Table 4.

Environmental pollutant concentration in amniotic fluid according to maternal parity at amniocentesis, Denmark, 1980–1996.

5cx-MEPP							7cx-MMeHP							PFOS
Parity	n	Mean (ng/mL)	Median (ng/mL)	Percent change (95% CI)a	p-Valueb	Mean (ng/mL)	Median (ng/mL)	Percent change (95% CI)a	p-Valueb	Mean (ng/mL)	Median (ng/mL)	Percent change (95% CI)a	p-Valueb
0		106		0.32		0.26						0.09		0.07						1.21		1.08
1		93		0.35		0.26		9.4 (–6.5, 28.1)		0.82		0.10		0.08		21.8 (1.2, 46.6)		0.06		1.23		1.03		–2.5 (–19.4, 17.9)		0.76
≥ 2		101		0.30		0.27		–4.3 (–18.8, 12.9)		0.64		0.08		0.06		–5.6 (–22.3, 14.5)		0.17		1.18		1.09		–2.2 (–19.8, 19.3)		0.84
aThe ratio of medians estimated by linear regression with the pollutant concentration on the ln scale and adjusted for year of amniocentesis, gestational age at amniocentesis, maternal age, and maternal smoking. Reference group is nullipara. bWilcoxon rank-sum test with nullipara as reference group.