The safety of St. John's wort (Hypericum perforatum) during breastfeeding.
BACKGROUND
We examined the safety of St. John's wort to nursing mothers and their infants.


METHODS
A prospective, observational, cohort study was conducted. Thirty-three breastfeeding women receiving St. John's wort (Group 1) who contacted our teratogen/toxicant counseling service regarding the safety of St. John's wort during breastfeeding were followed up between May 1999 and April 2001. These women were compared with 101 disease-matched (Group 2) and 33 age- and parity-matched nondisease controls (Group 3). Information collected included maternal and neonatal demographics, breastfeeding duration, use of St. John's wort, maternal and infant adverse events, infant weight over the first year of life, and whether or not the mother experienced a decrease in lactation.


RESULTS
There were no statistically significant differences found in maternal or infant demographics or maternal adverse events. Whereas only 1 infant each in Groups 2 and 3 was reported to be colicky, there were 2 cases of "colic," 2 of "drowsiness," and 1 of "lethargy" in Group 1 (p <.01; Group 1 vs. Group 2, p <.01; Group 1 vs. Group 3, p =.20). Although 3 of these women in Group 1 consulted their doctor, specific medical treatment was not required. No significant difference was observed in the frequency of maternal report of decreased milk production among the groups, nor was a difference found in infant weight over the first year of life.


CONCLUSIONS
These results provide a framework for the management of breastfeeding women receiving St. John's wort.
Lee
Amy
A
Division of Clinical Pharmacology and Toxicology, The Hospital for Sick Children, Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada.
Minhas
Ravinder
R
Matsuda
Noriko
N
Lam
Michael
M
Ito
Shinya
S
D000928:Antidepressive Agents / Q000009:adverse effects / Q000627:therapeutic use; D001724:Birth Weight; D001942:Breast Feeding / Q000009:adverse effects; D002657:Child Development / Q000187:drug effects / Q000502:physiology; D015331:Cohort Studies; D003866:Depressive Disorder / Q000188:drug therapy / Q000628:therapy*; D005260:Female; D005865:Gestational Age; D006801:Humans; D020902:Hypericum / Q000009:adverse effects* / Q000378:metabolism; D007223:Infant; D007774:Lactation / Q000187:drug effects / Q000502:physiology; D018811:Maternal Exposure; D008431:Maternal-Fetal Exchange; D008895:Milk, Human / Q000187:drug effects / Q000502:physiology; D008517:Phytotherapy / Q000009:adverse effects*; D028321:Plant Preparations / Q000009:adverse effects* / Q000627:therapeutic use*; D011247:Pregnancy; D011248:Pregnancy Complications / Q000188:drug therapy / Q000628:therapy
D000928:Antidepressive Agents; D028321:Plant Preparations