In normal pregnancy, the cervix remain closed and retains the product of conception with in uterus. In normal pregnancy, the cervix remain closed and retains the product of conception with in uterus.

During third trimester During third trimester cervix soften and dilatation occur in response to uterine contractions. if cervical incompetence is present, cervix open prematurely with minimal or absent uterine contractions and pregnancy is expelled.

if cervical weakness is present, cervix open prematurely with minimal or absent uterine contractions and pregnancy is expelled. if cervical weakness is present, cervix open prematurely with minimal or absent uterine contractions and pregnancy is expelled.

Incidence: Incidence: 1-2% of all pregnancy.

Causes : Causes : Congenital causes due to histological defect. Forceful dilatation of cervix (>10mm). Obstetric injuries.(injury to cervix during vaginal delivery).

Causes : Causes : Cervical amputation. Cone biobsy. DES exposure in utero. uterine malformation. cervical cauterization.

During pregnancy: History is characteristic of second trimester abortion with a clinical picture of sudden unexpected rupture of membranes followed by painless expulsion of product of conception.

Examination: Visualization of membrane bulging through the partly open cervix

Investigations: Ultrasound Cervical weakness when internal os dilatation of more than 2 cm and/or shortening by more than 50%.

Diagnosis in non pregnant state:

Previous history of mid trimester abortion (as above). 8mm dilator can pass through internal os easily. Hysterosalpingography. Foley catheter passed in uterus and filled with 1 ml of fluid (6mm diameter) easily slips through cervix.

Treatment during pregnancy

When cervical weakness is suspected (history and finding), cervical cerclage can be considered in subsequent pregnancies to prevent dilatation of internal os. Cerclage is procedure where placement of encircling suture around os using non absorbable suture.

Positive Fetal heart Absence of congenital abnormalities should be documented before operation.

Time of cervical cerclage after 10 th weeks till 24 th weeks under general anaesthesia.

Methods: 1. vaginal operation:

A. Mc Donald's suture (purse string suture) Simple and less complicated.

B.Shirodkar's suture. Need dissection of bladder

Transabdominal cerclage Through laprotomy and it is permanent and delivery should be by caesarean section.

Transabdominal cerclage It done in: Repeated failure of vaginal cerclage. Cervix too short. Cervical amputation.

Emergency cerclage: When cervix dilated 4 cm and membrane bulging but no sign of labour.

Removal of usual types of cerclage 38 weeks of gestation. Expulsive uterine contractions at any gestational age. After rupture membrane at any gestational age immediately.

The success rate is 70-80%.

Contraindications Vaginal bleeding. Infection. Uterine contractions. Dead fetus. Severe congenital abnormalities)not compatible with life).

Cervical cerclage is associated with potential hazards related to the surgery and the risk of stimulating uterine contractions and hence should only be considered in women who are likely to benefit. Complications

Rupture membrane. Infection. Uterine contraction. Cervical dystocia. Cervical tear. if not removed. Displacement of suture.