임신 중 태아의 신장의 신우가 부풀어오르는 증상.
경미한 신우확장증의 경우, 다수에서 요로계 폐색과 관련이 없고 임신 기간 중 또는 출생 후에 자연 소실되는 경향이 있다.
산전 초음파가 널리 이용되어 태아 신우확장증의 발견이 많아짐에 따라, 부모의 불안감이 커질 수 있기 때문에 저절로 좋아지는 신우확장증과 병적인 신우확장증을 조기에 감별하는 것이 중요하다. 임신 중기 신우확장증을 신우의 전후경에 따라 경도 및 중등도 이상으로 분류할 수 있으며 10mm이상을 중증 신우확장증이라 한다.
Fetal pyelectasis can be a relatively common finding in an antenetal ultrasound scan, often detected at the routine 2nd trimester morphology scan. There is a recognised male predilection. The estimated prevalence is at ~ 2% of routine second trimeter scans
Pyelectasis can result from a number of factors. In the majority of cases, it is physiological and resolves spontateously. However, it may also herald the presence or evolution of renal tract pathology, such as :
다운증후군 (Down Syndrome): presence and strength of this association is currently under debate and at best considered very mild. Radiographic assessment
4 - 4.5 mm at 18 - 20 weeks (i.e. the routine 2nd trimester)
5 mm at ~ 20 - 29 weeks
6 mm at 32 weeks
지속적 태아신우확장증의 기준
persistent fetal pyelectasis : > 7 mm in the 3rd trimester
Fetal pyelectasis can also be affected by maternal hydration - physiological fetal pyelectasis
The vast majority of cases (~ 96%) with mild pyelectasis in the second trimester resolve, either during pregnancy or in the early postpartal period. The risk of post-natal renal pathology is increased with :
The presence of fetal pyelectasis is sometimes considered a soft sign for chromosomal abnormalties : see associations above
Antenatally detected renal pelvic dilatation, especially in isolation, is considered a weak predictor of vesicoureteric reflux although postnatal sonographic evaluation is often recommended.
Some advocate a repeat prenatal scan at 30 - 40 weeks gestation for all fetuses with 6 mm or more of renal pelvic dilatation is detected prior to 28 weeks as well as postnatal follow-up for persistent pyelectasis
Post natally, most cases with pyelectasis resolve spontaneously in the first year of life and invasive procedures are not required.