Zika Virus Update: Early Ultrasounds Cannot Detect Microcephaly

Ultrasound failed to detect microcephaly in the early weeks of pregnancy, creating more questions than answers about the Zika virus. On a new study published on March 30, three ultrasounds returned negative in a Finnish woman who was positive for Zika virus.

CNN reports on a new finding discovered in a Finnish woman, who was infected by Zika, but showed no signs of microcephaly in the early ultrasounds done on her. A new study published in the New England Journal of Medicine followed the case of a 33-year-old woman who was infected by the Zika virus after she visited countries positive of the infection. She was 11 weeks pregnant when she travelled to Mexico and Guatemala.

Pregnant Women May Be Able To Get Zika Answers Earlier via MRI and intensive ultrasound #pregnancy #Zika #surrogacy https://t.co/aiBq3qTelU

— Lila Seif Fertility (@LilaMSeifEsq) March 31, 2016

Although the exact location of transmission was not determined, the woman who was not identified remembered being bitten by mosquitoes in Guatemala. She reported feeling ill after returning home to Washington. When she had herself checked by a doctor, tests showed that she was positive with Zika infection. She reported feeling feverish with pains in the muscles and eyes. Later on, she developed a rash.

According to Reuters, ultrasounds showed no signs of microcephaly at week 13, 16, and 17 weeks, not until week 19. At this time, the fetal brain showed signs of not developing properly. During a magnetic resonance imaging (MRI) follow-up exam, the fetal head showed signs of shrinking, from the 47th percentile to the 24th percentile.

Aside from the infant's head circumference, there were also complications in the lungs, liver, spleen and muscles. At this point, the infant's head is not even small enough to be considered as microcephaly. However, given the extent of damage as shown on the MRI results, the woman decided to terminate her pregnancy at 21 weeks.

Previously, infants infected with the virus have shown signs in early ultrasounds. The case of the young Finnish woman clearly shows that Zika may not be detected on a normal ultrasound, and would need an MRI to detect microcephaly early on. Dr. Anthony Fauci, head of the National Institute of Allergy and Infectious Disease, noted of a similar case where development problems have not been detected until 35 weeks into the pregnancy.

The problem now is how to detect early on the extent of damage brought on by the Zika virus. A normal clinic may not be equipped with the necessary tools to detect the virus given that MRI was used to discover the developmental issues. This will be a great challenge especially in countries, where Zika is present. To know more about Zika, check out the video below: