Insufficient glandular tissue and breast hypoplasia

Insufficient mammary glandular tissue is a rare condition but prevalence appears to be increasing

Insufficient glandular tissue (IGT) is a rare condition, which appears to be increasing in prevalence. It may or may not be associated with certain anatomic characteristics of the breasts.

• It is unclear how much IGT results from genetic or environmental influences, resulting in aberrant mammary gland development during embryonic life, puberty, or pregnancy.

• Because of the major health system blind spots concerning clinical breastfeeding and lactation support, it is unclear how much milk production which is insufficient to meet an infant's caloric needs is impacted by insufficient glandular tissue and how much inadequate production results from poor health system support, including re fit and hold and frequent flexible breastfeeds.

In the Resource Hub, there is a clinical demonstration of a woman who had been unhelpfully diagnosed with Insufficient Glandular Tissue, and I recommend that you view this, if you haven't already.

Are there anatomic characteristics associated with mammary gland hypoplasia?

Certain anatomic characteristics of the breast are associated with a greater risk of insufficient milk production and comprise a rare developmental abnormality.

These anatomic characteristics can be labelled type 3 or type 4 breast tyes by the Huggins classification (2000), validated by Kam et al 2020. These breast types are characterized by deficiency in the circumferential skin envelope at the base of the breast, asymmetry, and herniation of fibroglandular tissue in the areolar region.

Breast hypoplasia types 3 and 4 are anatomic diagnoses. Although breast hypoplasia appears to be strongly linked with Insufficient Glandular Tissue, IGT is diagnosed retrospectively and may also be diagnosed in women who don't have anatomic breast hypoplasia.

Figure 1 Kam et al 2020. Huggin's breast type classification. Types 3 and type 4 are at increased risk of insufficient glandular tissue.

Three key points to remember about Insufficient Glandular Tissue

Here are three important points to know about IGT.

1. There is usually some breast milk production and women do not neeed to wean their baby from the breast, even if they need to supplement their baby's caloric intake.

2. Considerations of fit and hold, and frequent flexible breastfeeds, remain an essential element of clinical support.

3. Breast tissue continues to grow through each pregnancy so the next lactation experience may result in more milk production.

Huggins et al 2000 studied a case series of 34 participants with at least one of the following features

• Noticeable breast asymmetry

• A wide intramammary width (equal to 3.8 cm)

• Stretch marks on one or both breasts

• Little or no breast growth in pregnancy

• Lack of engorgement in the first week postpartum.

Huggins et al found that only one participant in the study produced all the milk necessary for her infant in the first week after birth. 85% of women with type 2, 3 or 4 breasts produced less than 50% of the milk necessary for their infants. The insufficient milk supply was then attributed to breast hypoplasia.

However, I don't consider type 2 changes germaine to Insufficient Glandular Tissue diagnosis, as the changes attributed to type 2 may in my view simply fall within the spectrum of normal breast shape variation.

Figure 3 from Kam et al 2020: where to take an intra-mammary width measurement

Intramammary width

Intramammary width is described as "area of flatness from one side to the other" and 'the line that is the vertical centre of the breasts".

Intramammary width has good intra-rater and inter-rater agreement. It appears to be a reliable measure but we don’t know if it actually helps us diagnose Insufficient Glandular Tissue. (Kam et al 2020)

Clinical implications

As health professionals, we might have some suspicions about Insufficient Glandular Tissue if we notice the woman’s breasts are widely spaced and conical, with a prominent or elevated areolar.

IGT is most often a diagnosis of exclusion retrospectively, after we have implemented all the useful strategies for increasing supply that we can.

I never measure the intramammary width, though I might privately make an estimation and clinical note. The risk with intramammary width measurement, in the absence of good evidence to suggest that measuring it helps improve outcomes, is that

• Women with petite breasts and difficult to define breast border may be inappropriately diagnosed with an abnormal anatomic feature, causing a negative perception of their bodies

• Time can be wasted in the consultation on taking a measurement that doesn't help outcomes.

I propose that we should remain reluctant to communicate to any woman that her breasts have an abnormal shape.

In type 3 and 4 cases, communicating sensitively about the heightened possibility of Insufficient Glandular Tissue because of its link with this particular anatomic configuration is important. Having type 3 or type 4 breast characteristics doesn't mean that the patient can't generate milk for her baby, and can't breastfeed.

Much more commonly, women will have trouble generating a good supply because of adversity in the first couple of weeks post-birth, when the breasts were being primed for long-term milk production.

Are exogenous factors such as endocrine disrupting chemicals relevant?

It is also unclear how exogenous factors such as endocrine disrupting chemicals impact on subsequent milk production. It has been hypothesised that a mixture of chemicals which interfere with aspects of hormone action and which can be found in plastic bottles, toys, detergents, flame retardants, food, cosmetics and pesticides may have an aetiological role. The mammary gland is particularly sensitive to endocrine disrupting chemicals.

There is no doubt that our environment increasingly contains endocrine disrupting chemicals and this is a topic which requires research evaluation. However, as clinicians it does not help (and may harm) to be looking back through a patients' history for possible exposure to endocrine disrupting chemicals. I strongly support protection of the public from exposure to these chemicals, but I consider these to have only a minor role in the complex systems which impact on development of breast tissue and result in Insufficient Glandular Tissue.

Selected references

Brown MH, Somogyi RB (2015) Surgical strategies in the correction of the tuberous breast. Clin Plast Surg 42:531–549. https://doi.org/10.1016/j.cps.2015.06.004

Huggins, K. E., Petok, E. S., & Mireles, O. (2000). Markers of lactation insufficiency: A study of 34 mothers. Current Issues in Clinical Lactation, 1, 25–35.

Kam RL, Amir LH, Cullinane M. Is there an association between breast hypoplasia and breastfeeding outcomes? A systematic review. Breastfeeding Medicine. 2021;16(8):594-602.

Kam RL, Bernhardt SM, Ingman WV, Amir LH. Modern, exogenous exposures associated with altered mammary gland development: a systematic review. Early Human Development. 2021;156:105342.

Kam RL, Cullinane M, Vicendese D, Amir LH. Reliability of markers for breast hypoplasia in the early postpartum period. Journal of Human Lactation. 2021:doi:10.1177/0890334421991071.