Pregnancy With Anomaly Twin Scan
A twin anomaly scan, or mid-pregnancy anatomy scan, is a comprehensive diagnostic ultrasound performed between weeks 18 and 22 of pregnancy. The primary objective is to evaluate the structural development, organs, and overall growth of both fetuses to detect congenital conditions.
Because monitoring two babies introduces unique complexities, this scan takes significantly longer than a singleton exam. The sonographer methodically examines each fetus individually, often labeling them as "Twin A" and "Twin B." The assessment covers critical anatomical structures, including the brain, heart, spine, kidneys, limbs, and facial profiles, to ensure appropriate development.
A crucial component of a twin scan is evaluating the placenta, amniotic fluid levels, and chorionicity—determining whether the twins share a placenta (monochorionic) or have separate ones (dichorionic). Twins sharing a placenta require much closer scrutiny due to higher risks of complications, such as Twin-to-Twin Transfusion Syndrome (TTTS), where blood flows unequally between the babies. The technician will also check umbilical cord insertions and measure cervical length to monitor for signs of preterm labor, which is more common in multiple pregnancies.
While finding a potential structural variation or growth discrepancy can be stressful, identifying an anomaly early gives healthcare providers crucial data. This allows medical teams to build a tailored management strategy, schedule advanced fetal echocardiograms, or plan specialized neonatal care immediately following delivery.
