Table 1.
Demographic and sample-related characteristics among 6,646 ECHO mother–child dyads.
| Characteristics | (%)a |
|---|---|
| Maternal race/ethnicity | |
| Non-Hispanic white | 3,470 (52.5) |
| Non-Hispanic black | 1,288 (19.5) |
| Hispanic | 1,251 (18.9) |
| Other races/ethnicitiesb | 597 (9.0) |
| Missing | 40 |
| Maternal education | |
| Less than high school | 535 (8.6) |
| High school degree/GED or equivalent | 1,337 (21.4) |
| Some college, no/associate degree, trade school | 1,115 (17.9) |
| Bachelor’s degree | 1,727 (27.7) |
| Masters, professional, or doctorate degree | 1,522 (24.4) |
| Missing | 410 |
| Maternal marital status | |
| Married or living with a partner | 4,768 (76.2) |
| Widowed, separated, divorced | 280 (4.5) |
| Single, never married, partnered, not living together | 1,213 (19.4) |
| Missing | 385 |
| Maternal age at delivery (y) | |
| 209 (3.1) | |
| 20–24 | 975 (14.7) |
| 25–29 | 1,653 (24.9) |
| 30–34 | 2,218 (33.4) |
| 35–39 | 1,290 (19.4) |
| 301 (4.5) | |
| Parity | |
| 0 | 2,566 (42.8) |
| 1 | 1,994 (33.3) |
| 1,436 (23.9) | |
| Missing | 650 |
| Prepregnancy BMI () | |
| Underweight () | 177 (2.8) |
| Normal weight (18.5–24.9) | 2,866 (46) |
| Overweight (25–29.9) | 1,607 (25.8) |
| Obese () | 1,586 (25.4) |
| Missing | 410 |
| Tobacco use during pregnancy | |
| No | 5,123 (92.8) |
| Yes | 396 (7.2) |
| Missing | 1,127 |
| Child’s sex | |
| Female | 3,250 (48.9) |
| Male | 3,396 (51.1) |
| Trimester at sample collection | |
| 1 (0–13 wk) | 29 (0.4) |
| 2 (14–26 wk) | 2,928 (44.1) |
| 3 (27 wk to the end of pregnancy) | 3,689 (55.5) |
| Sample collection season | |
| Winter (December–February) | 1,481 (22.3) |
| Spring (March–May) | 1,881 (28.3) |
| Summer (June–August) | 1,736 (26.1) |
| Autumn (September–November) | 1,548 (23.3) |
| Sample collection year | |
| 2007 | 189 (2.8) |
| 2008 | 330 (5.0) |
| 2009 | 456 (6.9) |
| 2010 | 554 (8.3) |
| 2011 | 798 (12.0) |
| 2012 | 824 (12.4) |
| 2013 | 516 (7.8) |
| 2014 | 593 (8.9) |
| 2015 | 400 (6.0) |
| 2016 | 508 (7.6) |
| 2017 | 488 (7.3) |
| 2018 | 720 (10.8) |
| 2019 | 263 (4.0) |
| 2020 | 7 (0.1) |
Note: BMI, body mass index; ECHO, Environmental influences on Child Health Outcomes; GED, general educational development.
a
Percentage was calculated without missing observations.
b
Other races/ethnicities include Asian, native Hawaiian or other Pacific Islanders, American Indian or Alaska native, and multiple race.