Table 1.

Maternal and paternal BMI across categories of maternal, paternal, and child characteristics among all singletons and one randomly selected twin of each pair.

Characteristic	Maternal pre-pregnancy BMI, kg/m2		Paternal BMI at 4 months post-partum, kg/m2
	n	Mean ± SD	n	Mean ± SD
Total	1605	26.9 ± 7.0	1505	28.3 ± 5.5
Maternal characteristics
Age, years
<25	205	26.9 ± 7.1	175	26.3 ± 5.7
25–29	428	27.5 ± 7.7	398	28.6 ± 5.8
30–34	546	26.5 ± 6.7	498	28.5 ± 5.3
35–39	327	26.4 ± 6.3	304	28.6 ± 4.9
≥40	144	27.5 ± 6.9	130	28.4 ± 5.5
P-trend1		0.45		0.004
Race / ethnicity
Non-Hispanic white	1411	27.0 ± 7.0	1303	28.4 ± 5.5
Other	239	26.4 ± 6.9	202	27.6 ± 5.5
p2		0.28		0.05
Education
Less than high school	53	28.8 ± 10.0	35	26.6 ± 7.0
High school of GED equivalent	158	28.8 ± 8.4	138	28.2 ± 7.1
Some college	421	29.0 ± 7.9	390	29.0 ± 5.6
College	414	26.0 ± 6.2	383	28.0 ± 5.2
Advanced degree	604	25.3 ± 5.4	559	28.0 ± 4.9
P-trend		<0.0001		0.29
Private insurance
Yes	1354	26.5 ± 6.4	1260	28.4 ± 5.3
No	296	28.4 ± 8.9	245	27.7 ± 6.1
P		<0.0001		0.06
Married or living as married
Yes	1468	26.8 ± 6.9	1390	28.3 ± 5.4
No	139	28.4 ± 8.4	102	27.1 ± 6.5
P		0.01		0.02
History of affective disorder
Yes	288	28.1 ± 7.5	267	28.1 ± 5.7
No	1337	26.6 ± 6.8	1238	28.3 ± 5.4
P		0.001		0.50
Diagnosis of polycystic ovary syndrome
Yes	194	30.4 ± 8.2	183	30.4 ± 6.1
No	1427	26.4 ± 6.7	1319	28.0 ± 5.3
P		<0.0001		<0.0001
Smoking during pregnancy
Yes	162	28.1 ± 8.0	145	26.9 ± 5.8
No	1487	26.7 ± 6.8	1359	28.4 ± 5.4
P		0.02		0.002
Alcohol use during pregnancy
Yes	209	25.1 ± 5.3	199	27.7 ± 4.9
No	1440	27.1 ± 7.2	1305	28.4 ± 5.5
P		<0.0001		0.10
Paternal characteristics
Age, years
<25	113	27.0 ± 7.1	104	26.4 ± 6.2
25–29	306	27.0 ± 7.2	286	28.4 ± 5.7
30–34	507	26.6 ± 6.6	474	28.3 ± 5.2
35–39	358	26.8 ± 6.8	334	29.0 ± 5.8
≥40	277	26.7 ± 6.8	257	28.3 ± 4.9
P-trend		0.60		0.02
History of an affective disorder
Yes	127	27.5 ± 6.4	122	29.0 ± 5.8
No	1498	26.8 ± 7.0	1383	28.2 ± 5.4
P		0.32		0.11
Child characteristics
Sex
Male	876	27.0 ± 7.0	796	28.3 ± 5.6
Female	774	26.8 ± 6.9	709	28.2 ± 5.3
P		0.66		0.59

¹P-trend from a linear regression model with BMI as the continuous outcome where a variable representing ordinal categories of the predictor was introduced as a continuous covariate.

²Wald chi-squared test.