A sonomarker found at the 20-week ultrasound

My experience after the 20-week ultrasound.

I was pregnant with our first child when we nervously entered the sonographer’s office. We hadn’t seen our baby for seven weeks, so we were looking forward to spending half an hour watching our little one on screen. But we were also a bit anxious — would everything be “okay”?

The scan went smoothly until the sonographer told us she had found a choroid plexus cyst in our baby’s brain. She immediately explained that this usually doesn’t mean anything — but I didn’t really hear that part. We were both completely shocked. A cyst in our baby’s brain? In the brain?! My mind filled with terrifying images of disabled children or losing our baby altogether. I burst into tears, and Tom started asking dozens of questions.

Seeing our reaction, the sonographer invited us to sit down at her desk. She explained that a choroid plexus cyst is actually quite common in babies — it’s a small, fluid-filled space in the side ventricle of the brain where cerebrospinal fluid is produced. It’s found in about 1 in 50 to 100 pregnancies during an ultrasound. The presence of a single cyst does not indicate any brain disease. In most cases, it disappears on its own during pregnancy or shortly after birth. Even if it remains visible, it has no effect on a child’s development, she reassured us.

The sonographer also warned us not to go home and start Googling (something she was right to assume I’d do the moment we got home). She explained that concern is only justified when a choroid plexus cyst is found together with other abnormalities on the scan — but she had carefully checked our baby and seen nothing else. So this was an innocent finding, nothing to worry about.

We walked out of the clinic in a daze. Not relieved — still shaken. The celebratory apple pie we’d planned to have at the café nearby was quickly skipped; we went straight home. Once there, we went online immediately. Everything we read confirmed what the sonographer had told us, yet my heart couldn’t believe it. There was something in our baby’s brain!

Then the phone rang — to my great relief, it was Pippa, our midwife. The sonographer had called her, guessing (correctly) that we wouldn’t be fully reassured. Pippa patiently answered all our questions, which helped us calm down a bit. Still, over the next few days, I spent hours scrolling through online forums, searching for proof that it really was “nothing.” The thought kept buzzing in our heads for weeks. We started buying baby items, preparing for the birth, but the worry never completely went away.

At 34 weeks, our midwife became concerned about the baby’s growth and referred us for a growth scan. Thankfully, everything looked fine — our baby was growing well. We couldn’t resist asking if they could check whether the choroid plexus cyst was still there. The sonographer looked… and it was gone!

Even though we knew that, medically, it wouldn’t have mattered if it was still there — we were overjoyed and relieved. We left the hospital in tears of happiness. Fourteen weeks after that 20-week ultrasound, we finally had that piece of apple pie at our neighbourhood café.

Looking back, there’s nothing we could have done differently. But I had never realised how a so-called “innocent finding” could cloud your entire pregnancy and cause so much worry for parents.

Mariska, mother of three-month-old James.