Methods of milk expression for lactating women.
BACKGROUND
Breastfeeding is important, however not all infants can feed at the breast and methods of expressing milk need evaluation.


OBJECTIVE
To assess acceptability, effectiveness, safety, effect on milk composition, contamination and costs of methods of milk expression.


METHODS
We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (21 March 2016), handsearched relevant journals and conference proceedings, and contacted experts in the field to seek additional published or unpublished studies. We also examined reference lists of all relevant retrieved papers.


METHODS
Randomised and quasi-randomised trials comparing methods at any time after birth.


METHODS
Three review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy.


RESULTS
This updated review includes 41 trials involving 2293 participants, with 22 trials involving 1339 participants contributing data for analysis. Twenty-six of the trials referred to mothers of infants in neonatal units (n = 1547) and 14 to mothers of healthy infants at home (n = 730), with one trial containing mothers of both neonatal and healthy older infants (n = 16). Eleven trials compared one or more types of pump versus hand expression and 14 studies compared one type of pump versus another type of pump, with three of these studies comparing both hand expression and pump types. Twenty studies compared a specific protocol or adjunct behaviour including sequential versus simultaneous pumping protocols, pumping frequency, provision of an education and support intervention, relaxation, breast massage, combining hand expression with pumping and a breast cleansing protocol.Due to heterogeneity in participants, interventions, and outcomes measured or reported, we were unable to pool findings for most of the specified outcomes. It was not possible therefore to produce a 'Summary of findings' table in this update. Most of the included results were derived from single studies. Trials took place in 14 countries under a variety of circumstances and were published from 1982 to 2015. Sixteen of the 30 trials that evaluated pumps or products had support from the manufacturers. The risk of bias of the included studies was variable. Primary outcomesOnly one of the 17 studies examining maternal satisfaction/acceptability with the method or adjunct behaviour provided data suitable for analysis. In this study, self-efficacy was assessed by asking mothers if they agreed or disagreed with the following statement: 'I don't want anyone to see me (hand expressing/pumping)'. The study found that mothers who were using the electric pump were more likely to agree with the statement compared to mothers hand expressing, (mean difference (MD) 0.70, 95% confidence interval (CI) 0.15 to 1.25; P = 0.01, participants = 68). Mothers who were hand expressing reported that the instructions for expression were clearer compared to the electric pump, (MD -0.40, 95% CI -0.75 to -0.05; P = 0.02, participants = 68). Descriptive reporting of satisfaction in the other studies varied in the measures used, did not indicate a clear preference for one pump type, although there was satisfaction with some relaxation and support interventions.We found no clinically significant differences between methods related to contamination of the milk that compared any type of pump to hand expression (risk ratio (RR) 1.13, 95% CI 0.79 to 1.61; P = 0.51, participants = 28), manual pump compared to hand expression, (MD 0.20, 95% CI -0.18 to 0.58; P = 0.30, participants = 142) a large electric pump compared to hand expression (MD 0.10, 95% CI -0.29 to 0.49; P = 0.61, participants = 123), or a large electric pump compared to a manual pump (MD -0.10, 95% CI -0.46 to 0.26; P = 0.59, participants = 141).The level of maternal breast or nipple pain or damage was similar in comparisons of a large electric pump to hand expression (MD 0.02, 95% CI -0.67 to 0.71; P = 0.96, participants = 68). A study comparing a manual and large electric pump, reported sore nipples in 7% for both groups and engorgement in 4% using a manual pump versus 6% using an electric pump; and in one study no nipple damage was reported in the hand-expression group, and one case of nipple damage in each of the manual pump and the large electric pump groups.One study examined adverse effects on infants, however as the infants did not all receive their mothers' expressed milk, we have not included the results. Secondary outcomesThe quantity of expressed milk obtained was increased, in some studies by a clinically significant amount, in interventions involving relaxation, music, warmth, massage, initiation of pumping, increased frequency of pumping and suitable breast shield size. Support programmes and simultaneous compared to sequential pumping did not show a difference in milk obtained. No pump consistently increased the milk volume obtained significantly.In relation to nutrient quality, hand expression or a large electric pump were found to provide higher protein than a manual pump, and hand expression provided higher sodium and lower potassium compared to a large electric pump or a manual pump. Fat content was higher with breast massage when pumping; no evidence of difference was found for energy content between methods.No consistent effect was found related to prolactin change or effect on oxytocin release with pump type or method. Economic aspects were not reported.


