Thankfully the goodwill towards its affable stars goes some way towards dulling its coarseness — the film is passively racist in its depiction of a dangerous South America, coming more from Levine's hammering of cliche than actual ill intent.
The decrease in dilation is surely the OB's illintent and fear implantation on the woman and not her misjudging the actual dilation to begin with — simply nothing she does is wrong or flawed.