Objective: To assess the efficacy and safety of alternative magnesium sulfate regimens used as single tocolytic therapy for preventing preterm labor in patients with symptomatic placenta previa and subsequent changes in cervical length.
Methods: The study was a randomized clinical trial conducted from December 2020 to August 2022 at Assiut Women's Health Hospital, Egypt, including pregnant women from 28 to 37 weeks of gestation with a singleton fetus in PTL and symptomatic placenta previa. The eligible women were randomized to either (group 1 or 2). The primary outcome was evaluating the efficacy of two different regimens of magnesium sulfate in postponing delivery in patients with P.P. in PTL for 48 hours and changes in cervical length.
Results: Clinical and pregnancy prolongation data showed no significant difference between the two therapy regimens. The high-dose group had a considerably longer cervical length (cm) at 48 hours (p<0.001). The low-dose group had a lower 4-hour magnesium serum level (3.98±0.60 vs. 4.80±0.91; p<0.001). Furthermore, when comparing subgroups based on obesity, our analysis revealed a significant increase in non-obese women delivering after 48 hours in high and low groups. Cervical length after 48 hours (cm) was also increased in the non-obese high-dose group (p<0.030). Non-obese pregnancies treated with high-maintenance tocolysis achieve a therapeutic level of magnesium than obese patients(36.1% vs.6.9%, p=0.007).
Conclusions: A high magnesium sulfate regimen in symptomatic preterm P,P in non-obese women may be related to potential clinical prolongation of pregnancy, an increase in cervical length, and achieving therapeutic magnesium levels.