Abnormalities of placental shape are occasionally seen on ultrasound. They have not been reported to be associated with abnormalities in fetal anatomy and karyotype. Here, we report on a rare case of placenta fenestrata with triploid karyotype. A 15-year-old patient presented at 21 weeks and 3 days gestation for ultrasound evaluation following an abnormal triple screen and abnormal ultrasound. Multiple fetal abnormalities were noted as well as several cystic areas with pulsatile flow on Doppler ultrasound in the placenta. After termination of the pregnancy, a rare abnormality in the placental shape, placenta fenestrata, was noted. The fetal karyotyping showed a triploid karyotype. This is the first reported case of placenta fenestrata diagnosed on ultrasound. In addition, this is also the first reported case of karyotype abnormality associated with abnormality of placental shape.