Mysterious Type Of Pregnancy
A recent article in TOG: The Obstetrician and Gynecologist, talks about a mysterious type of pregnancy called "pregnancy of unknown location" or PUL. Most pregnancies mark their territory within the uterus, but PUL describes a case where there's a positive pregnancy test, but no sign of pregnancy inside or outside of the uterus during a transvaginal ultrasound or laparoscopy. As many as 31% of women in early pregnancy are found to have a PUL, though an experienced ultrasound technician can bring this figure down to 10%.
Most PULs run a low risk for being deemed ectopic or outside of the uterus. But correct evaluation and detection is of the utmost important. While ectopic (also known as tubal) pregnancies resolve spontaneously 15% of the time, there's no way to know which tubal pregnancy will resolve on its own and which will cause a rupture and endanger a woman's life.
Serum levels of hCG, the pregnancy hormone, can give a helpful clue to the location of the pregnancy. 70% of ectopic pregnancies are accompanied by a rise in hCG that is slower than that of a normal pregnancy, or a drop that is slower than the minimum expected in a spontaneous abortion (miscarriage). Still, up to 15% of healthy pregnancies have a doubling time that falls below or exceeds the norm. That makes the test undependable in confirming a diagnosis of tubal pregnancy.
In the case where transvaginal ultrasound is performed, a finding of ectopic pregnancy is based on the detection of a sac outside of the uterus as well as other signs including a complex adnexal mass which is a lump of tissue in close proximity to the uterus, or echogenic fluid which is fluid detected through ultrasound technology. If all three factors are found, the chance of an ectopic pregnancy is 93.5-100%.
In PUL, there are four possible outcomes: the pregnancy disappears (44-69%), normal intrauterine pregnancy is confirmed (75%), ectopic pregnancy (8.1-42.8%), and persistent PULs (2%) in which hCG levels don't drop, there's no sign of disease, and the location of the pregnancy cannot be determined.
Proper management of PUL has reduced the number of surgical interventions but requires many visits to a prenatal clinic or obstetrician for proper diagnosis. The article advises that doctors treat women presumed to have undergone a complete miscarriage as having PUL's. Pregnancy hormone levels should be monitored until they hit zero in order to prevent the possibility of internal hemorrhage.