Braxton Hicks contractions occur in most normal pregnancies and are felt as painless and infrequent tightening of the uterus. These contractions usually don’t occur more than once per hour and do not make any changes to the cervix. They are also called as ‘practice contractions’ and are felt by the mother after 28 weeks of pregnancy.
Braxton Hicks contractions do not make any changes to the cervix. Preterm labour is most often felt as a vague, painless tightening of the abdomen, and may or may not be accompanied by one or more signs and symptoms of preterm labour. Preterm labour contractions usually occur in a regular pattern and may cause changes to occur in the cervix. These changes can be detected by atransvaginal ultrasound scan of the cervix at its initial stage, but also by digital examination (per vaginal check) by your doctor.