Table 2

Pregnancy, maternal and household characteristics for the UKMCS cohort (n=17 521)

	UKMCS: total		BF initiated		BF≥8 weeks		BF at 6 months		EBF at 6 months
Variables	n	Per cent	n	Per cent	n	Per cent	n	Per cent	n	Per cent
Total	17 521	100	11 774	67	7630	44	3768	22	226	1
Place of birth
Home birth	340	2	280	2 (82*)	228	3 (67*)	159	4 (47*)	13	6 (4*)
Hospital birth	17 181	98	11 494	98 (67†)	7402	97 (43†)	3609	96 (21†)	213	94 (1†)
Maternal age
<30	9762	56	5915	50	3307	43	1425	38	88	39
30–35	5042	27	3733	32	2684	35	1387	37	77	34
≥35	2764	16	2124	18	1638	22	956	25	61	27
Marital status
Single parent	7121	41	3904	33	2185	29	907	24	52	23
Parity
Multiparous	8596	49	5573	47	3876	51	2077	76	141	62
Primiparous	8975	51	6201	53	3754	49	1691	24	85	38
Maternal education
NVQ 1–3	9039	52	5537	47	3196	42	1329	35	75	33
NVQ 4–5	5093	29	4408	38	3377	44	1904	51	97	43
Foreign Qual.	542	3	404	3	299	4	173	5	14	6
No Qual.	2846	17	1405	12	743	10	354	9	39	17
SES
Never worked	2114	12	1308	11	817	11	1904	11	39	17
Lower	948	5	587	5	353	5	127	3	6	3
Intermediate	2929	17	2084	18	1299	17	629	17	36	16
Routine	6400	36	3461	29	1886	25	815	22	52	23
Employer	624	4	482	4	360	5	193	5	18	8
Manag./Prof.	4556	26	3852	33	2915	38	1575	42	75	33
Ethnicity
White	14 677	84	9317	79	5884	77	2838	75	141	63
Black	644	4	600	5	482	6	269	7	19	8
Asian‡	1691	9	1379	12	894	12	440	12	46	21
Other	511	3	457	4	355	5	213	6	18	8
Smoking status
Smoker	5274	30	2659	23	1320	17	454	12	26	12
Maternal alcohol consumption§
Every day	372	2	293	2	210	3	112	3	5	2
5–6×/week	353	2	304	3	224	3	124	3	2	1
<2×/week	5597	32	3910	33	2690	35	1345	36	77	34
≤2×/month	6945	40	4290	37	2575	34	1140	30	57	25
Never	4281	24	2975	25	1931	25	1047	28	85	38
Maternal BMI
<18	612	3	386	3	236	3	125	3	5	2
18–25	8691	50	5898	50	4043	53	2094	56	115	51
25–30	3920	22	2625	22	1645	22	777	21	59	26
≥30	1982	11	1316	11	753	10	355	9	22	10
Missing	2316	13	1549	13	953	12	417	11	25	11
Infant gender
Female	8523	49	5704	48	3749	49	1894	50	129	57
Gestational age (weeks)
<37	1055	6	703	6	395	5	169	5	9	4
≥37	16 274	94	10 954	94	7158	95	2859	95	211	96
Mode of delivery
SVD	12 168	69	8044	68	5311	70	2663	71	173	76
Assisted	1685	10	1196	10	751	10	340	9	11	5
Caesarean	3665	21	2533	22	1568	20	765	20	42	19

*The proportion of mothers (%) who had home birth and were still BF at the specified BF time point, of the total number of mothers who had home birth.
†The proportion of mothers (%) who had hospital birth and were still BF at the specified BF time point, of the total number of mothers who had hospital birth.
‡Indian, Bangladeshi or Pakistani nationality.
§Alcohol consumption: the reported figures are frequency of alcohol consumption (not units of alcohol consumption).
BF, breast feeding; BMI, body mass index (maternal, measured postdelivery, available for n=15 205, 87%); EBF, exclusive breast feeding; Manag., managerial; n, number of participants; Prof., professional; education level is classified according to National Vocation Qualification (NVQ) level, NVQ level 3 corresponds to a qualification of A-levels standard (school leaving examinations at 18 years of age) and level 4 is at certificate level, a qualification immediately above leaving-school level; SES; socioeconomic status: maternal employment is classified according to the National Statistics, Socio-Economic Classification,34 a five-part classification system; SVD, spontaneous vaginal delivery; UKMCS, UK Millennium Cohort Study; Qual., qualification.