Amniotic Fluid Index: Understanding Your Scan Results & Pregnancy

Question
Dear Dr,
I am 28 years old and am 29 weeks pregnant with my first baby. I had a scan yesterday. My amniotic fluid index was 11 which I was told is exact lower limit for my period of gestaion and is "just adequate". My doctor is not very worried and he says that we will have to repeat a scan at about 32 weeks and then take a call on whether early delivery by C-section will be necesary. At 24 weeks, my AFI was 9.2, which was marginally less. So, I have obviously improved. My baby's weight at this point in time is 1.3 kilos which I am told is also normal. My questions are- what are my chances of having a normal delivery? Will I have to have an early delivery at 35 weeks and if so, will the baby have to be in the NICU? Since the baby's weight is normal, I am told that the reason for low amniotic fluid is not placental insufficiency. Then could it be that the baby's kidneys are deficient? But the anomaly scan showed normal kidneys.I hope everything will be alright. Thank you so much for taking time out to answer my queries.

Answer
Amniotic fluid is constantly produced by the baby. The baby urinates and swallows amniotic fluid all the time. If there is any fluctuation of swallowing, there is more amniotic fluid. If there is any slow excretion by the kidneys, there is less amniotic fluid. We usually do not worry or are pushed to deliver until the AFI droppes to less than 6. Although your AFI appears at the low endof normal at this time, there is no way to predict what it will be at 35-36 weeks gestation. I'm sure that you will have serial sonography and if the AFI drops too low, you will either be induced or deliver by cesarean. Don't worry at this point.