Progestational agents for the prevention of preterm birth.

Abstract In a risk/benefit analysis, currently the use of PAs used in women with a previous history of PTB appears to be worthwhile though the impact on the PTB rate may be minor since 80-90% of women who deliver preterm have no past history. PTB is a heterogeneous condition. With the exception of extremes of gestational age, PTB is due in equal parts to SPTL, preterm prelabour rupture of the membranes (PPROM) and elective PTB for fetomaternal indications. The assessment of the use of PAs to prevent PTB should only relate to previous and subsequent SPTL and not to PTB due to fetomaternal indications.