Maternal Recreational Exercise during Pregnancy in relation to Children’s BMI at 7 Years of Age

Table 1

Characteristics of mothers according to recreational exercise in early pregnancy^a, Danish National Birth Cohort, 1996–2002.

	All mothers (𝑛=40,280)		Non-exercising mothers (𝑛=24,492)		Exercising mothers (𝑛=15,788)
	Mean	SD	Mean	SD	Mean	SD
Maternal age (years)	30.6	4.2	30.8	4.2	30.4	4.1***
Pre-pregnancy body mass index (kg/m^2)	23.3	3.9	23.4	4.0	23.2	3.8***
Gestational weight gain (kg)	15.3	5.3	15.4	5.5	15.1	5.0***
Children's birth weight (g)	3,649	490	3,655	493	3,640	486**
Children's gestational age (days)	281.6	8.8	281.5	8.8	281.7	8.8*
Children's age at follow-up	7.1	0.3	7.1	0.3	7.1	0.3
Body mass index at 7 years (kg/m^2)	15.7	1.7	15.7	1.7	15.6	1.6***
	No.	%	No.	%	No.	%
Parity
Primiparous	19,436	48%	10,186	42%	9,206	58%
Multiparous	20,889	52%	14,288	58%	6,571	42%
𝑃-value for trend						0.01
Socio-economic status
High	22,593	56%	12,761	52%	9,797	62%
Middle	14,565	36%	9,478	39%	5,053	32%
Low	3,077	8%	2,169	9%	905	6%
𝑃-value for trend						0.01
Smoking
Non-smokers	30,892	77%	18,074	74%	12,756	81%
0–9 cigarettes/day	7,402	18%	4,858	20%	2,532	16%
≥10 cigarettes/day	2,061	5%	1,560	6%	497	3%
𝑃-value for trend						0.01
Breastfeeding
None or <14 weeks	9,058	28%	5,869	29%	3,173	25%
14–21 weeks	14,368	44%	8,586	43%	5,762	45%
≥21 weeks	9,436	28%	5,627	28%	3,786	30%
𝑃-value for trend						0.01

Data are presented as mean values ± standard deviation or number of individuals (%).
𝑃value using student's t-test or 𝝌^𝟐-test, ^∗𝑃-value < 0.05, **< 0.005, ***< 0.001 (𝑃value are 2-sided).
Abbreviations: SD, standard deviation.
^aMissing data on pre-pregnancy BMI (𝑛=624), gestational weight gain (𝑛=8,050), birth weight (𝑛=223), parity (𝑛=30), socio-economic status (𝑛=120), and breastfeeding (𝑛=7,493).