Combining breastfeeding and work: findings from the Epifane population-based birth cohort

Table 2 Association between women’s characteristics and time of return to work (Poisson regressions; n = 2480)

	Univariate models		Multivariate model
	IRR	95%CI	IRR	95%CI
Age
18–24 y	0.91	0.82–1.00	0.95	0.85–1.06
25–29 y	0.93	0.88–0.99	1.02	0.95–1.08
30–34 y	1		1
≥ 35 y	1.08	1.01–1.16	1.02	0.95–1.09
Birthplace
Abroad	1.23	1.13–1.35	1.10	1.01–1.20
France	1		1
Matrimonial status
Married	1		1
Unmarried	0.90	0.86–0.95	0.97	0.92–1.02
Education
Elementary / middle school	1.21	1.18–1.30	1.14	1.06–1.24
High school	1.14	1.07–1.21	1.10	1.03–1.17
University	1		1
Occupation before pregnancy
Farmers, artisans, merchants	0.83	0.67–1.04	0.77	0.62–0.65
Managers	1		1
Intermediate employees	1.13	1.06–1.20	1.10	1.03–1.17
Manual workers	1.35	1.23–1.49	1.27	1.15–1.41
Body weight status before pregnancy
Thin	1.05	0.95–1.16	1.04	0.95–1.15
Normal weight	1
Overweight	1.12	1.04–1.19	1.08	1.02–1.15
Obese	1.18	1.06–1.30	1.13	1.06–1.21
Smoking before pregnancy
No	1		1
Quit during pregnancy	0.94	0.87–1.00	1.02	0.95–1.09
Before & during pregnancy	1.11	1.03–1.19	1.13	1.06–1.21
Parity
1	1		1
2	1.26	1.19–1.34	1.23	1.16–1.30
≥ 3	1.58	1.48–1.69	1.48	1.37–1.59
BF durations
No BF	1		1
< 1 month	1.04	0.96–1.13	1.07	0.99–1.15
1–4 months	0.98	0.91–1.06	1.05	0.97–1.13
> 4 months	1.27	1.19–1.35	1.31	1.23–1.39

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