Do parental heights influence pregnancy length?: a population-based prospective study, HUNT 2

Table 4 Mean differences in length of pregnancy by maternal height ¹ restricted to pregnancies with spontaneous onset of delivery²

		Difference in pregnancy length (days)
		Crude estimate³	Adjusted for obstetric and socioeconomic factors⁴			Additional adjustment for maternal cardiovascular risk factors⁵
Maternal height (in quintiles)	N	Mean difference	Mean difference	95% CI	p for trend	Mean difference	95% CI	p for trend
Estimated date of delivery based on US
<163	687	0	0	Ref		0	Ref
163-165	593	0.5	0.5	−0.8,1.8		0.5	−0.8,1.8
166-168	654	1.8	1.9	0.5,3.3		1.9	0.5,3.3
169-172	703	1.8	1.9	0.5,3.2		1.8	0.4,3.1
173+	509	3.5	3.6	2.3,4.8	<0.001	3.5	2.2,4.8	<0.001
Estimated date of delivery based on LMP
<163	850	0	0	Ref		0	Ref
163-165	723	0.3	0.4	−1.0,1.7		0.4	−1.0,1.8
166-168	808	1.3	1.4	0.0,2.9		1.4	0.0,2.9
169-172	839	0.6	0.6	−0.7,2.0		0.6	−0.7,2.0
173+	611	1.8	1.8	0.4,3.3	0.02	1.9	0.4,3.4	0.02

¹Pregnancy length according to date of delivery estimated by ultrasound (US) (3146 pregnancies) and by first day of last menstrual period (LMP) (3831 pregnancies). ²Exclusion of pregnancies with induced onset of delivery (medically or by caesarean section). ³Adjusted for maternal age at baseline (HUNT 2 participation). ⁴Additionally adjusted for maternal age at birth, duration between Hunt 2 participation and delivery, maternal education, parity, maternal smoking, receiving social security benefits or not, and fetal sex. ⁵Additionally adjusted for pre-pregnancy maternal hypertension, diabetes mellitus, kidney and heart disease, BMI; systolic and diastolic blood pressure, concentration of glucose and lipids.
Pregnancies restricted to spontaneous onset of delivery².

ISSN: 1471-2393