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Female Reproductive System ORGAN SYSTEMS

Cervical insufficiency

Inability of the cervix to retain fetus, in the absence of uterine contractions/labor (painless cervical dilatation), owing to a functional or structural defect.

Inability of the cervix to retain fetus, in the absence of uterine contractions/labor (painless cervical dilatation), owing to a functional or structural defect.

  • M/C cause of 2nd trimester recurrent pregnancy loss (RPL)

Aetiology

Risk factors:

  • Diagnosis of cervical weakness in a previous pregnancy
  • Previous preterm premature rupture of membranes (PPROM)
  • History of conization (cervical biopsy)
  • In utero diethylstilbestrol (DES) exposure (can cause anatomical defects)
  • Uterine anomalies
  • Multiple gestations
  • Short cervical length (actually been shown to be a marker of preterm birth rather than cervical weakness)

Pathophysiology

Uterine cervix is a dynamic anatomical structure that serves during most of gestation as a barrier between the fetus and its intra-uterine environment and the vagina as the portal to the outside world.

During that time it is a firm structure that predominantly consists of collagen, but in the prelude to parturition the collagen is degraded and the cervix becomes soft and pliable enough to dilate.

Imperfections in the process and/or timing of cervical ripening do occur, given the occurrence of preterm labor and dystocia in labour.

Cervical etiology of spontaneous preterm birth
Cervical remodeling. HPA axis, hypothalamic–pituitary–adrenal axis; PPROM, preterm premature rupture of membranes; PTL, preterm labor; sPTB, spontaneous preterm birth. | Vink, J., & Feltovich, H. (2016). Cervical etiology of spontaneous preterm birth. Seminars in Fetal & Neonatal Medicine, 21(2), 106–112. https://doi.org/10.1016/j.siny.2015.12.009

Infection and inflammation are causally related to preterm labor and cervical ripening. This relates to the cervical properties, as the chance of preterm delivery is inversely related to the length of the cervical canal, which contains mucus with antibacterial properties.

If the mechanical and/or antibacterial properties of the cervix are anatomically or functionally impaired, for example by intra-uterine exposure to diethylstilbestrol, or by surgery/trauma to the cervix, the remaining strength of the cervix may be insufficient to retain the pregnancy.


Clinical features

A history of 2nd/early 3rd-trimester fetal loss, after painless dilatation of the cervix, prolapse/rupture of the membranes, and expulsion of a live fetus despite minimal uterine activity, is characteristic for cervical insufficiency.

  • Pelvic pain
  • Low backache
  • Vaginal spotting

Diagnosis

USG:

  • Shortening and funneling of cervix

Management

Conservative management:

  • Progesterone
  • Bed rest
  • Beta-blockers
  • Antibiotics
  • Anti-inflammatory drugs

Cervical cerclage:

Mainstay treatment
  • Types of cerclage:
    1. Regular transvaginal cerclage at the junction of cervix and fornix
    2. High-transvaginal cerclage after opening the fornix
    3. Transabdominal cerclage at the level of the internal cervical os
  • Types of suturing:
    1. Around the cervix (modified Shirodkar)
    2. With a series of small bites (modified McDonald) (M/C)
    3. With 4 large bites of cervical tissue (4-steps)
1471-2393-7-s1-s17-3
Three types of suturing | Lotgering, F. K. (2007). Clinical aspects of cervical insufficiency. BMC Pregnancy and Childbirth, 7 Suppl 1(Suppl 1), S17–S17. https://doi.org/10.1186/1471-2393-7-S1-S17
  • Contraindications:
    • Severe fetal anomaly
    • Intrauterine infection
    • Active bleeding
    • Active labour
    • Preterm ruptured membranes (PROM)
    • Fetal death

Summary

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