Operatively, a distinction is made between prophylactic (= primary) and therapeutic (= secondary) operations. They are performed in the form of cerclage (cervical encircling) or total closure of the cervix. Definition of prophylactic/primary surgery for cervical insufficiency (preferably cerclage/cervical wrap):
- Patients with:
- Congenital disorders:
- Malformations of the Müllerian ducts ( e.g., uterine malformations).
- Deficiency of:
- Elastic fibers
- Collagens
- Traumatization of the cervix by:
- Rupture (birth injuries, Emmet tear).
- Conization (the risk of an insufficient cervix is increased if the diameter of the cone is > 10 mm).
- Overexpansion in:
- Instrumental abortions
- Intrauterine surgeries
- Distressing pregnancy history (risk collective) without evidence of miscarriage or preterm birth with unremarkable cervical length:
- Condition after:
- One or more late abortions
- One or more premature births
- Condition after:
- Congenital disorders:
Definition of therapeutic/secondary surgery for cervical insufficiency (preferably cerclage/cervical wrap):
- Patients with:
- Opened cervical canal (> 1 cm).
- Amniotic sac prolapse (prolapsed amniotic sac).
- Shortened cervix length (< 25 mm).
1st order
- The main surgical procedures are those according to Shirodkar and according to McDonald’s (the different techniques will not be discussed here).
2nd order
- Total cervical closure: this operation is used as an early prophylactic intervention (12-16 weeks of pregnancy) in pregnant women with habitual miscarriage (repeated miscarriage, ie, from the third spontaneous miscarriage, with initially unclear cause), as well as condition after premature birth (the surgical technique will not be discussed here).
The problem of all therapeutic measures (surgery, pessary, progesterone) in the context of cervical insufficiency, concerning both prophylactic and therapeutic indications, is the evidence. Many decisions are made on a gut feeling due to lack of controlled studies. Even the more recent data leave many questions unanswered. At present, the following appears to be relatively certain:
- Therapeutic cerclage (surgical wrapping of the cervix): in singleton pregnancies and condition after late abortion or preterm delivery and cervical length before 24 weeks’ gestation <25 mm, the incidence (frequency of new cases) of preterm delivery can be statistically significantly reduced compared with wait-and-see behavior. However, perinatal morbidity and mortality (incidence of illness/number of fetal deaths in the perinatal period/deaths and deaths up to day 7 postpartum) did not differ. Maternal complications (fluor vaginalis/vaginal discharge, hemorrhage, (febrile) inflammation) and sectiorate rates were higher in the cerclage groups than in the control groups.
- Vaginal progesterone application or a cerclage pessary may be alternatives in the future, as outcomes are not significantly different.
- Emergency cerclage: although the numbers are small, when the cervix is > 3 cm wide compared with bed rest treatment, pregnancy can be significantly prolonged, the incidence (frequency of new cases) of preterm birth below 34 weeks’ gestation and neonatal morbidity (incidence of disease in newborns) can be reduced.
- Prophylactic cerclage: Whether total cervical closure is possibly superior to cerclage in a risk population (condition after preterm birth) cannot be answered at present, because a valid (scientifically valid) statement is not possible due to too small case numbers.