Table 1.
Study sample characteristics according to weighting in the NICHD Fetal Growth Studies—Singleton Cohort.
| Unweighted Overall (n = 2802) | Weighted Biomarker Sample (n = 321) 1,2,3 | |
|---|---|---|
| Age, years, median (interquartile range) | 28.0 (24.0, 32.0) | 27.6 (23.2, 31.9) |
| Race/ethnicity, % | ||
| Non-Hispanic White | 26.8 | 30.9 (23.3, 38.6) |
| Non-Hispanic Black | 27.9 | 23.3 (15.6, 31.0) |
| Hispanic | 28.7 | 27.2 (21.2, 33.2) |
| Asian/Pacific Islander | 16.7 | 18.5 (13.4, 23.7) |
| Education, % | ||
| High school or less | 29.9 | 25.1 (17.8, 32.4) |
| Some college/associate degree | 30.3 | 35.2 (27.7, 42.7) |
| College or higher | 39.7 | 39.8 (32.3, 47.3) |
| Nulliparous | 47.1 | 51.1 (43.3, 58.9) |
| Pre-pregnancy body mass index, kg/m2, % | ||
| 19.0–24.9 | 55.9 | 51.7 (43.9, 59.6) |
| 25.0–29.9 | 27.4 | 33.1 (25.3, 40.8) |
| 30.0–34.9 | 10.7 | 7.2 (3.5, 10.9) |
| 35.0–44.9 | 6.0 | 8.0 (4.2, 11.8) |
| Gestational weight gain, kg, median (interquartile range) | ||
| 10–14 weeks | 1.9 (0.2, 3.8) | 1.9 (0.4, 3.2) |
| 15–26 weeks | 4.6 (2.3, 7.3) | 4.5 (1.8, 6.8) |
| 23–31 weeks | 8.6 (5.9, 11.9) | 8.7 (5.9, 11.4) |
| 33–39 weeks | 13.5 (10.0, 16.9) | 13.6 (10.9, 17.2) |
| Total | 12.2 (8.6, 16.0) | 12.3 (8.5, 15.6) |
| Gestational diabetes, % | 3.8 | 3.9 (2.9, 4.8) |
| Preeclampsia, % | 3.5 | 2.2 (0, 4.5) |
| Preterm delivery, <37 gestational weeks, % | 5.5 | 9.1 (3.6, 14.5) |
| Gestational age at delivery, weeks, median (interquartile range) | 39.4 (38.7, 40.3) | 39.3 (38.6, 40.2) |
| Neonatal anthropometric measurements | ||
| Birthweight z-score, median (interquartile range) | −0.1 (−0.7, 0.5) | −0.1 (−0.7, 0.5) |
| Neonatal length, cm, median (interquartile range) | 50.0 (48.5, 51.8) | 50.5 (48.4, 51.8) |
| Neonatal fat mass, g, median (interquartile range) | 401.6 (300.3, 515.3) | 417.5 (329.0, 530.3) |
1 Biomarker sample selected for a case–control study of gestational diabetes nested within the NICHD Fetal Growth Studies—Singleton Cohort. The sample included 107 GDM cases and 214 non-GDM controls matched 2:1 on age, race/ethnicity, and gestational week at blood collection. 2 Descriptive statistics for variables after applying the sampling probability weight as specified in the methods. Values are presented as weighted median (interquartile range) for continuous variables and weighted percentage and 95% confidence intervals. 3 Values are presented as weighted median (interquartile range) for continuous variables and weighted percentage and 95% CI for categorical variables.