The Incompetent Cervix 1

THE INCOMPETENT CERVIX Dr. K. N. Georgewill Department of Obstetrics and Gynaecology, UPTH.

SYNOPSIS –INTRODUCTION –DEFINITION –INCIDENCE –ETIOLOGY / PDF –CLINICAL PRESENTATION

INTRODUCTION The first description of cervical incompetence appeared in the medical literature in 1658 Over 200 yrs passed b/4 it was mentioned again by Grenin in 1865, who speculated that division or dilatation of the cervix might structurally weaken it, making it incapable of supporting a pregnancy to term Only in the past 40 years has the clinical entity of cervical incompetence received significant attention.

Lash and Lash, in 1950, described the technical details of repair of the cervix between pregnancies (wedge excision of the damaged cervix). Shirodkar in 1955, described a method for the management of the incompetent cervix with surgical repair during pregnancy. Shirodkar's contribution, in combination with the modifications described by Barter and colleagues, became widely accepted among American obstetricians. Contributions by McDonald, Mann, Hefner and associates, Page, Barnes, and Baden added significantly to the options in the surgical management of cervical incompetence.

DEFINITION This is the inability of the cervix to support a pregnancy to term due to structural and or functional weakness. It is an important cause of recurrent midtrimester abortions (miscarriages). Recurrent abortion is the occurrence of 3 or more consecutive spontaneous pregnancy losses before the age of fetal viability

INCIDENCE The incidence of recurrent miscarriages in general is difficult to determine but is thought to affect approximately 15-20% of all pregnancies. Once a miscarriage has occurred the risk of further miscarriage rises to about 20% reaching over 40% after three consecutive losses. The incidence of cervical incompetence is also difficult to determine because it is usually over diagnosed but reported incidence in different centres in Nigeria vary between 0.5 - 3.5%. This variation is based on differences in diagnostic criteria and the method of identification of the incompetent cervix.

ETIOLOGY / PDF Functional: no pathology, cause presumed to be the premature triggering of the normal mechanisms for effacement and dilatation of the cervix. Structural defect: congenital or acquired – Congenital: congenital weakness of the internal Os (histologic defect- increased smooth musclce fibres, decreased collagen/elastic fibres = muscular cervix that is inherently weak). female fetal exposure to diethylstilbestrol (DES)MOA unknown. Short, hypoplastic cervix

– Acquired: Trauma to the cervix – overzealous dilatation and curettage – cone biopsy – cervical amputation – difficult or instrumental vaginal delivery (cervical laceration) infection: bacterial vaginosis The most important cause of cervical incompetence is overzealous dilatation and curettage. Three or more first trimester induced abortions by dilatation and curettage carries a 12% risk of a spontaneous pregnancy loss, while a single second trimester induced abortion carries a 14% risk.

RISK FACTOR IN OUR PATIENT Hx of bearing down/pushing against a poorly dilated cervix in her second confinement. CLINICAL PRESENTATION Recurrent, painless, spontaneous midtrimester or early third trimester pregnancy losses, or preterm deliveries. Rupture of the fetal membranes or protrusion of the membranes into the vagina.