A short cervix at 21 weeks can increase the risk of premature labor, but with proper management, it can be minimized. Bedrest and progesterone are common interventions to help prevent preterm birth in cases of cervical insufficiency. Bedrest reduces pressure on the cervix, while progesterone helps maintain the uterine lining and prevent contractions. It's important to follow your doctor's advice and attend regular check-ups to monitor your cervical length. In some cases, a cerclage (a stitch placed around the cervix) may be recommended to provide additional support. Remember to stay hydrated, avoid heavy lifting or strenuous activities, and report any signs of preterm labor such as regular contractions or vaginal bleeding immediately to your healthcare provider.