Use of tocolytics: what is the benefit of gaining 48 hours for the fetus?

Abstract

Preterm birth remains one of the serious problems in perinatal medicine and is associated with an increased risk of neonatal complications and long‐term morbidity. Although each day that delivery is delayed between 22 and 28 weeks of gestation increases survival by 3%, since most spontaneous preterm labour occurs between 28 and 34 weeks of gestation, this is of secondary concern; the primary goal of delay is to improve the function of certain systems in the fetus and to balance the risks of a hostile intrauterine environment with the complications of extrauterine preterm life. Although there is a lack of definitive evidence that tocolytic drugs improve outcome following spontaneous preterm labour and preterm birth, there is ample evidence that tocolysis delays delivery for long enough to permit administration of a complete course of antepartum glucocorticoids and to facilitate in utero transfer to a tertiary care unit where neonatal care will be optimal. Both these measures have been associated with improved outcomes; antepartum glucocorticoids reduce the incidence of respiratory distress syndrome, intraventricular haemorrhage, periventricular leucomalacia and necrotising enterocolitis, and in utero transfer is associated with decreased morbidity and mortality and less hospital‐based intervention compared with postnatal transportation. Consequently, women who are more likely to benefit from tocolysis are those at early gestational ages, those needing transfer to a hospital that can provide neonatal intensive care and those who have not yet received a full course of antepartum glucocorticosteroids. In these cases, delaying labour for at least 48 hours with drugs such as atosiban should be considered, since it offers clear advantages for the fetus.

Intensity of Perinatal Care for Extremely Preterm Infants: Outcomes at 2.5 Years

“…Perinatal activity scores were calculated for each health care region on the basis of the frequency of obstetric and neonatal interventions. Some interventions included in the scores (antenatal steroids, 3 surfactant replacement, 4 or delivery at a level III center 5 ) are known to improve outcome, whereas other interventions (eg, cesarean delivery 39 and tocolysis 40 ) may have more questionable effects. The score aimed to reflect overall willingness to intervene actively on behalf of the compromised fetus or infant, not to evaluate the effect of individual interventions.…”

Antenatal maternal corticosteroid administration and markers of oxidative stress and inflammation in umbilical cord blood from very low birth weight preterm newborn infants

“…Dados da Rede Brasileira de Pesquisas Neonatais, entre 2006 e 2010, à época, com oito centros participantes, apontam taxas menores de utilização de corticosteroide antenatal, variando entre 51 e 57% 17 . Tal uso, nessa instituição, tem sido possível graças ao empenho da equipe de obstetrícia local em oferecer tal tratamento a toda gestante com possibilidade de parto prematuro antes de 34 semanas de gestação, associado ou não ao uso de tocolíticos [18][19][20] .…”

Prevention of Preterm Labour: 2011 Update on Tocolysis

“…Management with tocolytic drugs aims to stop uterine contractions and to prevent neonatal risks associated with prematurity by in utero transfer of the pregnant patient in a tertiary specialized centre and by corticosteroids administration [1, 2, 7]. …”

“…It gives the opportunity to administrate corticosteroids for preventing neonatal risks associated with prematurity [5–7]. …”