Impaired Breastfeeding or Lactation After SCI

Impaired breastfeeding and/or lactation typically occurs because of mechanical (e.g., holding and positioning the infant, latching onto the breast, nipple shape) and physiological (e.g., lactation, neurohormonal reflexes) elements.

Milk production and ejection depend on hormonal and neural stimulation. Impaired breast innervation, such as in SCI, can result in reduced afferent input to the pituitary gland. Lactation is disrupted, secondary to reduced prolactin (PRL) and oxytocin production. The breast is innervated by nerves originating from T1-5 of the spinal cord. Therefore, injuries at or above T6 can result in reduced afferent feedback that disrupts the let-down reflex, and a lack of sympathetic nervous system feedback that can compromise the myoepithelial cell contraction in breast tissue that is critical for milk ejection (Halbert 1998; Liu & Krassioukov 2013; Craig et al. 1990). Depending on motor completeness of injury, mothers injured above T6 are also likely to have more significant mobility impairments, which can add a mechanical obstacle to breastfeeding.

Discussion

The majority of the results found that level of SCI and subsequent hormonal and afferent disability accounts for at least some proportion of breastfeeding and lactation disruption. Of women with high-level SCI, 78% reported insufficient milk production or ejection as a problem while only 35% of women with injuries below T6 reported the same (Holmgren et al. 2018). Another cross-sectional study found that 29 out of 47 women (62%) chose to breastfeed, of whom 6 experienced problems, 4 reported insufficient milk, 1 had issues with clogged milk ducts and 1 woman’s baby was allergic to her milk (Charlifue et al. 1992).

Though Berezin et al. (1989) found that higher lesions (T4, T6) were associated with augmented PRL levels and more severe galactorrhea, a more recent study found that hyperprolactinemia was not correlated with SCI or galactorrhea. High PRL values (52 ng/mL compared to <25 ng/mL) and galactorrhea were found (Faubion & Nader 1997), though values normalized after bromocriptine treatment. Conversely, several case studies reported that even women with high-level SCI experience let-down or can induce it psychologically using mental imaging or pharmacologically with galactagogues (Cowley et al. 2005). These studies provide mechanistic insight into milk production after SCI that may lead to future development of treatments or management techniques for decreased milk production in mothers with SCI.

The highest quality longitudinal study (Rutberg et al. 2008) had mixed results. Hyperprolactinaemia was found in women of childbearing age (n = 9) but not in those of menopausal age (n = 7) and was strongly associated with amenorrhea in 6 women of childbearing age within 6 months of injury. Another case series study found that 4 women with SCI at or above T6 noted a decrease in milk production 6 weeks postpartum. Women with low SCI did not report any lactation difficulties (Craig 1990).

During pregnancy, PRL levels are elevated due to increased estrogen production, PRL secretion, and PRL receptor expression in the hypothalamic nuclei (Berezin et al. 1989; Boyd 1978; Grattan et al. 2001). However, none of the 16 women in total experienced galactorrhea, even if PRL levels were high. Although lactation dysfunction in breastfeeding women is more severe with SCI at or above T6, it is unclear whether severity of galactorrhea is also SCI level-dependent.

Conclusion

There is level 2 evidence (Rutberg et al. 2008) that hyperprolactinaemia strongly associated with amenorrhea in women of childbearing age within 6 months of injury and that transient increase in PRL in this population can be attributed to stress response rather than pituitary trauma.

There is level 4 evidence that SCI at or above T6 is associated with decreased milk production (Craig 1990) and higher galactorrhea, amenorrhea, and PRL levels (Berezin et al. 1989) than in populations with lower injury points.

There is level 4 evidence that women with SCI are able to elicit a letdown reflex, either naturally (Robertson et al. 1972), or through mental imaging, oxytocin, and nasal sprays (Cowley 2005).

There is level 5 evidence (Holmgren et al. 2018) that women with high-level injury had insufficient milk production or ejection, that duration of breastfeeding was short, and that there was greater difficulty in positioning for breastfeeding.