Meconium peritonitis and meconium pseudo-cysts as its special manifestation are assessable by prenatal diagnosis but present in different ways. They can present as fetal ascites or echogenic bowel and cause fetal or neonatal distress, requiring close observation and highly specialised care.

Objectives: Unilateral multicystic kidney dysplasia (MCKD) is the second most common urinary tract abnormality diagnosed antenatally. Whilst an isolated unilateral MCKD has a good prognosis, a poor outcome must be expected when MCKD is associated with other complex abnormalities. Material: Out of 11,176 cases, 693 fetuses were suspected of having urinary tract abnormalities. Urological findings were confirmed in 548 of them. Unilateral cystic kidney was diagnosed prenatally in 85 cases. Results: The study results in a total of 107 cases with proven MCKD. Eighty-five pregnancies with a prenatal diagnosis of MCKD were analysed. The antenatal diagnosis of MCKD was confirmed in 56 cases. Fifty-one children were found to have unilateral MCKD where this had not been explicitly suspected from antenatal scanning. Conclusion: Unilateral MCKD is a malformation with an excellent prognosis for child survival and global renal function if encountered in isolation. However, our analysis of live infants and autopsy cases demonstrates a high proportion of severe associated malformations of the urinary tract and other organ systems.

This study provides evidence that neonatal nephrectomy of unilateral MCDK is rarely required. It also shows that the discussed malformation is not an isolated developmental abnormality. In a high proportion, associated urogenital abnormalities were present and therapeutically relevant, and determined the overall prognosis.