Table 1.
Characteristics of Liveborn Infants by Mode of Conception in Florida, Massachusetts, and Michigan, 2000–2010
| Characteristica | No. (%)b | |
|---|---|---|
| ART (n = 64 861) | Non-ART (n = 4 553 215) | |
| Plurality | ||
| Singleton | 33 601 (51.8) | 4 421 154 (97.1) |
| Twins | 28 031 (43.2) | 127 013 (2.8) |
| Triplets/higher | 3229 (5.0) | 5048 (0.1) |
| Infant sex | ||
| Male | 33 213 (51.2) | 2 331 340 (51.2) |
| Female | 31 648 (48.8) | 2 221 767 (48.8) |
| Birth weight, g | ||
| <2500 | 20 843 (32.2) | 357 027 (7.8) |
| <1500 | 4172 (6.4) | 66 580 (1.5) |
| Gestational age, wk | ||
| <37 | 23 456 (36.3) | 444 005 (9.8) |
| <32 | 4742 (7.3) | 74 063 (1.6) |
| State of residence | ||
| Florida | 21 636 (33.4) | 2 333 367 (51.2) |
| Massachusetts | 29 736 (45.8) | 853 165 (18.7) |
| Michigan | 13 489 (20.8) | 1 366 683 (30.0) |
| Maternal age, y | ||
| <30 | 7480 (11.5) | 2 742 518 (60.2) |
| 30–34 | 22 587 (34.8) | 1 120 673 (24.6) |
| 35–37 | 15 228 (23.5) | 411 713 (9.0) |
| 38–40 | 10 821 (16.7) | 202 982 (4.5) |
| ≥41 | 8745 (13.5) | 75 161 (1.7) |
| Race/ethnicity | ||
| Non-Hispanic white | 52 636 (81.4) | 2 651 395 (58.4) |
| Non-Hispanic black | 2629 (4.1) | 823 410 (18.1) |
| Hispanic | 648 (1.0) | 58 761 (1.3) |
| Asian/Pacific Islander | 5598 (8.7) | 838 398 (18.5) |
| Other/mixed | 3159 (4.9) | 165 831 (3.7) |
| Maternal education, y | ||
| <12 | 883 (1.4) | 794 055 (17.6) |
| 12 | 7788 (12.1) | 1 378 011 (30.5) |
| Some college | 13 767 (21.3) | 1 121 534 (24.8) |
| College graduate | 42 051 (65.2) | 1 217 657 (27.0) |
| Parity | ||
| Nulliparous | 42 697 (66.1) | 1 906 727 (42.0) |
| Multiparous | 21 884 (33.9) | 2 628 451 (58.0) |
| Tobacco use during pregnancyc | 806 (1.2) | 463 004 (10.2) |
| Diabetesd | 4501 (7.0) | 184 442 (4.1) |
| Hypertensione | 6386 (9.8) | 232 898 (5.1) |
Abbreviation: ART, assisted reproductive technology.
a
Missing data less than 1% for all variables.
b
P < .01 for all comparisons between ART births and non-ART births except for infant sex. P values account for clustering of infants within a live birth delivery and clustering of sibling births and were adjusted using the Holm-Bonferroni method.
c
Includes women who smoked during the pregnancy but quit for 2004 to 2010 Florida data and 2010 Michigan data.
d
Includes chronic and gestational diabetes.
e
Includes chronic and pregnancy-induced hypertension.