|Introduction||Embryoscopy and Fetoscopy||Applications||Future Directions||References|
Early pregnancy screening and diagnosis of the fetus utilize techniques such as ultrasonography, percutaneous umbilical blood sampling, high resolution transvaginal ultrasound and chorionic villus sampling. While these methods can be used for diagnosis of many chromosomal and genetic fetal diseases as well as anatomic evaluation of the developmental stages of the fetus, none of these methods involve direct visualization or allow therapy once diagnosis is confirmed. Embryoscopy and fetoscopy, on the other hand, allow for in utero therapy of recurrent genetic syndromes, especially those with recognizable external fetal abnormalities, early pregnancy intervention, as well as real-time observation of limb and body movements, breathing, bladder activity, heart motion, swallowing, and gastric filling .
In 1954, Bjorn Westin performed one of the first direct fetal visualization and prenatal diagnosis of fetal anomalies procedures. In particular, this pioneer performed a hysteroscopic transuterine visualization of 3 fetuses with a 10-mm McCarthy panendoscope. While image quality was rather poor, fetal parts and movements were identifiable . In early 1970s, Valenti and Scrimgeour performed first endoscopic examinations of fetuses using a laparotomy and myometrium incision. Fetoscopy came about in the 1980s when the scope was used transabdominally together with real-time ultrasound guidance, thus allowing close examination of the fetus in utero, sampling of fetal blood, skin and other tissues. However, with its high fetal loss rates ranging from 4% to 8%, inconsistent fetal blood samples contaminated with amniotic fluid , and introduction of ultrasound for prenatal diagnosis of fetal abnormalities using ultrasonically guided needle for fetal blood sampling, made fetoscopy obsolete. Only when fiber-optic technology allowed minituarization of endoscopic equipment such as fiberscopes for use during the 1st trimester, was fetoscopy reconsidered again. Early attempts were done transcervically with a rigid fiber optic endoscope.