Letter to the editor

Editor, – Following concerns expressed in Australian Prescriber1 regarding the information available about the passage of budesonide into breast milk, your readers may be interested to learn of some tangentially related data that have recently become available. Good asthma control in pregnancy is vital for both mother and child as the known risks of uncontrolled asthma are far greater than the known risks to both from asthma medications.2 It is known from previous studies that mother and baby may both do badly if the mother's asthma is poorly controlled.3,4

A new study5 from the University of Lund, Sweden, reviews 2014 infants whose mothers stated they had used inhaled budesonide during early pregnancy. The infants were identified through the Swedish birth registry, which covers nearly all of the 100 000 births a year that take place in Sweden and contains computerised records of the paediatric examination of the new born. Since 1 July 1994, it has stored information on self-reported drug use by women in early pregnancy. The information is obtained by asking the woman at her first antenatal visit (usually about week 10 after the last menstrual period) if she has used any drugs during pregnancy and, if so, the name of the drug. If possible, the dose and week of use are also recorded. The study does not provide any dosage information.

Although a few children in the study (3.7%, 95% confidence interval 2.9-4.6)were born with minor congenital abnormalities, analysis of the results indicates that their mother's use of inhaled budesonide was not related to this outcome. A very similar rate of abnormalities (3.5%) occurred in all children born in Sweden in 1995-1997. There was no increase in the expected number of infants with congenital cardiac defects (17 vs. 17-18 expected), and the majority of the defects were mild.

The investigators concluded that `Even though a specific teratogenic effect of use of budesonide in early pregnancy cannot be ruled out, it is unlikely that a clinically significant teratogenic effect exists'.

Susan Parker
Manager, Customer Service and Information
Astra Pharmaceuticals Pty Ltd
North Ryde, NSW


  1. Drug distribution in human milk. Aust Prescr 1997;20:35-40.
  2. National Institutes of Health. National Heart, Lung and Blood Institute. Report of the Working Group on Asthma and Pregnancy. http://rover.nhlbi.nih.gov/nhlbi/lung/asthma/prof/astpreg.txt
  3. Bahna SL, Bjerkedal T. The course and outcome of pregnancy in women with bronchial asthma. Acta Allergol 1972;27:397-406.
  4. Schatz M. Asthma during pregnancy: inter relationships and management. Ann Allergy 1992;68:123-33.
  5. Kallen B, Rydhstroem H, Aberg A. Congenital malformations after the use of inhaled budesonide in early pregnancy. Obstet Gynecol 1999;93:392-5.

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