We've had a number of viable pregnancies misdiagnosed as ectopic on the Misdiagnosed Miscarriage site, and, for that reason, I do think it is important that women know that these pregnancies may be misdiagnosed as well.
I wrote a page on this topic: Is This Really An Ectopic Pregnancy (worth a look if you are going through this scare).
Most important thing to note, ABC News reported that up to 40% of ectopic pregnancies are actually intrauterine and not ectopic at all. Wow, 40%, that number still amazes me.
While doing a bit more reading, I came across this medical study:
Am J Obstet Gynecol. 2011 Dec;205(6):533.e1-3. doi: 10.1016/j.ajog.2011.07.002. Epub 2011 Jul 20.
Outcome following high-dose methotrexate in pregnancies misdiagnosed as ectopic.Nurmohamed L1, Moretti ME, Schechter T, Einarson A, Johnson D, Lavigne SV, Erebara A, Koren G, Finkelstein Y.
OBJECTIVE:The objective of this study was to report the outcomes of intrauterine pregnancies misdiagnosed as ectopic and exposed to methotrexate, a major teratogen.
STUDY DESIGN:We report the outcomes of all subjects who sought consultation after exposure to high-dose methotrexate to induce abortion in presumed ectopic pregnancies, which were later identified as viable intrauterine pregnancies by 3 North American Teratology Information Services between 2002 and 2010.
RESULTS:Eight women with normal, desired pregnancies were administered high-dose methotrexate in the first trimester because of presumed, misdiagnosed ectopic pregnancies. All pregnancies resulted in catastrophic outcomes. Two pregnancies resulted in severely malformed newborns with methotrexate embryopathy; 3 women miscarried shortly after exposure, and in 3 the erroneous diagnosis led the physicians to advise and perform surgical termination.
CONCLUSION:Erroneous diagnosis of intrauterine pregnancies as ectopic with subsequent first-trimester exposure to methotrexate may result in the birth of severely malformed babies or fetal demise.
What to take away from this study: Doctors are recognizing that they are, on occasion, misdiagnosing viable pregnancies as ectopic. Mothers need to recognize this as well. If they see the sac outside the uterus, your doctor knows what to do. If no gestational sac is visible anywhere, talk to them. Get a second opinion if needed but make sure you waste no time. We have had women tell us they've taken the medication and later found out they still had a viable pregnancy. But, serious complications may arise if you take this medication with a viable pregnancy.
As always (((hugs))) if you are going through this scare.