Let me put it this way............ you have seen the typical catholic school uniform? The boys are well covered up, but the girls are in skirts and shirts that usually don't button up to the neck, only just above the bosom. The catholic school uniform for a girl is very, very sexy. There is a reason for that. Any religion based on the bible is male dominated. And anything that is male dominated will put women in submissive and sexual roles. We are to serve and service men. The dresses and skirts are considered modest because they are attractive to men. Jeans can be attractive too, but just a plain pair that are not even tight, with baggy shirts will not turn men on as much. so of course they will complain that you are not dressing "modestly". Also, in pants you are more able to do things that men can do, which makes you in competition for power.
Again.............. submission and sexuality is the key.
Unless you gain a crazy amount of weight you will only need one size of maternity clothing, typically whatever size you are in regular you would be in maternity (accept jeans or clothing that runs small). Start with a bella band (do not buy the knock off at motherhood...it is truly not as good as the original). You can order this at www.bumpfashion.com and get free shipping. This extends the use of your none maternity clothing as well as holds clothing up that drops (typical of Old navy and motherhood items).