One aspect of the present invention relates to the use of an estrogen in the treatment of Meconium Aspiration Syndrome (MAS) in a newborn infant, said treatment comprising administering an effective amount of estrogen to said newborn infant within 7 days after birth. The present treatment offers the advantage that estrogens can be administered using non-invasive modes of administration, e.g. oral or rectal administration. Other aspects of the present invention relate to a suppository for use in newborn infants comprising at least 1 μg of estrogen and to an oral applicator comprising a container holding an aqueous liquid containing micronised estetrol and a metering dispenser for metering the liquid into the oral cavity of a newborn infant.