TABLE 1.
Maternal characteristics for the total population and by category of total folate concentration at <16 wk gestation
| Maternal serum total folate |
Outcome |
|||||
| Total population | Bottom tertile | Middle tertile | Upper tertile | Term birth | Preterm birth | |
| Maternal race [n (%)] | ||||||
| Non-Hispanic white | 138 (44) | 28 (27) | 43 (41) | 67 (64)1 | 125 (46) | 13 (33) |
| Non-Hispanic black | 175 (56) | 76 (73) | 62 (59) | 37 (36) | 148 (54) | 27 (67) |
| Maternal age [n (%)] | ||||||
| <20 y | 39 (12) | 10 (10) | 13 (12) | 16 (15) | 32 (12) | 7 (18) |
| 20–29 y | 227 (73) | 80 (77) | 74 (70) | 73 (70) | 203 (74) | 24 (60) |
| ≥30 y | 47 (15) | 14 (13) | 18 (17) | 15 (15) | 38 (14) | 9 (22) |
| Parity [n (%)]2 | ||||||
| 0 | 45 (14) | 10 (10) | 11 (10) | 24 (23)1 | 40 (15) | 5 (13) |
| 1 | 139 (45) | 38 (38) | 53 (51) | 48 (46) | 123 (45) | 16 (40) |
| ≥2 | 126 (41) | 53 (52) | 41 (39) | 32 (31) | 107 (40) | 19 (48) |
| Smoking status 3 mo before pregnancy [n (%)] | ||||||
| Nonsmoker | 138 (44) | 37 (36) | 44 (42) | 57 (55)3 | 117 (43) | 21 (53) |
| Smoker | 175 (56) | 67 (64) | 61 (58) | 47 (45) | 156 (57) | 19 (47) |
| Maternal education [n (%)] | ||||||
| Less than high school | 71 (23) | 28 (27) | 28 (27) | 15 (14)1 | 65 (24) | 6 (15) |
| High school or equivalent | 211 (67) | 71 (68) | 70 (67) | 70 (67) | 181 (66) | 30 (75) |
| Greater than high school | 31 (10) | 5 (5) | 7 (6) | 19 (18) | 27 (10) | 4 (10) |
| Marital status [n (%)] | ||||||
| Unmarried | 265 (85) | 92 (88) | 93 (88) | 80 (77)3 | 231 (85) | 34 (85) |
| Married | 48 (15) | 12 (12) | 12 (12) | 24 (23) | 42 (15) | 6 (15) |
| Employment status [n (%)] | ||||||
| Unemployed | 156 (50) | 54 (52) | 55 (52) | 47 (45) | 135 (49) | 135 (49) |
| Employed part time | 71 (23) | 24 (23) | 22 (21) | 25 (24) | 65 (24) | 65 (24) |
| Employed full time | 86 (27) | 26 (25) | 28 (27) | 32 (31) | 73 (27) | 73 (27) |
| Family's yearly income [n (%)]4 | ||||||
| <$10,000 | 129 (42) | 49 (48) | 45 (44) | 35 (34) | 114 (42) | 15 (38) |
| $10,000 to <$25,000 | 112 (36) | 38 (37) | 38 (37) | 36 (35) | 96 (36) | 16 (41) |
| ≥$25,000 | 66 (22) | 15 (14) | 20 (19) | 31 (31) | 58 (22) | 8 (21) |
| Prepregnancy BMI [n (%)] | ||||||
| <25.0 kg/m2 | 121 (38) | 42 (40) | 36 (34) | 43 (41) | 104 (38) | 17 (42) |
| 25.0–29.9 kg/m2 | 83 (27) | 20 (20) | 31 (30) | 32 (31) | 72 (26) | 11 (28) |
| ≥30.0 kg/m2 | 109 (35) | 42 (40) | 38 (36) | 29 (28) | 97 (36) | 12 (30) |
1
P < 0.01 (Pearson's chi-square test).
2
n = 3 with missing data on parity.
3
P < 0.05 (Pearson's chi-square test).
4
n = 6 with missing data on income.