Objective: Our purpose was to examine the feasibility of diagnosing the Meckel-Gruber syndrome at 11 to 14 weeks' gestation, both in high-risk pregnancies and during routine ultrasonographic screening for fetal chromosomal abnormalities.
Study design: The high-risk population consisted of 9 pregnancies in 7 women with previous pregnancies affected by the Meckel-Gruber syndrome. At 11 to 14 weeks' gestation, systematic ultrasonographic examinations of the fetal skull, brain, kidneys, bladder, hands, and feet were undertaken in each case. The low-risk population consisted of 21,477 self-referred pregnancies undergoing first-trimester ultrasonographic screening for chromosomal defects at 11 to 14 weeks' gestation.
Results: The triad of fetal occipital encephalocele, bilateral polycystic kidneys, and postaxial polydactyly was detected by transabdominal ultrasonography and confirmed by transvaginal scanning in 4 of the 9 pregnancies in the high-risk group. The parents were counseled of the likely recurrence of the Meckel-Gruber syndrome, and all elected to terminate the pregnancy by transcervical evacuation at 12 to 13 weeks. In the low-risk population the only case of Meckel-Gruber syndrome was identified at 13 weeks; in the remaining screened pregnancies there were no other cases of termination of pregnancy or neonatal death with the diagnosis of Meckel-Gruber syndrome.
Conclusion: This report demonstrates that the Meckel-Gruber syndrome can be confidently detected at the 11- to 14-week scan in both high- and low-risk populations.