Greetings All, 

The nipple shield review from 2010, as provided by [log in to unmask], appears to have a paywall.  The following link should provide open access:  

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3014757/

Donna Geddes and colleagues have an important new nipple shield study out, although its title does not reflect a significant finding in their study:  the comparison group (who reported no breastfeeding difficulties) had a marked decrease in nutritive sucking and milk transfer, dropping from 63 ml vs 31ml.  In this comparison group (with no reported breastfeeding problems), nipple shield use was randomised.  

Title:  Nipple shield use does not impact sucking dynamics in breastfeeding infants of mothers with nipple pain.

In: European Journal of Pediatrics (2021).  Published 14 January 2021.  https://doi.org/10.1007/s00431-020-03901-3

Authors:  Coentro, VS, Perrella, S.L., Lai, C.T. et al. 

Abstract: "Nipple shields (shield) may reduce pain during breastfeeding, but the impact on infant sucking dynamics is not known. We examined the effects of shield use on sucking dynamics, milk removal and nipple pain in two groups of breastfeeding dyads: pain group (PG): shield used for nipple pain; comparison group (CG): no breastfeeding difficulties. Twenty PG (6 ± 4 weeks postnatal) and 28 CG dyads (8 ± 6 weeks postnatal) attended 2 monitored breastfeeding sessions with shield use randomised. Within-subject outcomes were compared. PG: shield use did not affect intra-oral vacuum (peak p = 0.17, baseline p = 0.59), sucking frequency (p = 0.20) or milk transfer (40 mL vs 48 mL, p = 0.80; percentage of available milk removed (PAMR) 55% vs 57%, p = 0.88), and reduced McGill pain scores (p = 0.012). CG: shield use increased non-nutritive sucking (10% more, p = 0.049), and reduced nutritive sucking (18% less, p = 0.017) and milk transfer (63 mL vs 31 mL p < 0.001, PAMR 65% vs 36% p < 0.001). For both groups, feeding duration increased by 2 min (p < 0.0001) and non-nutritive portions of the feed increased with shield use.  Conclusion: Nipple shield use improved maternal comfort and did not impact milk removal or sucking strength in PG, but significantly reduced milk transfer and nutritive sucking in CG."

Abstract only:  https://link.springer.com/article/10.1007/s00431-020-03901-3

My notes:  In the pain group (mothers reporting nipple pain and using nipple shields to help ameliorate nipple pain), nipple shield use was reported as not affecting milk transfer, although overall transferred volumes were notably lower in the pain group (40ml vs 48ml) than the overall volumes in the comparison group (63ml vs 31ml).  

Only two breastfeeding sessions were observed and measured, a limitation in the study from my perspective of motor learning toward motor control.  In-session learning (during active practice sessions) and between-session learning require much more than two active practice sessions for any individual of any age to build a robust state of motor memory.  Early motor memories are particularly fragile, but become gradually more robust with the repetition of practice that is specific to the task.  The repetition of task-specific practice is necessary in building increasingly greater motor control toward a high level of skill acquisition and the robust state of motor memory, termed "consolidation."  

In the pain group, how long had those mothers been wearing NSs, as compared to the comparison group (where those who used nipple shields as well as those who did not wear nipple shields were randomised)?  If the pain group had been wearing nipple shields longer than the comparison group (in which nipple shield use was randomised and likely introduced for this study), this may account for the lower amounts transferred in the pain group, even though the abstract states that nipple shield use did not affect milk transfer in the pain group.  To make a late-night generalization at this 3:45am hour, approximately 1/3 less milk transferred by one group (the pain group) as compared to the other group (the comparison group) appears to be significant.  My apologies for not specifying this in the manner of data analysis - - it's too late to competently address that!  

If at all possible, I would like to propose a Lactnet question & answer session or thread with the study authors to gain better insight into the differences in milk transfer between the two groups (full text would be much appreciated).  My interpretation may be limited by reading the abstract in the wee hours when fatigued, and I do not have full text at my fingertips.  It would be an honor to communicate with these researchers about their most recent work.  

With best regards,

Debbie

Debra Swank, RN BSN IBCLC
Program Director
More Than Reflexes Education
Elkins, West Virginia USA
http://www.MoreThanReflexes.org    

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