Cervical length considered as cut off for preterm labour is?
REF: Manual Of Obstretics 3rd ed by Daftary page 250, Textbook of Basic Nursing by Caroline Bunker Rosdahl, Mary T. Kowalski 9th ed page 906 "At the time of onset of labour the cervix is 1-2 cm in length" The traditional criteria of onset of labour is persistent uterine contraction accompanied by effacement of cervix or dilatation of cervix or both, are reasonably accurate when frequency is 6 or more contractions per hour, cervical dilatation is 3 cm or more, effacement is 80% or more and membrane ruptures or bleeding occurs. EFFACEMENT OF CERVIX: Effacement or taking up is a process by which the cervix is thinned out and gradually pulled up to be incorporated in the lower segment, thereby causing shortening of the cervical length on vaginal examination. The cervix dilates from above downwards, becoming shorter until only the external os remains as a rim. The cervical projection can no longer be felt. The effacement is caused by the contraction and retraction of the upper uterine segment Normally in a primigravida the effacement precedes cervical dilatation, but in most multigravida both occurs at the same time. The cervix is thus significantly effaced before the onset of labour, particularly in nulliparous. Prior to the onset of labour, the cervix is approximately 4 cm long by digital examination. As the cervix shortens with labour, the effacement is described as a percentage of the remaining length. So if the cervix shortens from 4 cm to 3 cm it is 25% effaced, 2 cm is 50% effaced, 100% or completely effaced cervix is paper thin. When the cervix is 100 percent effaced and 10 cm dilated, the first stage of labor is said to be complete
1.0 cm
1.5 cm
2.5 cm
3.5 cm
Cervical Insufficiency