RENO, NEV. — Sickle cell trait is associated with previously unreported signs of fetal hypoxia, placental infarcts, and possibly excess risk of fetal demise, according to a study presented in poster form at the annual meeting of the Society for Maternal-Fetal Medicine.
“In the past, we have just told these patients, 'Come in every trimester, and we will check your urine [because of increased risk for a urinary tract infection].' Maybe that's not safe,” the study's lead author, Michelle Y. Taylor, M.D., of the department of obstetrics and gynecology at the University of Mississippi Medical Center, Jackson, said in an interview.
In a case review of 131 pregnancies with confirmed sickle cell trait, in which a detailed pathological examination of the placenta was performed, the researchers found that all of the placentas had aggregates of sickled red blood cells in the intervillous space and decidual vessels.
In addition, 92% of the cases had evidence of meconium passage, suggesting hypoxia, and 50% had evidence of an ascending amniotic fluid infection.
There were frank placental infarcts in 16 cases and retroplacental hemorrhage in 11 cases.
There were 10 cases of intrauterine fetal demise (of which 4 were in the cases with infarction), and 1 neonatal death.
Intrauterine growth restriction occurred in 14 cases.
The investigation found a higher-than-expected rate of fetal loss, and no risk factors were noted other than the probability that sickling in the decidual vessels resulted in decreased placental perfusion, Dr. Taylor said in the interview.
All patients in the study were African American, and the group's average age was 24 years.
The average gestational age at delivery was 30 weeks, and all the pregnancies had to be at least 16 weeks to be in the study. A total of 123 pregnancies were singleton gestations, and 8 were twin gestations.
Hypertension was present in 16% of cases.