"Low fluid" Oligohydraminos literally means "low fluid, " and corresponds to the amniotic fluid measurement that is performed when a sonogram is done. It may be detected in the second and third trimesters, resulting from many different medical situations and is usually seen in about 10% of pregnancies beyond 41 weeks.
Oligohydramnious. It's fairly common, although, i cannot quote a #. It often constitutes a reason for labor induction.