Thursday, January 15, 2015

If Gestational Sac is Less than 25mm, This is Not a Blighted Ovum...yet!

I love the UK's new guidelines for diagnosing a blighted ovum.  We've been saying for years that a blighted ovum should not even be suggested before nine weeks and now research is backing that up.

You can read more about my excitement here: 
Misdiagnosed Miscarriage? The UK Has Changed their Guidelines. Your Doctor Needs to Take Note

I am happy to say that a French study confirms not diagnosing a blighted ovum before the gestational sac reaches 25mm.  For women with a tilted uterus, that puts them at about nine weeks. 

French guidelines for diagnostic criteria for nonviable pregnancy early in the first trimester and for management of threatened miscarriage and nonviable pregnancy 

"First trimester nonviable pregnancy is established with gestational sac mean diameter and embryo crown-rump length. Mean sac diameter≥25mm without embryo (LE2) or embryo crown-rump length≥7mm without heartbeat (LE2) by transvaginal sonography allows to diagnose pregnancy failure."

In other words, if your gestational sac is growing, your doctor should not even be suggesting a blighted ovum until the sac is 25mm.  Some guidelines recommend waiting an additional week after you reach 25mm to just be sure.  Of course, this is if there are no serious complications (i.e. ectopic, partial mole, etc...).

Why do I feel so strongly about this?  My gestational sac at 7 weeks 5 days measured 21.5mm and still looked empty.  I turned down the D&C for the second time.  At 8 weeks 5 days, my sac measured 28.5mm and we saw my little one with a very strong heartbeat.    Since I shared my story, many more women have had similar stories. 

Your doctor really should not be diagnosing a blighted ovum if your gestational sac is still less than 25mm and growing.  If he or she is, might be time to find a new doctor.


  1. I had a transabdominal scan today was supposed to be 8 weeks according to LMP 20mm 6 week gestational sac no yolk no fetal pole doing hcg tests hoping for the best

    1. If the sac is growing from week to week and not yet measuring over 25mm, it is still too early. (((hugs)))