Clinical Question Do betamimetics...

Clinical Question

Do betamimetics (i.e., beta agonists) improve results for women with preterm labor?

Evidence-Based Answer

Treatment with betamimetics decreases the number of women with preterm labor who give birth within 48 hours, unless it does not decrease the number of births within seven days. Limited evidence proposes that treatment with beta-mimetics does not decrease perinatal death or morbidity.

Practice Pointers

Betamimetics commonly are used to decrease uterine contractions in women with preterm labor. However, they may cause discomfort and life-threatening adverse weights such as pulmonary edema and hypokalemia. Anotayanonth and colleagues identified 11 randomized controll trials of betamimetics in 1332 women with preterm labor.

Compared with placebo, the betamimetic ritodrine significantly decreased the number of women who give birth within 48 hours (23 versus 39 percent; relative risk [RR] 063; 95 percent confidence interval [CI], 053 to 075) This corresponds to a number urgencyed to treat of 6. It also reduc the risk of delivery within seven days. This benefit did not persist after the authors performed a sensitivity analysis with a random-effects model

greatest in quantity of the participants were at 32 weeks' gestation or more. Maternal adverse results included chest pain, dyspnea, tachycardia, palpitations, tremor, headache, hypokalemia, hyperglycemia, nausea and vomiting, and nasal stuffiness. The RR for cessation of treatment because of adverse terminations was 11.3 (95 percent CI, 38 to 335) There was no difference in the rate of perinatal and neonatal deaths. Treatment had no issue on neonatal morbidity such as respiratory distress syndrome cerebral palsy, and necrotizing enterocolitis. sum of two units trials comparing ritodrine with terbutaline in 183 women institute that patients who took terbutaline had a higher incidence of hyperglycemia. There was no difference in maternal or neonatal outcomes

Although no improvement in infant issues was found in this review, greatest in quantity of the trials were done before antenatal corticosteroids were used routinely. Also, mostly of the trials were done in university hospitals. More studies must be done to determine if a 48-hour delay in delivery to allow for patient transfer and a course of corticosteroids improves results In the meantime, a short trial of tocolysis for preterm labor is reasonable if corticosteroids or transfer is indicated.

Anotayanonth s et al. Betamimetics for inhibiting preterm labour. Cochrane Database Syst Rev 2004;(4):CD004352

REFERENCES

(1) American corporation of Obstetricians and Gynecologists. ACOG committee opinion no. 295: pain relief during labor. Obstet Gynecol 2004;104:213

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