To assess the maternal haematological effects of betamethasone administered
in late pregnancy, an automated full blood count was performed before and
daily for 5 days after betamethasone in 25 women with a singleton pregnancy
between 23 and 33 weeks' gestation. From a mean (+/-SD) baseline level of
11.0+/-2.2 x 10(9)/L, the total white cell count increased significantly to
13.2+/-2.9 x 10(9)/L and 13.5+/-3.1 x 10(9)/L on the first and second day
after treatment respectively, returning to baseline on day 3 (p<0.0001, ANO
VA), These changes represented a mean increase in the neutrophil count of 3
5% and a mean decrease in the lymphocyte count of 23%. While there was cons
iderable intersubject variation in the extent of the changes, this study ha
s quantified the leucocytosis induced by betamethasone in late pregnancy, i
nformation that may assist with the clinical evaluation of a woman at risk
of preterm delivery.