Breast milk is undeniably the ideal natural food for babies, as it is made to meet human needs. Breast milk consists of lactose and oligosaccharides, milk fat, proteins, including secretory immunoglobulin A (IgA) and minerals.

It provides all the vitamins, proteins, fats, carbohydrates, trace elements and salts that babies need, while at the same time strengthening their immune system and their neurodevelopmental development. Breast milk is secreted into the alveoli by active transport, which includes exocytosis, reverse pinocytosis, transcytosis and transport to the nipple.

Medicines ingested by the mother are generally transferred into milk by diffusion. Only the unbound fraction of the drug is transferred into breast milk. High molecular weight, strongly protein bound and non-lipid soluble drugs are unlikely to pass into breast milk.

Drug kinetics may also affect final drug concentration, eg, drugs with long half-lives are more likely to accumulate in breast milk.

The patient with Autoimmune Rheumatic Disease should be well informed and actively participate in the treatment decisions that need to be made, before conception, during pregnancy and after delivery and regarding breastfeeding.

Breastfeeding is a natural ability

Autoimmune Rheumatic Diseases are characterized by the presence of laboratory features, autoantibodies, i.e. antibodies against the organism itself.

The coexistence of Autoimmune Rheumatic Disease (ARN) during breastfeeding may lead to the recurrence and exacerbation of ARN, due to increased pro-inflammatory effect of increased prolactin.

Low-risk medications for nursing mothers with A.R.N.

Nonsteroidal anti-inflammatory drugs (NSAIDs) are weak acids and are highly protein bound, so they pass into milk in low amounts, smaller doses of NSAIDs should be preferred, with caution for premature infants.
Hydroxychloroquine and sulfasalazine are compatible with breast-feeding. Azathioprine is excreted in breast milk in a very low amount.

Drugs of increased risk for nursing mothers with A.R.N.

MTX is excreted in breast milk, although in low concentrations. Regarding glucocorticoids, on average, less than 10% of a dose of prednisone or prednisolone is excreted in breast milk. Peak serum levels occur 1 hour after dosing and decline rapidly thereafter.

Their use during lactation

It is considered compatible, according to the American Academy of Pediatrics (AAP), if it is justified by the potential benefit to the mother’s health.
• The use of the lowest effective dose is mandatory
• Glucocorticoids (GC) for women receiving steroid doses > 20 mg/day, it is recommended to delay breastfeeding for 4 hours after ingestion.
• For women taking >40 mg of prednisone daily, it is prudent to monitor the infant for signs of adrenal suppression.
• Of the biological agents used in the treatment of A.P.N. the safest are TNFα-inhibitors. Because of their structure, they are low-risk drugs for nursing mothers with A.R.N.
• A small amount of IgG1 is secreted in breast milk and most available TNFα inhibitors contain IgG1 moieties.
• In addition to the low potential for active transport, TNFα-blockers are high molecular weight proteins and would be expected to have little diffusion into breast milk.

Frequently asked questions

1) Are there risks to breastfeeding a woman who has an autoimmune condition before pregnancy? Can breastfeeding cause an autoimmune disease?
A nursing mother faces a difficult period in her life. High prolactin levels can lead to either the development of autoimmune diseases in susceptible mothers or exacerbations of pre-existing autoimmune disorders.

2) Does breastfeeding affect the mother’s immune system?
A patient with autoimmune rheumatic disease is not going to face any problem during breastfeeding, provided that she is monitored by her Rheumatologist who will work with the Gynecologist for the best management.

3) Can breastfeeding cause a flare of Systemic Lupus Erythematosus?
In particular, patients with Systemic Lupus Erythematosus may be vulnerable to a flare-up of the disease after delivery. Postpartum lupus flares are treated similarly to those in a nonpregnant patient.

4) Is it possible to transfer autoimmune antibodies from mother to baby during breastfeeding?
It is possible to transfer autoantibodies, but also a wide range of other substances, during breastfeeding, many of which are beneficial, while others (often drug-based) can be problematic.