| Cervical pregnancy | |
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| Vaginal ultrasonography of a cervical pregnancy at a gestational age of five weeks. See image below for details of the visible structures.[1] | |
| Specialty | Obstetrics |
Acervical pregnancy is anectopic pregnancy that has implanted in the uterineendocervix.[2] Such a pregnancy typically aborts within the firsttrimester, however, if it is implanted closer to the uterine cavity – a so-called cervico-isthmic pregnancy – it may continue longer.[3]Placental removal in a cervical pregnancy may result in major hemorrhage.
The diagnosis is made in asymptomatic pregnant women either by inspection seeing a bluish discoloredcervix or, more commonly, byobstetric ultrasonography. A typicalnon-specific symptom isvaginal bleeding during pregnancy. Ultrasound will show the location of thegestational sac in the cervix, while the uterine cavity is "empty". Cervical pregnancy can be confused with amiscarriage when pregnancy tissue is passing through the cervix.
Histologically the diagnosis has been made byRubin's criteria on the surgical specimen: cervical glands are opposite thetrophoblastic tissue, the trophoblastic attachment is below the entrance of the uterine vessels to the uterus or the anterior peritoneal reflection, and fetal elements are absent from the uterine corpus.[4] As many pregnancies today are diagnosed early and no hysterectomy is performed, Rubin's criteria can often not be applied.
True cervical pregnancies tend to abort; if, however, the pregnancy is located higher in the canal and the placenta finds support in the uterine cavity, it can go past the first trimester. With the placenta being implanted abnormally, extensive vaginal bleeding can be expected at time of delivery and placental removal. While early cervical pregnancies may abort spontaneously or can be managed with excision, D&C, suturing, electrocautery, and tamponading,[3][5] by medication such asmethotrexate,[6] and/or byuterine artery embolization,[7] a more advanced pregnancy may require ahysterectomy to control bleeding.[8] The more advanced the pregnancy, the higher the risk for major bleeding necessitating a hysterectomy.[9]
On very rare occasions, a cervical pregnancy results in the birth of a live baby;[10] typically, the pregnancy is in the upper part of the cervical canal and manages to extend into the lower part of the uterine cavity.
A cervical pregnancy can develop together with a normal intrauterine pregnancy; such aheterotopic pregnancy will call for expert management so as not to endanger the intrauterine pregnancy.[11]
The incidence has been reported to be about 1:1,000 to 1:16,000 pregnancies.[8][9][12]
Pregnancies involving the isthmus – the segment of theuterus between the cervix and the fundus – are more common than true cervical pregnancies.[3] While in many situations the cause of the abnormalimplantation remains unclear, there is evidence to link the development of cervical pregnancy to uterine instrumentation, specifically repeated D&Cs (dilatation and curettage).[8][9] Cervical pregnancies are to be distinguished from pregnancies that start from an implantation in a scar of a previouscesarean section, so-calledscar pregnancies.[2]
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