Related Experiment Video
Updated: May 2, 2026

Is My Mouse Pregnant? High-Frequency Ultrasound Assessment
Published on: March 18, 2021
Pregnancy of unknown location
Gökhan Boyraz1, Gürkan Bozdağ1
1Department of Obstetrics and Gynecology, Hacettepe University Faculty of Medicine, Ankara, Turkey.
Pregnancy of unknown location (PUL) is defined as the situation when the pregnancy test is positive but there are no signs of intrauterine pregnancy or an extrauterine pregnancy via transvaginal ultra-sonography. It is not always possible to determine the location of the pregnancy in cases of PUL. The reported rate of PUL among women attending early pregnancy units varies between 5 and 42% in the literature and the frequency of PUL incidents has increased with the increase in the number of early pregnancy units. The management of PUL seems to be highly crucial in obstetrics clinics. Therefore, in the current review, issues identified from the literature related to pregnancy of unknown location, potential tools for prediction and algorithms will be discussed.
Pregnancy of unknown location (PUL) is defined as the situation when the pregnancy test is positive but there are no signs of intrauterine pregnancy or an extrauterine pregnancy via transvaginal ultra-sonography. It is not always possible to determine the location of the pregnancy in cases of PUL. The reported rate of PUL among women attending early pregnancy units varies between 5 and 42% in the literature and the frequency of PUL incidents has increased with the increase in the number of early pregnancy units. The management of PUL seems to be highly crucial in obstetrics clinics. Therefore, in the current review, issues identified from the literature related to pregnancy of unknown location, potential tools for prediction and algorithms will be discussed.
Related Concept Videos
Ovarian Cycle
Transcytosis of IgG
IgG molecules from a mother undergo transcytosis starting around 13 weeks of gestation. The amount of IgG transferred and entering the fetal blood circulation increases with...
Teratogenicity
Oogenesis
Development of the Oral Microbiota
Uterus and Cervix
The uterus is securely anchored within the pelvic cavity by paired broad ligaments on either side. It is further stabilized by three pairs...

