A short cervix diagnosed at 23 weeks can increase the risk of preterm birth. To prevent this, there are several measures that can be taken. One option is cervical cerclage, which involves stitching the cervix closed to provide support and prevent premature dilation. Another option is progesterone supplementation, which has been shown to help reduce the risk of preterm birth in women with a short cervix. Bed rest and avoiding strenuous activities may also be recommended. It's important to consult with your healthcare provider for personalized advice and guidance based on your specific situation. Regular monitoring and follow-up appointments will also be necessary to ensure the best possible outcome for both you and your baby.