Until the rules change at the end of the year, as mentioned by Purple Viking, companies can still include pregnancy exclusions on their policy. From January you should be able to purchase cover that does not automatically exclude you just because you are pregnant.

In the meantime you have the choice of finding a policy that best suits your needs accepting that there is no cover available in respect of anything related to the pregnancy and then buy a further policy in January. Alternatively you could hold off on purchasing cover until January taking the risk of cancellation and loss of your holiday deposit whilst waiting for the rules to change.

Hope this helps.