated adverse neonatal outcomes (ANO). IGA was used to: evaluate differences in second-trimester growth velocities between singletons (from a published dataset) and dichorionic twins (138 AGA twins with normal third-trimester growth); describe the degree to which actual third-trimester growth in twins followed expected growth (111 AGA twins, normal fetal growth and neonatal growth outcomes); determine if the fetal growth pathology score 1 (-FGPS1) could detect, quantify and classify twin growth pathology (224 AGA, 42 SGA); and assess the relationship between -FGPS1 and ANO (24 SGA twins with progressive growth restriction confirmed by abnormal neonatal growth outcome).
The differences in second-trimester growth velocity between singletons and twins (means and variances) were small and not statistically significant. Percent deviations from the expected third-trimester size trajectories were within the 95% reference ranges derived from singletons at 95.7% (1677/1752) of timepoints studied. Abnormal growth was detected in 37.9% of AGA twins and 85.7% of SGA twins. Growth restriction was more heterogeneous in AGA twins, while in SGA twins progressive growth restriction was the principal type (66.7%). -FGPS1 patterns previously defined in singletons classified 97.5% of pathological twin cases. In our most severe form of growth restriction (progressive), there were only three (12.5%) ANOs related to growth abnormalities, all in cases with -FGPS1 values more negative than -2.0%. Using these criteria, the frequency of ANO was 33%.
With respect to growth, dichorionic twins can be considered as two singletons in the same uterus. Normally growing dichorionic twins have the same growth potential as singletons with normal growth outcome. These twins also follow expected third-trimester growth trajectories with the same precision as do singletons. Third-trimester growth pathology can be detected, quantified and classified using -FGPS1 as in singletons. Limited evidence of a relationship between fetal growth abnormalities and adverse neonatal outcome was found. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.
使用基于个体生长潜力估计的个体化生长评估（IGA）方法，描述双绒毛膜双胞胎的胎儿生长情况。
本二次分析纳入了来自 ESPRiT（双胞胎生长受限的超声预测评估）研究的 143 例双绒毛膜双胞胎妊娠中的 286 例胎儿/新生儿。根据出生体重将样本分为适于胎龄（AGA）（n=243）和小于胎龄（SGA）（n=43）队列。每隔 2 周进行一次评估双顶径、头围（HC）、腹围、股骨骨干长和估计体重的系列超声检查，以评估胎儿生长情况，而出生体重、头臀长和 HC 的测量值则确定新生儿生长结局。6 种异常（缺氧缺血性脑病、脑室周围白质软化、坏死性小肠结肠炎、呼吸窘迫、败血症和死亡）构成了评估的不良新生儿结局（ANO）。IGA 用于：评估单胎（来自已发表数据集）和双绒毛膜双胞胎（138 例 AGA 双胞胎，第三孕期生长正常）在第二孕期生长速度方面的差异；描述双胞胎在第三孕期的实际生长与预期生长的符合程度（111 例 AGA 双胞胎，正常胎儿和新生儿生长结局）；确定胎儿生长病理评分 1（-FGPS1）是否可以检测、量化和分类双胞胎的生长病理（224 例 AGA，42 例 SGA）；评估 -FGPS1 与 ANO（24 例 SGA 双胞胎，通过异常新生儿生长结局证实存在进行性生长受限）之间的关系。
单胎和双胞胎的第二孕期生长速度差异（均值和方差）较小，且无统计学意义。偏离第三孕期预期生长轨迹的百分比在 95%的参考范围内，其中 95.7%（1677/1752）的时间点来自单胎。37.9%的 AGA 双胞胎和 85.7%的 SGA 双胞胎存在异常生长。AGA 双胞胎的生长受限更为混杂，而 SGA 双胞胎的主要类型为进行性生长受限（66.7%）。在单胎中先前定义的 -FGPS1 模式分类了 97.5%的病理性双胞胎病例。在我们最严重的生长受限（进行性）形式中，仅有 3 例（12.5%）与生长异常有关的 ANO，均与 -FGPS1 值小于-2.0 有关。使用这些标准，ANO 的频率为 33%。
就生长而言，双绒毛膜双胞胎可以被视为同一子宫内的两个单胎。正常生长的双绒毛膜双胞胎与具有正常生长结局的单胎具有相同的生长潜力。这些双胞胎也遵循第三孕期的预期生长轨迹，与单胎一样精确。可以使用 -FGPS1 检测、量化和分类第三孕期生长病理。有限的证据表明胎儿生长异常与不良新生儿结局之间存在关联。
