TABLE 1—
Percentage Distribution of Key Variables by ART and Autism Status: California 1997–2007
| Variable | Non-ART (n = 5 877 386), % | ART (n = 48 865), % | Pa | No Autism (n = 5 893 329), % | Autism (n = 32 922), % | Pa |
| Birth year | ≤ .001 | ≤ .001 | ||||
| 1997 | 8.9 | 4.1 | 8.9 | 7.2 | ||
| 1998 | 8.8 | 5.5 | 8.8 | 7.8 | ||
| 1999 | 8.8 | 5.9 | 8.8 | 8.1 | ||
| 2000 | 9.0 | 6.4 | 9.0 | 9.1 | ||
| 2001 | 8.9 | 8.3 | 8.9 | 9.6 | ||
| 2002 | 8.9 | 9.8 | 8.9 | 10.2 | ||
| 2003 | 9.1 | 10.9 | 9.1 | 11.0 | ||
| 2004 | 9.2 | 11.6 | 9.2 | 10.5 | ||
| 2005 | 9.3 | 11.9 | 9.3 | 10.0 | ||
| 2006 | 9.5 | 12.2 | 9.5 | 9.1 | ||
| 2007 | 9.5 | 13.3 | 9.6 | 7.4 | ||
| Infant’s gender | .335 | ≤ .001 | ||||
| Female | 48.9 | 49.1 | 49.0 | 16.8 | ||
| Male | 51.1 | 50.9 | 51.0 | 83.2 | ||
| Plurality | ≤ .001 | ≤ .001 | ||||
| Singleton | 97.5 | 47.3 | 97.1 | 94.8 | ||
| Twin | 2.4 | 46.4 | 2.8 | 4.8 | ||
| Triplet or more | 0.1 | 6.4 | 0.1 | 0.4 | ||
| Parity | ≤ .001 | ≤ .001 | ||||
| Multiparous | 61.3 | 49.6 | 61.3 | 56.6 | ||
| Primiparous | 38.7 | 50.4 | 38.7 | 43.4 | ||
| Mother’s age, y | ≤ .001 | ≤ .001 | ||||
| < 20 | 10.2 | 0.0 | 10.1 | 5.1 | ||
| 20–24 | 23.2 | 0.4 | 23.1 | 17.8 | ||
| 25–29 | 26.5 | 6.5 | 26.3 | 25.4 | ||
| 30–34 | 24.0 | 27.7 | 24.0 | 28.0 | ||
| 35–39 | 13.0 | 37.4 | 13.1 | 18.5 | ||
| ≥ 40 | 3.1 | 28.0 | 3.3 | 5.2 | ||
| Mother’s race | ≤ .001 | ≤ .001 | ||||
| Non-Hispanic White | 30.6 | 67.7 | 30.9 | 34.4 | ||
| Black | 6.3 | 2.4 | 6.2 | 7.4 | ||
| Hispanic | 49.8 | 11.1 | 49.5 | 40.8 | ||
| Asian or Pacific Islander | 11.9 | 16.2 | 11.9 | 16.0 | ||
| Native American | 0.5 | 0.2 | 0.4 | 0.4 | ||
| Other or unknown | 1.0 | 2.5 | 1.0 | 1.0 | ||
| Mother’s birthplace | ≤ .001 | ≤ .001 | ||||
| US and US territories | 54.1 | 72.1 | 54.3 | 56.3 | ||
| Outside US | 45.9 | 27.9 | 45.7 | 43.7 | ||
| Mother’s education | ≤ .001 | ≤ .001 | ||||
| < high school diploma | 30.3 | 2.2 | 30.2 | 18.8 | ||
| High school diploma | 27.8 | 9.5 | 27.6 | 26.2 | ||
| Some college | 20.0 | 18.2 | 19.9 | 24.9 | ||
| ≥ 4-y college graduate | 21.9 | 70.1 | 22.3 | 30.1 | ||
| Small for gestational age | ≤ .001 | ≤ .001 | ||||
| ≥ 10th percentile | 90.4 | 78.1 | 90.4 | 89.2 | ||
| < 10th percentile | 9.6 | 21.9 | 9.6 | 10.8 | ||
| Preterm | ≤ .001 | ≤ .001 | ||||
| ≥ 37 wk | 89.5 | 63.8 | 89.3 | 86.6 | ||
| < 37 wk | 10.5 | 36.2 | 10.7 | 13.4 | ||
| Hypertension or preeclampsia | ≤ .001 | ≤ .001 | ||||
| None recorded | 97.5 | 92.8 | 97.5 | 96.6 | ||
| Present | 2.5 | 7.2 | 2.5 | 3.4 | ||
| Maternal diabetes | ≤ .001 | ≤ .001 | ||||
| None recorded | 98.0 | 96.9 | 98.0 | 97.0 | ||
| Present | 2.0 | 3.1 | 2.0 | 3.0 | ||
| Mode of delivery | ≤ .001 | ≤ .001 | ||||
| Vaginal | 73.7 | 35.5 | 73.4 | 65.3 | ||
| Cesarean | 26.3 | 64.5 | 26.6 | 34.7 | ||
| Trimester prenatal care begun | ≤ .001 | |||||
| None | 0.6 | 0.1 | 0.6 | 0.3 | ||
| First | 84.8 | 96.7 | 84.9 | 88.8 | ||
| Second | 12.2 | 3.0 | 12.1 | 9.3 | ||
| Third | 2.4 | 0.2 | 2.4 | 1.6 | ||
| Payment source for prenatal care | ≤ .001 | ≤ .001 | ||||
| Private insurance or payment | 54.3 | 97.0 | 54.6 | 64.6 | ||
| Public source | 45.7 | 3.0 | 45.4 | 35.4 | ||
| Payment source for delivery | ≤ .001 | ≤ .001 | ||||
| Private insurance or payment | 53.9 | 97.0 | 54.2 | 64.3 | ||
| Public source | 46.1 | 3.0 | 45.8 | 35.7 | ||
| Adequacy of prenatal care | ≤ .001 | ≤ .001 | ||||
| Missing | 3.0 | 2.3 | 3.0 | 2.4 | ||
| Inadequate | 9.6 | 1.2 | 9.6 | 6.8 | ||
| Intermediate | 12.7 | 4.7 | 12.6 | 11.2 | ||
| Adequate | 41.3 | 22.2 | 41.1 | 40.3 | ||
| Adequate plus | 33.5 | 69.6 | 33.7 | 39.3 | ||
| DDS autism status | ≤ .001 | ≤ .001 | ||||
| No autism | 99.4 | 98.8 | ||||
| Autism | 0.6 | 1.2 | ||||
| Originated using ART? | ≤ .001 | |||||
| No | 99.2 | 98.2 | ||||
| Yes | 0.8 | 1.8 |
Note. ART = assisted reproductive technology; DDS = California Department of Developmental Services.
a
We derived P values from the χ2 test for association between categorical predictor variable and ART conception or autism status.