CONCLUSIONS
The most suitable method for milk expression may depend on the time since birth, purpose of expression and the individual mother and infant. Low-cost interventions including initiation of milk expression sooner after birth when not feeding at the breast, relaxation, massage, warming the breasts, hand expression and lower cost pumps may be as effective, or more effective, than large electric pumps for some outcomes. Variation in nutrient content across methods may be relevant to some infants. Small sample sizes, large standard deviations, and the diversity of the interventions argue caution in applying these results beyond the specific method tested in the specific settings. Independently funded research is needed for more trials on hand expression, relaxation and other techniques that do not have a commercial potential.
BEST Services, 2 Kylemore Park, Galway, Ireland.
Genevieve E
GE
Becker
Hazel A
HA
Smith
Fionnuala
F
Cooney
Lancet. 2013 Aug 3;382(9890):427-451
23746772
Indian J Pediatr. 1996 Jan-Feb;63(1):87-92
10829970
Acta Paediatr. 2004 Feb;93(2):164-8
15046267
Neonatal Netw. 1995 Dec;14(8):31-6
8552014
J Perinatol. 2012 Feb;32(2):103-10
21818062
J Fam Pract. 2002 May;51(5):439-44
12019051
J Pediatr Gastroenterol Nutr. 2004 May;38(5):484-7
15097435
J Hum Lact. 1999 Sep;15(3):209-16
10578798
Arch Dis Child Fetal Neonatal Ed. 2003 Jan;88(1):F11-4
12496220
Breastfeed Med. 2012 Apr;7(2):107-11
21740276
Pediatrics. 2010 Jul;126(1):e18-25
20566605
Zhonghua Hu Li Za Zhi. 1990 Sep;25(9):454-5
2272115
BMC Pregnancy Childbirth. 2015 Apr 02;15:81
25881251
J Perinatol. 2009 Nov;29(11):757-64
19571815
Early Hum Dev. 1994 Aug;38(2):131-8
7851306
Pediatrics. 1989 Jan;83(1):57-60
2642620
Pediatrics. 2012 Mar;129(3):e827-41
22371471
J Hum Lact. 1996 Sep;12(3):193-9
9025426
Arch Pediatr Adolesc Med. 2003 Mar;157(3):237-43
12622672
Am J Perinatol. 1991 Jan;8(1):25-7
1987962
Midwifery. 2013 Jul;29(7):794-800
23063092
Adv Neonatal Care. 2012 Apr;12(2):112-9
22469966
J Pediatr Gastroenterol Nutr. 1984 Mar;3(2):280-3
6707847
Proc Nutr Soc. 1995 Jul;54(2):401-6
8524887
J Hum Lact. 1990 Sep;6(3):132-3
2400562
Pediatrics. 1994 Dec;94(6 Pt 1):853-60
7971001
Eur J Obstet Gynecol Reprod Biol. 1998 Apr;77(2):131-9
9578268
Matern Child Nutr. 2013 Jul;9(3):425-30
22236401
Arch Dis Child Fetal Neonatal Ed. 2001 Sep;85(2):F91-5
11517200
Birth. 1999 Dec;26(4):233-8
10655829
Pediatrics. 2002 Apr;109(4):e57
11927730
Breastfeed Med. 2008 Mar;3(1):3-10
18333763
Breastfeed Med. 2011 Apr;6(2):69-75
20958105
Hum Nutr Clin Nutr. 1985 May;39(3):193-202
4019266
Breastfeed Med. 2012 Apr;7(2):112-7
21777073
Pediatrics. 1988 Jun;81(6):815-20
3368280
