Why did a 15-week miscarriage happen after a normal scan?

Question

Hello doctor,

I recently had a miscarriage at 15 weeks. I had my 12-week scan, and everything was normal at that time. The baby was fine, and the pregnancy seemed to be progressing well. Suddenly, at 15 weeks, I developed severe stomach pain that felt like contractions.

I went to the emergency department, and within about 10 minutes, I started bleeding. When I went to the toilet, I passed the baby, who was still attached to the cord.

I was completely shocked by how suddenly everything happened. Before this pregnancy, I also had three miscarriages. My doctor performed blood tests, which were all normal, and a scan of my uterus showed an arcuate uterus. However, I was told that no treatment was needed for it.

Could an arcuate uterus cause a miscarriage at 15 weeks? I am really upset and trying to understand what may have happened.

Please help.

Answer 1

Hello,

Welcome to iCliniq. I am deeply concerned about your worries.

I am very sorry for your loss. What you experienced is sudden and distressing.

I need to clarify a few points:

At what weeks did your previous miscarriages occur?
Did you have pain during those miscarriages, or were they silent losses?
Have you ever had cervical length checked during pregnancy?
Did you have any infection, fever, or abnormal discharge before this episode?
Were you taking progesterone or any pregnancy support treatment?

Based on your history, an arcuate uterus is a mild variation in uterine shape and usually does not cause second-trimester miscarriage. It is generally considered a normal variant and rarely leads to pregnancy loss.

Your history suggests a different possible cause.

Sudden pain followed by rapid expulsion at 15 weeks is more suggestive of cervical insufficiency or a possible acute event, such as infection or preterm labor, rather than the uterine shape itself.

In addition, a history of three previous miscarriages increases the need to evaluate for recurrent pregnancy loss causes such as:

Cervical weakness.
Hormonal support issues.
Autoimmune causes like antiphospholipid syndrome.
Genetic factors.

The possible cause can be recurrent pregnancy loss with likely second-trimester loss, possibly due to cervical insufficiency rather than arcuate uterus.

So my treatment and advice for you are:

In your next pregnancy, early and close monitoring will be very important.
Cervical length scans from 12 to 16 weeks.
Consider cervical cerclage if the cervix is found to be weak.
Progesterone support in early pregnancy.
Screening for antiphospholipid syndrome and thrombophilia if not already done.
Regular follow-up with a high-risk pregnancy specialist.

An arcuate uterus alone is unlikely to be the main cause here.

You still have a good chance of a successful pregnancy with proper monitoring and preventive care in the future.

I hope this information helps. Please feel free to follow up with any further questions.

Thank you.