Your question is very confusing. Do you mean if the baby is harmed by swallowing amniotic fluid, the answer is NO
Mother nature would not have it so that a fetus can get poisoned by his mother's fluids. As a matter of fact babies have been known to swallow, urinate and even poop (watery liquid) in their mother's womb. Its the most natural thing in the world. The only times that a baby has been in danger is when he can not come out at the right time and takes a breath inside his mother's womb driving amniotic fluid with feces into his lungs; proper pumping needs to be done to save the baby's life but that only occurs when birth is delayed.
That's one of the reasons why c-sections have increased so highly in the last 10 years to save babies lives.
To answer your question, no sucking in your stomach will not hurt the baby, as the uterus keeps its shape to protect the baby, but better not to do it.