Calorie deficit and cardio, or maintenance with heavy lifting?

Slasher09

Forgive me if this is asked all the time. Up until 2 years ago my only mental frame of diet/exercise involved not eating or purging, so I will admit I know very very little about lifting and strength training

I am about 155 pounds currently. I would say I am comparable to the way my body was in HS and in college (size 8/10, measurements 28" waist, 41" hips, 24"thigh). I am 5'5-5'6 and although my BMI is about 25 I am not considered by myself or others to be overweight or really over-fat. After college due to my eating disorder I had thinned out over a few years. I was 140-145 but I was a size 6 (26" waist, 38" hips, 22"thighs) so at 10 pounds less I was much much leaner. I have been trying to get into better shape for my wedding/honeymoon and had been trying to eat at a calorie deficit and lose weigh.

Then it hit me while I was trying to figure out what my "end game" is. I really enjoyed that I was leaner back then, but I must have had much more lean muscle mass than I do now. I got pregnant in Nov 2012 and I lost SO MUCH muscle being pregnant and my body composition is much different than it used to be.

I am getting married/going on my honeymoon at the end of march, and then ideally we are trying for another baby this spring/summer. I am starting to think that "dieting" to lose weight just to gain it back pregnant might be fruitless, and perhaps I should focus more on increasing my lean muscle mass and working to preserve it during my next pregnancy. I am very confused by whether you eat at a deficit, maintenance or surplus to put on muscle. I would like to set a good, healthy routine now that I have had going for a few months so that way when I become pregnant again and inevitably want to eat poorly and not exercise it will be more of a routine to help stick to it. (I was incredibly sedentary and lived on chocolate last time)

Would anyone have advice? Or could point me in the right direction to advice? A final question would be...(please forgive me if this is a really stupid question) Yes, I would like to have a decrease in my body fat %. Not a lot, maybe 5% or so....does this have any bearing to how I eat?