J Perinatol. 2013 Jul;33(7):514-9
23370606
West J Nurs Res. 2016 May;38(5):529-52
25395013
Clin Pharmacol Ther. 2008 Dec;84(6):710-4
18596681
Diabetes Care. 1994 Jan;17(1):13-9
8112184
J Pediatr. 2001 Aug;139(2):261-6
11487754
Breastfeed Med. 2015 Jul-Aug;10(6):312-7
26204125
Pediatrics. 2004 May;113(5):e435-9
15121986
Breastfeed Med. 2008 Mar;3(1):11-9
18333764
Pediatrics. 2010 May;125(5):e1048-56
20368314
Arch Pediatr Adolesc Med. 2001 May;155(5):548-53
11343496
Acta Paediatr. 2004 Apr;93(4):518-22
15188980
J Pediatr Gastroenterol Nutr. 1984;3(1):108-22
6363664
Br Med J (Clin Res Ed). 1981 Jan 10;282(6258):99-100
6779930
Am J Dis Child. 1981 Apr;135(4):340-3
7193971
J Hum Lact. 2014 Feb;30(1):41-6
24212300
Cochrane Database Syst Rev. 2015 Feb 27;(2):CD006170
25722103
Matern Child Health J. 2012 Oct;16(7):1421-30
22038565
J Perinatol. 2002 Jul-Aug;22(5):354-9
12082468
Int J Nurs Stud. 1990;27(3):257-65
2379986
Early Hum Dev. 1982 Jul;6(3):295-303
7128509
BMJ. 1990 Jan 6;300(6716):11-6
2105113
Rev Lat Am Enfermagem. 2014 Mar-Apr;22(2):277-85
26107836
BMC Pregnancy Childbirth. 2013 Nov 19;13:212
24246046
Adv Neonatal Care. 2003 Apr;3(2):76-87
12881949
Breastfeed Med. 2012 Dec;7(6):442-7
23039397
J Nurse Midwifery. 1982 May-Jun;27(3):3-8
6919579
Arch Dis Child. 1946 Mar;21:1-12
20989201
Cochrane Database Syst Rev. 2012 Mar 14;(3):CD005544
22419310
Evid Rep Technol Assess (Full Rep). 2007 Apr;(153):1-186
17764214
Pediatrics. 1999 Jun;103(6 Pt 1):1150-7
10353922
Am J Dis Child. 1985 May;139(5):483-5
3984973
J Obstet Gynecol Neonatal Nurs. 1989 May-Jun;18(3):231-6
2738757
PLoS One. 2015 Mar 06;10(3):e0119624
25747308
Arch Dis Child Fetal Neonatal Ed. 2012 Jan;97(1):F18-23
21747129
Cochrane Database Syst Rev. 2008 Oct 08;(4):CD006170
18843707
Am J Clin Nutr. 2012 Feb;95(2):498-505
22237059
Pediatr Nurs. 2008 Mar-Apr;34(2):125-30, 138
18543837
Rep Health Soc Subj (Lond). 1981;22:1-37
7268170
Trials. 2013 Dec 27;14:445
24370263
Acta Obstet Gynecol Scand. 1985;64(8):673-5
3832759
J Hum Lact. 2001 May;17(2):126-31
11847826
J Am Coll Nutr. 2012 Feb;31(1):63-9
22661628
Midwifery. 2011 Apr;27(2):209-14
19615797
Lancet. 1990 Dec 22-29;336(8730):1519-23
1979363
J Hum Lact. 2002 Nov;18(4):344-52
12449050
Lancet. 1997 Jul 19;350(9072):166-8
9250183
J Hum Lact. 2002 Nov;18(4):361-7
12449052
Lancet. 1987 Aug 8;2(8554):319-22
2886775
Int Breastfeed J. 2012 Aug 29;7(1):11
22929649
Hum Nutr Appl Nutr. 1985 Dec;39(6):426-30
4093328
Breastfeed Med. 2010 Apr;5(2):71-7
20113201
J Hum Lact. 2014 Feb;30(1):62-72; quiz 110-2
24166052
J Pediatr Gastroenterol Nutr. 1984 Mar;3(2):284-9
6538598
J Trop Pediatr. 2007 Apr;53(2):125-30
17409102
Pediatrics. 2010 May;125(5):e1162-70
