You have to see what affect it has on you, then you'll know for every month after. When my mom did WW she would gain a little about every third or fourth week, but the overall weight kept going down, so she learned not to sweat that little gain.
Best of luck!
And don't drink your water right before you go on the scale, I did that, remember a pints a pound the world around, if you drink a pint of water right before you get on the scale you'll have a pound of water in your belly