Your knee-jerk reaction (and mine) is No! However, an interesting article from Mosiac makes the case that the argument is not clean cut.
Because it has long been considered unethical to include expectant mothers in clinical trials, scientists simply don’t know whether many common medicines are safe for pregnant women. Of the more than 600 prescription drugs that the US Food and Drug Administration approved between 1980 and 2010, 91 per cent have been so meagrely researched that their safety during pregnancy remains uncertain.
The provide the example of thalidomide as a case study for where running clinical trials on pregnant women could have avoided the serious birth defects that occurred in as many as 12,000 children.