A study, performed in Denmark (1996-2011 ), has assessed the association between use of macrolide antibiotics in mothers and infants from pregnancy onset until 120 days after birth and infantile hypertrophic pyloric stenosis ( IHPS ).
Participants were 999 378 liveborn singletons and linked individual level information on macrolide prescriptions ( maternal use during pregnancy, n=30 091; maternal use after birth, n=21 557; use in infants, n=6591 ), surgery for infantile hypertrophic pyloric stenosis, and potential confounders.
The main outcome measure was surgery for IHPS by three categories of macrolide use: in mothers during pregnancy, in mothers after birth, and in infants after birth.
880 infants developed infantile hypertrophic pyloric stenosis ( 0.9 cases per 1000 births ). Compared with infants with no use of macrolides, the adjusted rate ratio for IHPS in infants with use of macrolides during days 0 to 13 after birth was 29.8 and during days 14 to 120 was 3.24; the corresponding absolute risk differences were 24.4 and 0.65 cases per 1000 infants exposed to macrolides, respectively.
The rate ratio for maternal use of macrolides for days 0 to 13 after birth was 3.49 and for days 14 to 120 was 0.70; the corresponding absolute risk differences were 2.15 and −0.11.
The rate ratios for maternal use of macrolides during pregnancy were 1.02 for weeks 0 to 27 and 1.77 for weeks 28 to birth; the corresponding absolute risk differences were 0.01 and 0.67.
In conclusion, the treatment of young infants with macrolide antibiotics was strongly associated with infantile hypertrophic pyloric stenosis and should therefore only be administered if potential treatment benefits outweigh the risk.
Maternal use of macrolides during the first two weeks after birth was also associated with an increased risk of infantile hypertrophic pyloric stenosis.
A possible association was also found with use during late pregnancy. ( Xagena )
Lund M et al, BMJ 2014;348:g1908