DD will be 4 months old in early June. She usually breastfeeds & goes to sleep like a dream but pretty much always wakes me at about 4.30am for another feed. I wondered if I were to give her a bottle of formula around 10.30pm if she'd be more likely to sleep through the night & be satisfied for longer? Is this a good idea or will it constipate and/or upset her? What formula would be good for this if this the way forward? Advice gratefully received!