The review found no eligible studies for this question.
The review found no eligible studies for this question.
It is very uncertain whether GM‐CSF‐supplemented culture media changes preterm birth compared with culture media not supplemented with GM‐CSF (very low certainty).
Antibiotics may leads to lower preterm birth < 37 weeks compared with no treatment (low certainty).
It is very uncertain whether progestogen changes preterm birth compared with placebo/no treatment (very low certainty).
The intervention leads to lower preterm birth (before 37 weeks' gestation) (high certainty).
The intervention leads to lower pregnancy with serious adverse outcome (composite including maternal… (high certainty).
Multiple micronutrients showed no clear difference in preterm births compared with control (iron with or without folic acid) (moderate 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).
Vitamin D supplementation showed no clear difference in preterm birth (less than 37 weeks' gestation) compared with placebo or no intervention (low certainty).
A dose of vitamin D 601 IU or higher showed no clear difference in preterm birth compared with 600 IU or lower alone or with other nutrients (low certainty).
A dose of vitamin D 4000 IU/d or more showed no clear difference in preterm birth compared with 3999 IU/d or less alone or with any other nutrient (low certainty).
The intervention may leads to lower preterm birth (low certainty).
Any antihypertensive drug showed no clear difference in preterm birth (< 37 weeks) compared with no antihypertensive drugs/placebo (moderate certainty).
The intervention leads to lower preterm birth < 37 weeks (high certainty).
The intervention leads to lower early preterm birth < 34 weeks (high certainty).
Progesterone showed no clear difference in preterm birth compared with placebo or no treatment (low certainty).
Outcomes for all interventions for smoking cessation in pregnancy showed no clear difference in preterm birth (under 37 weeks) compared with control: subgrouped by main intervention strategy (comparison 20) (high certainty).
Any supplement containing iodine showed no clear difference in preterm birth compared with same supplement without iodine or no treatment/placebo (maternal… (low certainty).