The following abdominal palpation at 18 weeks of gestation is said to be:
External ballottement - Usually elicited as early as 20th week when the fetus is relatively smaller than the volume of the amniotic fluid. It is difficult to elicit in obese patients and in cases with scanty liquor amnii. It is best elicited in breech presentation with the head at the fundus.
External ballottement
Internal ballottement
Fouh leopold grip
Palmer's sign
Labour - normal, abnormal, malposition, malpresentation and their management