There are some holes in this. Recent films have been giving pregnant women superhuman abilities and strength beyond anything normal. This is the only thing that fails a good tense film. The mother-in-law was over the top and quite surreal, but onto the other characters. The husband and wife couple are very nice people where butter wouldn't melt in their mouths. The villain is just pregnant and evil all because her school crush didn't marry her, but how many decades ago was it since they were last at school???? The police are never called in these films, and when they are the police don't seem bothered.