Table 2.

Breast-feeding duration in relation to weight retention at 6, 18 and 36 months postpartum, Norwegian Mother and Child Cohort Study (MoBa)

	Sample at 6 months (n 49 675)	Weight retention at 6 months (kg)		Sample at 18 months (n 27 187)	Weight retention at 18 months (kg)		Sample at 36 months (n 17 343)	Weight retention at 36 months (kg)
	%	Mean	sd	%	Mean	sd	%	Mean	sd
Full breast-feeding
0 month	13·2	2·53	5·63	12·5	1·19	6·12	12·3	1·91	6·66
1 month	6·1	2·16	5·38	5·8	1·06	5·83	5·6	2·05	6·65
2 months	9·3	1·69	5·07	8·8	1·16	5·54	8·4	1·94	6·12
3 months	27·3	1·06	4·74	26·9	0·87	4·79	27·0	1·62	5·39
4 months	28·1	0·68	4·32	29·2	0·71	4·44	29·7	1·55	4·99
5 months	14·2	0·56	4·43	14·8	0·35	4·45	15·1	1·35	5·03
6 months	1·8	0·39	4·45	1·9	−0·10	4·73	1·9	1·16	4·55
Any breast-feeding†
0 month	3·3	2·68	6·29	3·4	1·25	7·11	3·2	1·93	6·86
1 month	2·4	2·78	6·17	2·4	1·16	6·31	2·4	2·14	7·23
2 months	3·1	2·95	5·68	3·0	0·95	6·41	3·0	1·98	7·29
3 months	3·6	2·76	5·44	3·6	1·23	6·11	3·4	1·82	7·10
4 months	2·9	2·59	5·31	2·9	1·61	5·39	2·7	1·89	6·79
5 months	2·7	1·99	5·31	2·5	1·18	5·72	2·5	1·79	6·57
≥6 months‡	82·0	0·87	4·55	–	–	–	–	–	–
6–8 months	–	–	–	16·1	1·08	5·13	15·7	1·72	5·61
9–11 months				26·1	0·82	4·45	26·3	1·58	5·12
12–14 months	–	–	–	21·9	0·61	4·49	22·5	1·42	5·10
15–18 months	–	–	–	18·0	0·36	4·65	18·3	1·65	4·94

†Any breast-feeding denotes both full and partial breast-feeding up to 6 months and partial breast-feeding beyond 6 months.

‡In total, 40 237 (81 %) women breast-fed for at least 6 months. Weight retention at ≥6 months postpartum is here shown for these women jointly.