New Research - Oral Antibiotics and preterm labour /
rupture of membranes
Research published in the Lancet on 18 September 2008 suggested that low-dose oral antibiotics given to pregnant women to delay premature birth might cause long-term harm to their babies.
How this study relates to antibiotics prescribed against GBS
It doesn’t. Antibiotics given to mothers and babies for GBS infection are given intravenously and in large doses so that the infection is properly treated. The study published in the Lancet related to giving low-does oral antibiotics to mothers who were in threatened preterm labour, or who had preterm prelabour rupture of the membranes. The mothers had no obvious signs of infection. The study results do not apply to giving antibiotics to mothers with actual infections in pregnancy. Mothers who have evidence of infection should always be prescribed antibiotics. In such situations, antibiotics can be life saving, and with holding antibiotics can have serious consequences.
The Lancet study suggested a small increase in the absolute numbers of babies developing cerebral palsy if the mother had threatened preterm labour and was given low-dose oral antibiotics (about 1 in 60-80 babies), but not for preterm prelabour rupture of membranes, suggesting that there is something about threatened preterm labour that interacts with the antibiotics to cause the problem. For example, it might in some cases be due to “hidden” infection in the womb that is suppressed, but not eradicated, by taking low-dose oral antibiotics, thus keeping the baby in a damaging environment for longer. This effect is unlikely to apply to mothers prescribed oral antibiotics for group B Strep (GBS) in the urine, because the bugs are not in the womb and the risk from not treating an active urinary infection is substantial. The antibiotics associated with the risk (amoxicillin, erythromycin) are both broad spectrum (affecting many bacteria), unlike penicillin (which has a more targeted effect), and they were given for up to ten days (not just in labour).
If you are worried, you should speak with your midwife, GP or obstetrician.
What the study covered:
This study only included women with no sign of any infection for whom:
o labour had started early (preterm labour) and
o whose waters had broken early (premature rupture of membranes)
The mothers in the study would not usually have been given antibiotics (as the study excluded any
women who had any indication of infection). The trial was looking to establish whether oral antibiotics given in either of the situations described above would be beneficial to the baby.
The original study, published in 2001, found that oral antibiotics given to mothers in early labour and whose waters had broken was possibly beneficial in prolonging the pregnancy and reducing infection, respiratory difficulties, and abnormal brain scans in the baby. It also found that there was no benefit to the baby when the mother had oral antibiotics in preterm labour when her waters hadn’t broken,
although there was a lower occurrence of infection in the mother.
The new study found that, at age seven, children born to mothers who were given oral antibiotics for early labour (but whose waters hadn’t broken) had an increased risk of cerebral palsy. There was no
increased risk for those given oral antibiotics for early labour when their waters had broken. The reason for this difference is unknown.
In a statement, the Royal College of Obstetrician & Gynaecologists says, “These findings do not mean that
antibiotics are unsafe for use in pregnancy. Pregnant women showing signs of infection should be treated promptly with antibiotics …. Antibiotics should also therefore be used if there are indications for the prevention of maternal or neonatal infection.”
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