NICHD Fetal Growth Study: Twin Gestations
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 发起方
- 入组人数
- 171
- 试验地点
- 9
- 主要终点
- Fetal growth trajectories in dichorionic twin pregnancies
研究概览
简要总结
Normal growth and development of twins are important for the long-term health of the children. The purpose of this study was to empirically define the trajectory of fetal growth in dichorionic twins using longitudinal two-dimensional ultrasonography and to compare the fetal growth trajectories for dichorionic twins with those based on a growth standard developed by our group for singletons. This knowledge may lead to interventions that could minimize or prevent pregnancy and newborn health problems in the future.
详细描述
A prospective cohort of 171 women with twin gestations was recruited from eight U.S. sites from 2012 to 2013. After an initial sonogram at 11w0d-13w6d where dichorionicity was confirmed, women were randomized to one of two serial ultrasonology schedules. Ultrasound measurements at each follow-up visit included standard fetal biometrics ((BPD, HC, AC, FL); estimated fetal weight was calculated using a Hadlock formula. Growth curves and percentiles were estimated using linear mixed models with cubic splines. Percentiles were compared statistically at each gestational week between the twins and 1,731 singletons in the Fetal Growth Studies-Singletons cohort.
In addition to 2-D ultrasound measures for analyzing fetal growth, this study recorded maternal anthropometrics and a brief interview to capture changes in health status, stress and depression, and physical activity at each follow-up visit. Four blood draws at baseline and at targeted gestational ages for the eventual identification of biomarkers indicative of fetal growth were collected. After delivery, neonatal anthropometric measures were assessed for each twin, placental biospecimens were collected, and select information about the obstetrical course and newborn status were abstracted from medical charts. These exposures and outcomes provide opportunities to further compare singleton and twin gestations with respect to maternal biomarkers of fetal growth, well-being and maternal nutritional status using banked biospecimens to determine if the biomarkers ranges established for singletons are applicable to twin gestations.
Biospecimen Description:
- Maternal blood sample (serum, plasma, white blood cells, red blood cells and PAXgene RNA) at enrollment, 1st, 3rd, 5th follow-up visits, and delivery
- Cord blood and placentas for consenting women collected at delivery
- Placenta sample or buccal swab (determining zygosity by DNA probe for same sex pairs), collected at delivery
研究设计
- 研究类型
- Observational
- 观察模型
- Cohort
- 时间视角
- Prospective
入排标准
- 年龄范围
- 18 Years 至 45 Years（Adult）
- 性别
- Female
- 接受健康志愿者
- 是
入选标准
- 未提供
排除标准
- 未提供
结局指标
主要结局
Fetal growth trajectories in dichorionic twin pregnancies
时间窗: 3 years
Fetal growth trajectories in dichorionic twin pregnancies were created using two- and selected three-dimensional ultrasound measures. Measures included maternal anthropometric measurements and 2D fetal biometry (BPD, HC, AC, FL) using standardized protocols. Women were recruited during the first trimester and followed until delivery. Each woman had seven scheduled ultrasound examinations, one at enrollment and six during follow-up visits. Women were randomized to receive sonograms according to one of the following two schedules: schedule A: 16, 20, 24, 28, 32 and 35 weeks or schedule B: 18, 22, 26, 30, 34 and 36 weeks.
Comparison of the fetal growth trajectories for dichorionic twins with singletons
时间窗: 3 years
The primary analysis compared fetal growth trajectories for dichorionic twins with 1,737 singleton gestations included in the NICHD Fetal Growth Studies - Singleton standard. For modeling twin trajectories, we used linear mixed models with a cubic spline mean structure and a random effects structure that included linear, quadratic, and cubic random effects for the twin pair and an intercept term for the individual fetus within twin pair. The linear mixed models were also used to test for overall differences (i.e., global tests) between the twin and singleton trajectories (for EFW and other measurements) using likelihood ratio tests of interaction terms between spline mean structure terms and twin-singleton indicator variables.
Incidence of fetal growth restriction (with small-for-gestational age as a proxy) in dichorionic twins (by zygosity)
时间窗: 3 years
Using small-for-gestational age as a proxy for growth restriction, we evaluated the percentage of dichorionic twins who would be classified below the 10th percentile using the study-generated singleton non-Hispanic white standard.
Comparison of singleton and twin gestations for maternal biomarkers of fetal growth
时间窗: 3 years
Longitudinal data will compare singleton and twin gestations with respect to maternal biomarkers of fetal growth, well-being and maternal nutritional status using banked biospecimens to determine if the biomarkers ranges established for singletons are applicable to twin gestations.
次要结局
- Body composition(3 years)
- Genetic and environmental factors affecting fetal growth(3 years)
- Biospecimen repository(3 years)
- Conception mode and growth trajectories(3 years)
- Zygosity and growth trajectories(3 years)
- Placental pathology and growth trajectories(3 years)