Green Milk After Propofol? - Chromatography Investigates

Breastfeeding is the normal way for new mothers to feed their new born babies. It provides all the nutrients needed for infants to maintain a healthy growth and development during their initial few months or years. The World Health Organization recommends that if possible, exclusive breastfeeding up to six months of age, followed by feeding with complimentary foods up to two years is the best practice. Sometimes though things don’t go to plan. A recent report in the Canadian Journal of Hospital Pharmacy highlights one such case and it involves green breast milk.

Stomach ache to green milk

The case centres around a woman who turned up at an emergency department after suffering from stomach pains and decreased appetite for four days - with no food eaten in the previous two days. The lady in question had five children with five full-term births - the last child being born eight months previously and she was actively breastfeeding the infant 6 to 8 times daily without any problems.

The patient did not use drugs and took a daily omega-3 supplement and a multivitamin tablet. The emergency department staff ran blood tests and found nothing untoward. The diagnosis was defined as acute appendicitis and the patient had immediate surgery under general anaesthetic and the appendix was removed. The surgery was successful with no complications. But when she started to express breastmilk again twenty-two hours later - it had a green tinge.

Cause of the green tinge - propofol?

There have been reports of propofol - a drug used in general anaesthesia - changing the colour of urine to green in post-operative patients. The urine gradually returns to its normal colour over the course of a few days. But there are few reports of breast milk turning green in the scientific literature. The team tested for propofol metabolites using gas chromatography-mass spectrometry. Using chromatography to test for metabolites is discussed in the article, Capillary Electrophoresis-Mass Spectrometry for Micro-Metabolomics.

After it is administered, propofol is rapidly distributed throughout the body’s tissues. It is a highly lipophilic compound and non-water soluble. The lipophilicity favours its distribution throughout mammary tissue and subsequent build up in the lipid faction of breast milk. It is also a relatively small molecule, with a molecular mass low enough that the molecule can diffuse into breast milk.

However, the GC-MS did not detect any propofol in the green breast milk. The patient though did not breast feed until the green coloration disappeared four days after the operation. The team report that propofol can cause discoloration of biological fluids other than urine, and they have subsequently seen another case of green breast milk. The recommendation is to advise patients to be aware of the possible effects of propofol and to exhibit caution in breastfeeding with green milk.