There is only limited information on its safety in pregnancy, although the little that has been published is reassuring. There are a very limited number of studies that indicate the effectiveness of metoclopramide in the treatment of nausea and vomiting in pregnancy. Side effects include drowsiness, restlessness and occasionally extra pyramidal effects (such as tremor, slurred speech, anxiety, distress and others). This is a prescription only medication.
It is used more commonly in America where the brand name is Reglan; the Food and Drug Administration (FDA) in America has recently recommended that it can be used for up to 12 weeks, but after this side effects can become more severe. There is further information about it at HelpHer.org
UPDATE March 2015:
Recent European recommendations are that maxolon/metoclopramide should only be given for 5 days. This is because it is felt that longer courses are more likely to produce side effects in the person taking this therapy. Specifically, there is concern that beyond 5 days there is more chance of oculogyric crisis and dystonia developing, which put into more understandable terms is facial and skeletal muscle spasms and dizziness.
Please note, there is no new concern about foetal problems this recommendation refers only to side effects for the mother.