Introduction:
Maternal medication intake may be a significant impediment to meeting breastfeeding goals^1-3. In this study we sought to classify the medications used by lactating women according to the risk in breastfeeding.

Material and Methods:
Mothers (N=847) were recruited from five maternity hospitals located in Greece, throughout the year 2020. Data were gathered prospectively by a structured questionnaire via interview during hospitalization after childbirth and via telephone in the first, third and sixth month postpartum.

Results:
Lactating women reported overall 89 different medicines, 7 of which had some degree of discrepancy in classification with regards to breastfeeding risk between the two sources used. The results showed that, according to the Lactmed and Hale classification respectively, 63% and 56.2% of the medicines were considered compatible or probably compatible, 12.4% and 28.1% were characterized as judicious, 4.5% and 1.1% referred to medications to be avoided and finally 20.2% and 14.6% were not classified as no information was available. Meperidine, although classified as potentially hazardous pursuant to Hale, was administered as a postoperative analgesic in 0.7% of lactating women. Additionally, azathioprine (0.2%), tramadole (12.5%), ergometrine (60.3%) and cabergoline (0.2%) were also administered to mothers, which according to Lactmed should be used with caution or avoided during breastfeeding. Notably, we observed widespread administration of metronidazole (24.1%), a medicine surrounded by controversy about its compatibility with breastfeeding.

Conclusions:
Medicines that may cause an infant's sedation, decrease milk supply or have debatable safety during lactation are commonly used among lactating women. Healthcare professionals should stay updated and provide evidence-based counseling to mothers regarding medicines during lactation^4,5.