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Pregnancy & Breastfeeding Resources
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Current Studies at Motherisk
Neurodevelopment of Children Exposed in-Utero to Chemotherapy for Maternal Breast Cancer (Dr. I Nulman)
Diclegis Surveillance Program Study
Diclectin Surveillance Program Study
Study seeks women between 4 and 12 weeks in their pregnancy with morning sickness (NVP)
Pregnancy in Women with Multiple Sclerosis
Environmental Exposures and Children's Health
Alcohol Use during Pregnancy
Control of Hypertension in Pregnancy Study
Folic Acid Before and During Pregnancy
Lamisil in Pregnancy
Meridia in Pregnancy
Autoimmune Diseases in Pregnancy Project
Breastfeeding and Drugs
Though many drugs are quite safe for a mother to take while nursing her child there are several agents for which safety during breast-feeding is not well-defined and may be a risk to the infant. Drugs that are contraindicated or should be used with caution by lactating women are described here.
Drugs Usually Contraindicated While Breastfeeding
Antineoplastics and Immune Suppressants
Even if small amounts of the drug were to be excreted into milk, the inherently toxic nature of these medications warrants caution with their use.
Due to the dopaminergic activity of the ergot alkaloids they may have the ability to suppress prolactin and hence lactation. If breast-feeding is to be considered, milk volume must be monitored in mothers. Bromocriptine is used therapeutically to prevent lactation and is therefore contraindicated in nursing mothers. Short term, low dose therapy with ergonovine and methylergonovine does not cause a risk to the infant. However, methylergonovine would be the preferred choice of the two because is does not have prolactin lowering tendencies. Ergotamine is also able to affect milk secretion and is not a preferred choice while nursing because of the risk of ergotism in the infant. Signs of toxicity in the infant include vomiting, weight loss and weak pulse.
Infants should be closely monitored if breast-fed during maternal gold therapy as the exact effect on infants is not known at this time. Reported milk levels vary widely and aurothiomalite has been measured in both urine and plasma of infants.
Iodine containing compounds are not generally recommended during breast-feeding. Iodine readily gains access to breast milk and can lead to hypothyroidism in the infant.
Breast-feeding during maternal lithium therapy is generally thought to be contraindicated because lithium has been found to attain concentrations in the milk of up to 40% of the maternal weight adjusted dose. Moreover, the excretion of lithium in milk appears to vary a great deal among patients. Since some women will have relatively low excretion of lithium into their milk, and breast-feeding can be extremely beneficial to a manic depressive mother it seems quite reasonable to initiate breast-feeding. It is recommended that infants' serum lithium concentrations be monitored and the infant be observed for signs of toxicity. Breast-feeding may be continued as long as infants' blood levels remain well below therapeutic concentrations and the infant shows no signs of toxicity.
Radioactive materials are contraindicated while breast-feeding, in order to avoid excess infant exposure to radioactivity. Once radioactivity is cleared from the mother's body, however, breast-feeding can be resumed. The length of time of breast-feeding interruption will vary with each radioisotope used depending on radioactive decay and elimination by the mother. Motherisk can be consulted regarding this length of time.
Social Drugs and Drugs of Abuse
Alcohol freely distributes into milk and will be ingested by nursing infants. Moderate, occasional alcohol consumption in not likely to pose a problem to the infant, but heavy alcohol consumption is to be avoided. Ideally nursing should be withheld temporarily after alcohol consumption; at least two hours per drink to avoid unnecessary infant exposure. Side effects reported in infants include sedation and impairment of motor skills.
Cigarette smoking is not recommended in nursing mothers. Nicotine and its major metabolite are detectable in milk. Smoking should be avoided while breast-feeding because it has been associated with infantile colic, lowered maternal prolactin levels and consequently, earlier weaning.
Street drugs can be very potent such that even very small amounts can have pharmacological activity and adverse effects on the infant. It is suggested that breast-feeding be at least temporarily delayed after maternal use of these agents and caution should be used to avoid infant exposure to smoke fumes. Infants may experience toxicity after maternal cocaine use,and marijuana use has been associated with slower motor development at one year of age.
Myla Moretti, Motherisk
Breastfeeding and the use of Antidepressants
Myla Moretti: J Popul Ther Clin Pharmacol Vol 19(3):e387-e390; October 11, 2012. Review
Neonatal benzodiazepines exposure during breastfeeding.
Kelly LE, Poon S, Madadi P, Koren G.: J Pediatr. 2012 Sep;161(3):448-51. doi: 10.1016/j.jpeds.2012.03.003. Epub 2012 Apr 14.
Cyclosporine and lactation: when the mother is willing to breastfeed.
Osadchy A, Koren G: Ther Drug Monit. 2011 Apr;33(2):147-8. doi: 10.1097/FTD.0b013e318208e3a4.
