My DD normally wears a size 4 during the day and for night time I have her in a size 6. I have always gone up about two sizes, it was the only way to make it through without leaks. She sleeps 11.5 hours and some mornings we still have leaks, but definitely not everyday.
Married - July 2010, DD - April 2011, #2 EDD August 10, 2013
Re: Wetting through at night
LCT - 5.15.14 ~ 9lbs, 22.5 inches
Pampers baby dry, never had any leaks. up to 12hr protection