Vaginal progesterone showed no clear difference in preterm birth less than 28 weeks compared with no treatment or placebo (low certainty).
Intramuscular (IM) progesterone may leads to higher preterm birth less than 34 weeks compared with no treatment or placebo (low certainty).
Intramuscular (IM) progesterone showed no clear difference in preterm birth less than 28 weeks compared with no treatment or placebo (moderate certainty).
Intramuscular (IM) progesterone showed no clear difference in preterm birth less than 37 weeks compared with no treatment or placebo (high certainty).
Vaginal progesterone showed no clear difference in preterm birth less than 34 weeks compared with no treatment or placebo (low certainty).
Acupuncture showed no clear difference in preterm birth less than 37 weeks compared with placebo (low certainty).
Lower genital tract infection screening probably leads to lower preterm birth less than 37 weeks compared with no screening (moderate certainty).
It is very uncertain whether the intervention changes any preterm birth (birth < 37 weeks) (very low certainty).
The intervention showed no clear difference in any preterm birth (birth < 37 weeks) (low certainty).
The intervention showed no clear difference in preterm birth (< 37 weeks' gestation) (high certainty).
Cerclage leads to lower preterm birth before 34 completed weeks compared with no cerclage (high certainty).
Calcium supplementation showed no clear difference in preterm birth (a) Birth prior to 37 weeks compared with placebo or no treatment (maternal outcomes) (moderate certainty).
Calcium supplementation showed no clear difference in preterm birth (b) Birth prior to 34 weeks compared with placebo or no treatment (maternal outcomes) (moderate certainty).
The intervention leads to lower preterm birth (before 37 weeks' gestation) (high certainty).
The intervention leads to lower preterm birth less than 34 weeks' gestation (high certainty).
It is very uncertain whether the intervention changes preterm birth less than 37 weeks' gestation (very low certainty).
It is very uncertain whether SOF Immunological sealant changes preterm birth less than 37 weeks' gestation compared with standard care (very low certainty).
Vitamin D + calcium supplementation may leads to higher preterm birth (less than 37 weeks' gestation) compared with placebo or no intervention (low certainty).
Vitamin D + calcium + other vitamins and minerals showed no clear difference in preterm birth (less than 37 weeks' gestation) compared with calcium + other vitamins and minerals (but no vitamin D) (low certainty).