Ultrasound-guided ablation of cervical and cornual ectopic pregnancies

Abstract

Cervical and cornual ectopic pregnancies are rare in pregnancies conceived naturally, but occur with greater frequency in pregnancies achieved via in vitro fertilization and other assisted reproductive techniques. Ultrasound permits diagnosis of these ectopic pregnancies early in gestation, which has led to minimally invasive, uterus-sparing, therapy. It is important to distinguish a cervical ectopic pregnancy from a spontaneous abortion-in-progress, which typically appears as an irregularly shaped sac in the cervix or lower uterine segment surrounded by a poor decidual reaction. Similarly, a cornual ectopic pregnancy must be distinguished from an eccentrically positioned intrauterine pregnancy (e.g., a pregnancy in one horn of a bicornuate uterus); the latter has normal-appearing myometrium surrounding the entire gestational sac, while the former has little or no myometrium surrounding the superolateral aspect of the sac. When the diagnosis of cervical or cornual ectopic pregnancy is established, ablation of the ectopic can be performed by guiding a needle into the gestational sac. For cervical ectopics, this is done using a transvaginal transducer with a needle guide, while for cornual ectopics it is done either transvaginally or transabdominally. If there is an embryo with a heartbeat, the needle is advanced into the embryo, and potassium chloride is injected until cardiac activity ceases. In the absence of an embryo or heartbeat, potassium chloride is instilled directly into the gestational sac. After injection, the sac progressively decreases in size, and the cervix or cornu returns to normal over the next few weeks.