20403941
J Hum Lact. 2010 Aug;26(3):258-65
20689102
J Hum Lact. 2005 May;21(2):169-74
15886342
Breastfeed Med. 2007 Jun;2(2):83-91
17661579
J Perinatol. 2012 Mar;32(3):205-9
21904296
Arch Dis Child Fetal Neonatal Ed. 2016 Nov;101(6):F502-F506
26936878
Biochem J. 1933;27(5):1400-10
16745246
J Hum Lact. 2001 Feb;17(1):9-13
11847858
Breastfeed Rev. 2006 Nov;14(3):5-9
17190014
J Clin Diagn Res. 2015 Apr;9(4):CC04-6
26023551
Oxf Rev Reprod Biol. 1985;7:118-67
3909063
Pediatrics. 1998 Sep;102(3):E38
9724686
Adv Exp Med Biol. 2004;554:321-3
15384591
Pediatr Int. 2010 Feb;52(1):39-43
19519669
Adv Neonatal Care. 2005 Apr;5(2):93-103
15806450
Breastfeed Med. 2009 Mar;4(1):17-23
19196038
Breastfeed Med. 2012 Dec;7(6):487-8
22424466
Soc Sci Med. 2011 May;72(9):1515-21
21474223
Early Hum Dev. 1982 Apr;6(2):153-9
7094853
Pediatrics. 2001 Jun;107(6):1291-7
11389245
J Hosp Infect. 1989 Jan;13(1):27-31
2564015
Int Breastfeed J. 2006 Dec 22;1:28
17184553
Alcohol. 2010 Mar;44(2):141-8
20056373
J Perinat Neonatal Nurs. 2003 Apr-Jun;17(2):150-7
12822702
Pediatrics. 2008 Oct;122 Suppl 2:S63-8
18829833
BMJ Open. 2015 May 07;5(5):e007512
25953728
Pediatrics. 1999 Apr;103(4 Pt 2):870-6
10103324
Breastfeed Med. 2015 Nov;10(9):412-5
26393901
J Hum Lact. 2005 Nov;21(4):413-20
16280557
Arch Dis Child Fetal Neonatal Ed. 2006 May;91(3):F169-74
16223754
Pediatrics. 1992 Mar;89(3):437-40
1741218
BMC Pregnancy Childbirth. 2015 Oct 20;15:268
26487378
J Hosp Infect. 2001 Dec;49(4):274-81
11740876
Br Med J (Clin Res Ed). 1983 Apr 9;286(6372):1180-1
6404380
Pediatrics. 2007 Apr;119(4):e837-42
17403827
Am J Clin Nutr. 2008 Aug;88(2):305-14
18689365
Cochrane Database Syst Rev. 2011 Dec 07;(12):CD006170
22161398
J Obstet Gynecol Neonatal Nurs. 1994 Jan;23(1):46-52
8176527
J Hum Lact. 2013 Aug;29(3):412-9
23776081
J Hum Lact. 1997 Jun;13(2):127-30
9233203
Am J Health Promot. 1995 Nov-Dec;10(2):148-53
10160049
Hum Reprod. 2001 Mar;16(3):581-3
11228232
Breastfeed Med. 2015 Mar;10(2):84-91
25659030
J Nurse Midwifery. 1993 Sep-Oct;38(5):257-66
8246081
J Hum Lact. 2003 May;19(2):179-86; quiz 87-8, 218
12744535
Adv Neonatal Care. 2014 Aug;14(4):E9-E19
25075927
Breastfeed Med. 2015 Sep;10(7):352-4
26171639
J Hum Lact. 1997 Sep;13(3):195-202
9341411
J Hum Lact. 2002 Nov;18(4):353-60
12449051
J Res Health Sci. 2012 May 29;13(1):43-7
23772006
Breastfeed Med. 2008 Sep;3(3):141-50
18778208
J Perinat Educ. 2009 Spring;18(2):13-22
20190850
J Pediatr Gastroenterol Nutr. 1984;3(1):104-7
6694039
Pediatrics. 2001 Jun;107(6):E94
11389292
J Perinatol. 2012 Oct;32(10):791-6
22222549
Pediatrics. 2008 Oct;122 Suppl 2:S25-7
18829827
Arch Gen Psychiatry. 2008 May;65(5):578-84
18458209