Later, the sac may be located above the uterine fundus.(56) Thus, interstitial pregnancy detected late appears as an eccentric uterine pregnancy
Ultrasonography remains the main method for the diagnosis of extra uterine pregnancy
(8), however it can be disappointing in advanced pregnancy as occurred in this case.
Barnhart found that more than one-third of such cases were due to a failed uterine pregnancy
, not ectopic pregnancy.
Transperitoneal migration of trophoblastic cells from one extra uterine pregnancy
to the other tube with implantation
 the intrauterine pregnancy masks any underlying [beta]-hCG changes from the extra uterine pregnancy
and vice versa.
The studies also showed similar reproductive outcomes--subsequent uterine pregnancy
and repeat ectopic pregnancy--after salpingostomy by either approach.
Intra uterine pregnancy
in a bicornuate uterus, ectopic pregnancy like tubal pregnancy, Cornual pregnancy and abdominal pregnancies are common sonographic differential diagnosis.
Right salpingectomy was done for right sided ruptured ectopic after confirming position of right pelvic kidney and intra uterine pregnancy
Exclusion of coexistence of intra uterine pregnancy
It appears that ultrascan is a non-invasive technique, relatively more accurate in the confirmation of an early uterine pregnancy
and appears to be safer and simpler procedure which can be repeated without much inconvenience to the patient.
P/A-uterus was 34 weeks with a live intra uterine pregnancy
with transverse lie and the uterus was relaxed.
In contrast, secondary abdominal pregnancy occurs following an extra uterine pregnancy
that ruptures and gets reimplanted within the abdomen with the evidence of tubal or ovarian damage.