Transcervical and transabdominal CVS are both carried out before the fetus is fully formed. Apart from an increased risk of miscarriage, the procedures may cause strong uterine cramps, which disrupt blood circulation through the fetus's extremities. This may lead to incomplete development of the fetus's limbs.
子宮沖洗術與絨毛穿刺都在胎兒發育尚未成形時進行，除容易造成流產，手術也會引發子宮強烈收縮，影響血液循環，導致胎兒末梢四肢發育不完全。