Abstract
BACKGROUND Fetal triploidy is a rare, lethal disorder characterized by an extra set of haploid chromosomes resulting in 69 chromosomes (69, XXX; 69, XXY; or 69, XYY). Fetal anomalies and occasionally maternal complications such as hypertension result in a high fetal loss rate during gestation. It is estimated to be present in 1: 250 000 pregnancies at 20 weeks, and very few survive to term. Diagnosis is suspected by antepartum ultrasound and confirmed by invasive testing of fetal cells by karyotype. Management includes pregnancy termination or pregnancy continuation based on the patient's choice. Whether a cesarean delivery should be performed for a nonmaternal indication in a triploid pregnancy is controversial. CASE REPORT A 17-year-old primagravida presented at 33 weeks post-last menstrual period with several weeks of lower abdominal pain and nausea. She had received prenatal care at an outside facility and had a second-trimester ultrasound. She declined amniocentesis for definitive fetal karyotyping. On arrival at our hospital, an ultrasound revealed multiple fetal anatomic anomalies. She developed nonreassuring fetal surveillance and underwent cesarean delivery at 37 weeks. The infant died on day 20 of life. CONCLUSIONS Triploidy is a condition that results in ultrasound-detectable anomalies early in the first half of pregnancy. Noninvasive prenatal screens are unreliable for definitive triploid detection. Confirmation of a fetal chromosomal disorder requires an invasive test such as an amniocentesis. Knowing that the fetus has a lethal disorder allows 2 important options: first, a pregnancy termination; second, declining a cesarean delivery. This case illustrates that refusing the amniocentesis changes the entire course of the pregnancy management.