Objectives. Prenatal ultrasonographic investigations have led to an in
creasing number of prenatally detected abnormalities, of which a large
number involves the urogenital tract. This study was performed to eva
luate if endoscopic intra-amniotic access is possible in primates. Met
hods. In 10 midtrimester rhesus monkeys (Macaca mulatta), endoscopic i
ntrauterine fetoscopy was performed with three access cannulas. Using
a Seldinger technique, a vascular access system, and a pediatric lapar
oscopy set, intra-amniotic inspection was attempted. Fetal growth thro
ughout pregnancy was monitored by ultrasonographic measurements of fet
al biometry. Results. Intrauterine access could successfully be achiev
ed in 10 rhesus monkeys with three cannulas. After partial amniotic fl
uid exchange, adequate fetoscopy was always possible. Two monkeys abor
ted on the second and sixth postoperative days. Serial ultrasonographi
c investigations for fetal biometry showed no disturbance of the intra
uterine growth patterns in the remaining 8 monkeys. Conclusions. We cu
rrently conclude that the rhesus monkey model for experimental intraut
erine endoscopic surgery may be suitable for study of the developmenta
l abnormalities of the genitourinary tract.