[Special management for threatened preterm delivery in multiple pregnancies].

Spontaneous prematurity is more frequent in multiple than singleton pregnancies. It is estimated that 72% of the multiple pregnancies delivered before 33 weeks are spontaneous births, compared with 58% among singletons (NP3). As in singleton pregnancies, uterine contractions, close together, often precede preterm delivery by several days (NP2). The benefits of home tocodynamometry for patients who have already been hospitalized for threatened preterm delivery (TPD) (NP4) is difficult to assess from the data currently available, but it has not been shown to provide any benefits in a population of asymptomatic twin pregnancies (NP1). Cervical ultrasound appears to have good predictive value for preterm delivery when performed for TPD (NP3), although again few data are available. The efficacy of tocolysis appears similar to that for singleton pregnancies (NP3). Although the lack of data prevents us from judging the efficacy of tocolytics such as calcium channel blockers or oxytocin antagonists, it seems logical to use them as first-line drugs, especially because of the increased risk of pulmonary edema in multiple pregnancies with Bmimetics (NP3). Antenatal corticosteroid therapy appears to be less beneficial in multiple than singleton pregnancies (NP3). Pharmacological studies suggest that the dose currently used may be insufficient for multiple pregnancies (NP3). While awaiting results from clinical studies comparing the efficacy of higher doses, we must for now recommend antenatal corticosteroid therapy only at the usual doses. While the rate of in utero transfers to level III facilities is nearly 85% in the case of severe TPD (NP4), this practice must be encouraged still more in view of the benefits of inborn status compared with postnatal transfer. Finally, delayed-interval delivery is a relatively rare obstetrical practice that should be considered on a case-by-case basis when the first fetus is born before 26 weeks. This approach requires tocolysis and antibiotic therapy. The usefulness of cerclage in this situation has yet to be demonstrated. A delayed-interval delivery can prolong the pregnancy by an average of 15 to 30 days (NP4).