Table 2.
Unadjusted percent and adjusteda risk of second pregnancy incident and recurrent small-for-gestational-age birth by second pregnancy characteristics, Consecutive Pregnancy Study, 2002–2010, n=25,241.
| Second Pregnancy Risk Factors | Incident SGAb | Recurrent SGAb | Pdifferenced | ||||
|---|---|---|---|---|---|---|---|
| % | RR (95% CI) | Pc | % | RR (95% CI) | Pc | ||
| Age, years | .01 | .35 | .01 | ||||
| 14–19 | (7.8) | 1.48 (1.09, 2.02) | (19.7) | 0.75 (0.50, 1.12) | |||
| 20–24 | (5.5) | 1.21 (1.06, 1.39) | (20.2) | 0.89 (0.74, 1.08) | |||
| 25–29 | (4.2) | 1.00 (Referent) | (20.6) | 1.00 (Referent) | |||
| 30–34 | (3.9) | 0.94 (0.78, 1.14) | (18.7) | 0.93 (0.73, 1.19) | |||
| 35–49 | (3.9) | 0.91 (0.65, 1.27) | (23.0) | 1.21 (0.87, 1.70) | |||
| Race-ethnicity | .20 | .46 | .21 | ||||
| Non-Hispanic white | (4.5) | 1.00 (Referent) | (20.0) | 1.00 (Referent) | |||
| Non-Hispanic black | (12.1) | 2.25 (1.26, 4.01) | (30.4) | 1.38 (0.75, 2.53) | |||
| Hispanic | (5.8) | 1.03 (0.83, 1.28) | (24.2) | 1.01 (0.78, 1.30) | |||
| Asian/Pacific Islander | (6.0) | 1.32 (0.92, 1.89) | (17.6) | 0.71 (0.44, 1.14) | |||
| Other | (3.2) | 0.67 (0.22, 2.01) | (23.5) | 1.08 (0.51, 2.27) | |||
| Marital status | .36 | .97 | .57 | ||||
| Married | (4.4) | 1.00 (Referent) | (19.8) | 1.00 (Referent) | |||
| Non-married | (6.8) | 1.10 (0.90, 1.35) | (22.5) | 1.00 (0.78, 1.29) | |||
| Insurance | .52 | .08 | .30 | ||||
| Private | (4.4) | 1.00 (Referent) | (18.8) | 1.00 (Referent) | |||
| Public | (5.6) | 1.05 (0.91, 1.21) | (23.4) | 1.19 (0.98, 1.44) | |||
| Smoking during pregnancy | .005 | .01 | .90 | ||||
| No | (4.5) | 1.00 (Referent) | (19.7) | 1.00 (Referent) | |||
| Yes | (9.9) | 1.64 (1.22, 2.19) | (29.9) | 1.59 (1.17, 2.17) | |||
| Alcohol during pregnancy | .57 | .94 | .65 | ||||
| No | (4.6) | 1.00 (Referent) | (20.2) | 1.00 (Referent) | |||
| Yes | (6.4) | 1.14 (0.75, 1.73) | (22.2) | 0.98 (0.60, 1.60) | |||
| Short stature | <.001 | <.001 | .20 | ||||
| No | (4.3) | 1.00 (Referent) | (17.8) | 1.00 (Referent) | |||
| Yes | (6.4) | 1.34 (1.16, 1.54) | (26.6) | 1.54 (1.31, 1.82) | |||
| Prepregnancy weight status | <.001 | .004 | .77 | ||||
| Underweight | (7.8) | 1.32 (1.07, 1.64) | (30.9) | 1.30 (1.03, 1.64) | |||
| Normal weight | (5.0) | 1.00 (Referent) | (21.2) | 1.00 (Referent) | |||
| Overweight | (4.1) | 0.91 (0.77, 1.06) | (16.7) | 0.84 (0.67, 1.05) | |||
| Obese | (3.3) | 0.64 (0.52, 0.78) | (14.6) | 0.73 (0.55, 0.97) | |||
| Gestational weight gain adequacy | <.001 | <.001 | .49 | ||||
| Inadequate | (7.4) | 1.41 (1.22, 1.64) | (28.1) | 1.33 (1.10, 1.60) | |||
| Within | (5.1) | 1.00 (Referent) | (20.6) | 1.00 (Referent) | |||
| Excessive | (3.2) | 0.63 (0.54, 0.74) | (13.3) | 0.69 (0.55, 0.87) | |||
| Diabetes | .11 | .03 | .13 | ||||
| None | (4.7) | 1.00 (Referent) | (20.4) | 1.00 (Referent) | |||
| Gestational | (4.0) | 0.82 (0.57, 1.19) | (11.3) | 0.48 (0.22, 1.01) | |||
| Prepregnancy | (3.0) | 0.64 (0.35, 1.15) | (21.4) | 1.20 (0.67, 2.16) | |||
| Hypertension | <.001 | .48 | .03 | ||||
| Normotensive | (4.5) | 1.00 (Referent) | (20.2) | 1.00 (Referent) | |||
| Gestational hypertension | (6.4) | 1.90 (1.35, 2.67) | (20.8) | 1.47 (0.94, 2.31) | |||
| Preeclampsia | (11.4) | 3.14 (2.38, 4.13) | (22.6) | 1.34 (0.83, 2.17) | |||
| Chronic hypertension | (4.3) | 1.24 (0.71, 2.17) | (19.4) | 1.25 (0.63, 2.44) | |||
| Superimposed preeclampsia | (8.9) | 2.98 (1.28, 6.94) | (25.0) | 1.64 (0.39, 6.99) | |||
| Asthma | .18 | .91 | .45 | ||||
| No | (4.6) | 1.00 (Referent) | (20.3) | 1.00 (Referent) | |||
| Yes | (5.3) | 1.16 (0.95, 1.41) | (19.7) | 1.02 (0.77, 1.33) | |||
| Thyroid disease | .68 | .99 | .82 | ||||
| No | (4.7) | 1.00 (Referent) | (20.3) | 1.00 (Referent) | |||
| Yes | (4.4) | 1.06 (0.81, 1.40) | (18.4) | 1.00 (0.67, 1.51) | |||
| Depression or other mental health condition | .16 | .09 | .03 | ||||
| No | (4.6) | 1.00 (Referent) | (20.6) | 1.00 (Referent) | |||
| Yes | (5.6) | 1.14 (0.96, 1.37) | (17.8) | 0.81 (0.62, 1.05) | |||
| Interpregnancy interval, months | .07 | .06 | .47 | ||||
| <12 | (4.6) | 0.96 (0.80, 1.14) | (18.7) | 0.91 (0.72, 1.14) | |||
| 12–<18 | (4.7) | 1.10 (0.92, 1.30) | (18.1) | 0.90 (0.71, 1.15) | |||
| 18–23 | (4.3) | 1.00 (Referent) | (20.6) | 1.00 (Referent) | |||
| >23 | (5.0) | 1.17 (0.99, 1.40) | (23.8) | 1.18 (0.94, 1.47) | |||
CI, confidence interval; RR, risk ratio; SGA, small-for-gestational-age.
a
Model adjusted for all characteristics shown in table.
b
SGA defined using the 10th percentile of a population-based reference.
c
P represents the global significance of the maternal characteristics within the respective recurrent or incident SGA group.
d
Pdifference represents the interaction between recurrent and incident SGA for the respective characteristic.