Update on antidepressant use during breastfeeding
Lauren Chad, MD, Anna Pupco, MD, Pina Bozzo, Gideon Koren, MD FRCPC FACMT
Maternal cocaine use during breastfeeding
Alex M. Cressman, M.Sc., Gideon Koren, MD, FRCPC, FACMT, Anna Pupco, MD, Eunji Kim, MScCH, Shinya Ito, MD, FRCPC and Pina Bozzo
Health Canada advisory on domperidone
Pina Bozzo, Gideon Koren, MD, FRCPC, FACMT and Shinya Ito, MD, FRCPC
Guidelines for maternal codeine use during breastfeeding
Parvaz Madadi, PhD, Myla Moretti, MSc, Nada Djokanovic, MD MSc, Pina Bozzo, Irena Nulman, MD FRCPC, Shinya Ito, MD FRCPC and Gideon Koren, MD FRCPC FACMT
Pharmacologic treatment of hyperthyroidism during lactation
Miguel Marcelo Glatstein, MD, Facundo Garcia-Bournissen, MD, Norberto Giglio, MD, Yaron Finkelstein, MD and Gideon Koren, MD FRCPC FACMT
Use of hypoglycemic drugs during lactation
Miguel Marcelo Glatstein, MD, Nada Djokanovic, MD MSc, Facundo Garcia-Bournissen, MD, Yaron Finkelstein, MD and Gideon Koren, MD FRCPC FACMT
Methadone exposure during lactation
Miguel Marcelo Glatstein, MD, Facundo Garcia-Bournissen, MD, Yaron Finkelstein, MD and Gideon
Lead exposure during breastfeeding
Jacquelyn Choi, Toshihiro Tanaka, MD, Gideon Koren, MD FRCPC and Shinya Ito, MD FRCPC
Breastfeeding and radiologic procedures
Jack Newman MD FRCPC
Marijuana use and breastfeeding
Josephine Djulus, MD Myla Moretti, MSC Gideon Koren, MD, FRCPC
Is it all right to drink a little during pregnancy?
Gideon Koren, MD, FRCPC Daniella Caprara, MSC Daphne Chan, PHD Sheila Jacobson, MD Kelly Porter
Do silicone breast implants affect breastfeeding?
Gideon Koren, MD, FRCPC; Shinya Ito, MD
Anticonvulsants and breast feeding: a critical review. Review.
Bar-Oz B, Nulman I, Koren G, Ito S: Paediatr Drugs. 2000 Mar-Apr;2(2):113-26.
Drug therapy for breast-feeding women.
Ito S: N Engl J Med. 2000 Jul 13;343(2):118-26.
Choice of breastfeeding and physicians' advice: a cohort study of women receiving propylthiouracil.
Lee A, Moretti ME, Collantes A, Chong D, Mazzotta P, Koren G, Merchant SS, Ito S: Pediatrics. 2000 Jul;106(1 Pt 1):27-30.
Breastfeeding anaphylaxis case study.
MacDonell JW, Ito S: J Hum Lact. 1998 Sep;14(3):243-4
Breast-feeding and maternal drug use. Review.
Bailey B, Ito S: Pediatr Clin North Am. 1997 Feb;44(1):41-54.
Breast-feeding and maternal drug use. [Review] [48 refs]
Bailey B, Ito S: Pediatric Clinics of North America. 44(1):41-54, 1997 Feb.
Maternal noncompliance with antibiotics during breast-feeding.
Ito S, Koren G, Einarson TR: Ann Pharmacother 27: 40-42, 1993.
A novel index for expressing exposure of the infants to drugs in breast milk.
Ito S, Koren G: Br J Clin Pharmacol 38: 99-102, 1994.
Initiation and duration of breast-feeding in women receiving antiepileptics.
Ito S, Moretti M, Chu M, Koren G: Am J Obstet Gynecol, 172: 881-886, 1995.
Acyclovir excretion in human breast milk
Taddio A, Klein J, Koren G: Ann Pharmacother 28: 585-587, 1994.
Morphine excretion in breastmilk and resultant exposure in a nursing infant.
Robieux I, Koren G, Wandenberg H, Schneiderman J: J Clin Toxicol 28: 365-370, 1990.
Excretion of fluoxetine and its metabolite in human breast milk
Taddio A, Ito S, Koren G: J Clin Pharmacol 36: 42-47, 1996.
Disposition of ketoconazole in human milk
Moretti M, Ito S, Koren G: Am J Obstet Gynecol 173: 1625-1626, 1995.
Effect of counseling on maternal reporting of adverse effects in nursing infants exposed to antibiotics through breast milk.
Taddio A, Ito S, Einarson T, Leeder JS, Koren G: Reprod Toxicol 9: 153-157, 1995.
Estimation of neonatal exposure after accidental ingestion of lufenuron in a breastfeeding mother.
Bar-Oz B, Ito S, Parks V, Maurer MP, Koren G: J Hum Lact 2000 Aug;16(3):229-30
Alcohol and breastfeeding: calculation of time to zero level in milk
Ho E, Collantes A, Kapur BM, Moretti M, Koren G: Biol Ne, 2001; 80: 219-22.