QuestionI am already 22 weeks pregnant. Is it more difficult or dangerous to get an amnio the futher along you are?
-------------------------
Followup To
Question -
My triple screen came back as positive for Downs (1:186). I had an ultrasound and everything showed normal except for the head to belly ratio. The normal range for the head was 1.06-1.26 and we measured at 1.27. Is this something that I should be concerned about? I am waiting to get another appointment with radiology for another ultrasound next month. Also, when is the best/safest time during pregnancy to get an amnio done?
Thank you in advance, Stacey
Answer -
Your head to belly ratio appears normal and is not something to be concerned with. However, an alphafetoprotein screen indicating an increased risk for Down's of 1:186 is enough to warrant an amniocentesis. This should be done at 18 weeks gestation so as to give you time to make intelligent decisions about either continuing the pregnancy or terminating the pregnancy if you do have any chromosomal abnormalities.
AnswerYou can have an amniocentesis at any time during the pregnancy. However, if you have an amniocentesis and a karyotype is done to evaluate your chromosomal makeup, and it is found that you definitely have a chromosomal abnormality, such as Down's Syndrome, it may be too late to do anything about it. In most states, it is illegal to terminate a pregnancy after 24 weeks gestation. It usually takes 14 days after an amnio to report the results of the chromosome analysis. If you have passed 24 weeks gestation by then, you cannot terminate the pregnancy. However, just being aware of the situation will help you prepare for the baby, in any case. By doing the amnio at 18 weeks, the results are usually received by 20 weeks and a decision as to whether to continue or terminate the pregnancy can be made.
