Choi SJ, Kwak DW, Kil K, et al. - The efficacy of two types of progestogen therapy for preventing preterm birth (PTB) was compared via performing a multicentre, randomized, open‐label, equivalence trial and a meta‐analysis. Randomization was performed of 266 eligible women at 16‒22 weeks of gestation to receive either 200 mg of vaginal micronised progesterone daily (vaginal group) or an intramuscular injection of 250 mg 17α‐hydroxyprogesterone caproate weekly (IM group). Of these women, 247 women (119 and 128 women in the vaginal and IM groups, respectively) were available for the intention‐to‐treat analysis. Outcomes suggest that treatment with intramuscular progestin might enhance the risk of PTB before 37 weeks of gestation by as much as 13.8%, or decrease the risk by as much as 7.6%, in women with a history of spontaneous PTB or with short cervical length, when compared with vaginal progesterone.