The Effect of Garlic Tablet for Preventing Preterm Labor: A Randomized Clinical Trial

Background: One of the important causes of neonatal mortality and morbidity is preterm birth. There is little evidence about the role of garlic in preventing preterm labor. Objectives: This study aimed to investigate the role of garlic tablets in preventing premature birth. Methods: This is a double-blind clinical trial. Five hundred and thirty-seven singleton pregnant women in the 16th to 26th week of pregnancy with a history of threatened preterm delivery (delivery before the 37th week of pregnancy) were included in this study. The participants were randomly divided into intervention (n = 272) and control groups (n = 265). The intervention group received garlic tablets (500 mg/day) every 24 hours for 10 weeks and 250 mg intramuscular progesterone every week until 36 weeks or delivery time. The control group received placebo tablets plus 250 mg intramuscular progesterone (every week until 36 weeks). The primary outcome was the incidence of Preterm delivery (gestational age < 37 weeks). Quantitative variables were expressed as frequency and percentage and compared using the chi-square or Fisher exact test with a small sample size. Numerical data were presented as mean and standard deviation. We used the Kolmogorov-Smirnov test to determine the normality of the data distribution. After that, the relationships of continuous variables with normal distribution were investigated using the Independent T Student test, and continuous variables without normal distribution were investigated with the non-parametric Mann-Whitney test. Multivariate logistic regression analysis estimated different variables' interaction and confounding effects. Results: Four hundred and forty-five had term delivery (82.9%), and 92 (17.1%) had preterm delivery. Seventeen participants in the intervention group (6.3%) and 75 (28.3%) in the control group had preterm delivery (P < 0.001). By considering preterm labor as dependent and other independent variables, the study group (intervention or control) was the only predictor of preterm labor (OR-3.6, CI: 95%: 1.98 - 6.5, P < 0.001). Conclusions: The results showed that the combined treatment of oral garlic tablets and intramuscular progesterone significantly prolonged pregnancy or improved outcomes. Garlic tablets seem to be effective in preventing preterm birth.