Preterm labour at 34--36 weeks of gestation: should it be arrested?

Currently, preterm labour is treated with tocolytic agents and prenatal steroids until the 34th week of gestation only. Our objective in this study was to assess this practice. Seven-year records of all preterm infants born in our institution at 34--36 weeks of gestation, were evaluated retrospectively. All babies, born in singleton well-dated pregnancies, without maternal, medical or obstetric complications, and by normal vaginal delivery, were included. Their length of hospital stay and perinatal complications were compared across gestational age groups of 34, 35 and 36 weeks. Of the 207 babies included, statistically significant reductions in the rates of respiratory distress syndrome (15.0% vs. 3.2%), nosocomial sepsis (5.0% vs. 0%) and apnoea of prematurity (11.7% vs. 2.2%), and consequently, in length of hospital stay (16 +/- 2.7 vs. 4 +/- 0.3 days) occurred between 34 and 36 weeks of gestation. The severity of respiratory distress syndrome also declined significantly. The changes were most noticeable after 35 weeks of gestation, and it was concluded that neonatal complications are still prevalent at 34 and 35 weeks. Therefore, we propose that labour should not be induced at 34 and 35 weeks of gestation and that tocolytic agents and maternal prenatal steroids may be considered in preterm labour during this period.