From the Research
Oxytocin antagonists, such as atosiban, are a viable treatment option for preterm labor, with a similar efficacy to beta-adrenoceptor agonists but with fewer adverse effects 1. The primary oxytocin antagonist used clinically is atosiban, which is administered intravenously to delay preterm labor.
- A typical regimen begins with a 6.75 mg bolus dose, followed by 18 mg/hour for 3 hours, then 6 mg/hour for up to 45 hours.
- The maximum treatment duration should not exceed 48 hours. Atosiban works by competitively binding to oxytocin receptors in the uterine muscle, preventing oxytocin from attaching and thereby reducing contractions.
- This medication is generally well-tolerated with minimal side effects, primarily nausea, vomiting, headache, and dizziness. However, it's essential to consider the potential risks and benefits, as some studies have reported an increase in infant deaths and preterm births with atosiban use, particularly at gestational ages less than 28 weeks 2, 3. In contrast, other studies have found atosiban to be effective in prolonging pregnancy for up to 7 days in women with preterm labor at a gestational age of 28 weeks or more, with a low rate of maternal-fetal adverse effects 4. The most recent and highest-quality study suggests that oxytocin receptor antagonists, such as atosiban, may not be superior to other tocolytic agents in terms of efficacy or infant outcomes, but they are associated with fewer maternal side effects 2. Therefore, the decision to use oxytocin antagonists should be made on a case-by-case basis, taking into account the individual patient's risk factors and medical history. Before administering any tocolytic, clinicians should confirm that delaying delivery is appropriate and rule out contraindications such as chorioamnionitis, severe preeclampsia, or fetal distress.