Table 1 Characteristics of included studies

Bunik 2010

Single urban hospital in Colorado, US.

341 (I = 161, C = 180).

Postpartum (2w)

AB = 1 m, 3 m, 6 m

AB = ‘Any breastfeeding’, including ‘Predominant breastfeeding’ (< 4 oz formula daily)

TC

E

Daily educational calls from nurses using predetermined script addressing potential physical problems, benefits of breastfeeding, milk storage and alternative feeding and maternal health.

Efrat 2015

Five community health clinics in Los Angeles, US

289 (I = 146, C = 143)

Antenatal (four calls during third trimester)

Postpartum (6 m)

EB = 1 m, 3 m, 6 m

AB = 1 m, 3 m, 6 m

EB = ‘baby never received water, formula, folk remedies, or other foods’ since birth

AB = At least once since

birth, infant received water, formula, folk remedies or another food

TC

E

Four prenatal calls and seventeen postpartum calls by lactation educators.

Fiks 2017

Two obstetric clinics in Philadelphia, US

87 (I = 43, C = 44)

Antenatal (2 m)

Postpartum (9 m)

EB = 6 m

AB = 6 m

EB = Currently exclusively breastfeeding (undefined)

AB = Ever breastfed (undefined)

Complex– multi-component interactive online group

C

Facilitated Facebook group of 7–13 mothers with online activities for 11 m, including weekly educational videos and psychologist led online support groups.

Martinez-Brockman 2018

Health centre, teaching hospital and two community agencies in Connecticut US

174 (I = 94, C = 80)

Antenatal (from 28w)

Postpartum (3 m)

EB = 3 m

AB = 3 m

EB = Consumption of only breastmilk

AB = ‘Partial breastfeeding’ where infant received ‘breastmilk and formula but no solids. ‘

TM

E

Routine ‘Loving Support’ peer counselling alongside scheduled

TM (< 160 characters).

Palacios 2018

4 WIC clinics in Hawaii (HI) and 2 in Puerto Rico (PR)

202 (I = 102, C = 200)

Antenatal and Postpartum

Total duration = 4 m

AB = 3 m

EB = Consumption of only breastmilk

AB = Partial breastfeeding (undefined).

TM

E

18 w of bidirectional weekly TM (35–50 words).

Pugh 2002

Urban hospitals, US

41 (I = 21, C = 20)

Postpartum (6 m)

EB = 3 m, 6 m

AB = 1 m, 3 m, 6 m

EB = ‘Exclusive (undefined)

AB = Nonexclusive breastfeeding (undefined)

TC

PS

Daily visits from a nurse whilst in hospital and three home visits (1,2 and 4w postpartum).

Biweekly telephone support from a community-based peer counsellor for 8w, then weekly for four more months.

Pugh 2010

Two urban hospitals in

United states

328 (I = 168, C = 160)

Postpartum (6 m)

AB = 3 m, 6 m

AB = ‘Infant receiving breast milk within the last 24 h’

TC

PS

Daily hospital visits by support team until discharge, followed by three 60 min home visits within a month.

Minimum biweekly TC for 6 m by a peer counsellor and 24 h nurse access through telephone helpline.

Reeder 2014

Two rural and two urban clinics, Oregon, US

1948 separated into three arms (intense = 625, low intensity = 625, C = 635).

Antenatal (2 calls)

Postpartum (low intensity = 2w, high intensity = 4 m)

EB = 1 m, 3 m, 6 m

AB = 1 m, 3 m, 6 m

EB = Breastfeeding and not using formula.

AB =Formula or solids introduced to child’s diet

TC

PS

Peer councillor support with two intervention intensities:

Low intensity = 4 scheduled postpartum TC

High intensity = low intensity plus 4 additional calls 1,2,3 and 4 m after delivery.

Srinivas 2015

Single urban antenatal clinic, US

120 (I = 50, C = 53, lost at 1 m = 17)

Postpartum (4 m)

EB = 1 m, 6 m

AB = 1 m, 6 m

EB = ‘Only breastfeeding or breast milk feeding since birth’

AB = Infant started breastfeeding but not receiving exclusively breast milk.

TC

PS

Peer counselling mainly provided through phone calls.

Contact scheduled once antenatally, within 5 days of delivery, weekly for 4w, biweekly between 4-12w and once at 4 m.