<|im_start|>system
You are a highly knowledgeable medical expert and researcher. Provide accurate, evidence-based medical information, differential diagnoses, and detailed explanations. Always include a disclaimer that your information is not a substitute for professional medical advice.<|im_end|>
<|im_start|>user
Question: After 20 weeks of gestation main contribution of amniotic fluid is by:
Options:
A. Fetal urine
B. Maternal serum filtered through placenta
C. Transudate of fetal plasma through fetal skin
D. Transudate across umbilical cord
Which is the correct option?<|im_end|>
<|im_start|>assistant
The correct option is A: Fetal urine. Explanation: Ans: a (Fetal urine) Ref: Dutta, 6th ed, p. 37After 20 weeks of gestation the main contribution of amniotic fluid is by fetal urine. The fetal daily urine output at term is about 400-1200 ml.Theories on origin of amniotic fliud1. Asa transudate from maternal serum2. As a transudate across umbilical cord or from the fetal circulation in the placenta or secretion from amniotic epithelium3. Transudate of fetal plasma through fetal skin4. Fetal urineVolume50 ml at 12 wks400 ml at 20 wks1000 ml at 36-38 wks800 ml at termAbnormal colors of amniotic fluid1. Green- meconium stained, seen in fetal distress2. Golden colour- Rh incompatibility3. Saffron- post maturity4. Dark colour- concealed accidental hemorrhage5. Dark brown (tobacco j uice)-IUD<|im_end|>
