Hi Lyn
Generally, waking at erratic times throughout the night is due to hunger,
however, at around 16 weeks babies go through a major development point and these almost always affect sleeping and feeding patterns. Have you noticed a change in her behaviour lately? Perhaps seeming more unsettled, crying easier, grumpier, other sleep disturbances...not napping as well, or taking longer to get to sleep?
If you have, then it's possible that the change you introduced has just coincided with a development point and I'm afraid that you would need to simply ride it out and once it gets better (anything from a few days to a few weeks), try again.
My DD was a nightmare sleeper, taking short naps, always grumpy, taking hours to go to sleep at night, waking randomly (sometimes every hour!), going on nursing strike etc, for around 8 weeks between 4 and 6 months of age. Then one day she woke with a huge smile on her face, was able to play on her own for an hour or so, started to verbalise and finally got the hang of daytime naps. It truly was like the sun coming out after a long storm!
If it's not a development point, I would be likely to think she is hungry and that is why she wakes erratically, rather than at the same time every night.
You don't mention when your baby went to bed before you introduced the change...?
Babies her age tend to sleep for around 14-15 hours in total out of every 24, with about 10-11 of these at night. Ideally, putting her down to sleep at 7-8pm, you would expect her to sleep until 5-6am the following day. Most babies will wake at this time, whether or not they are hungry, but many will be very easy to resettle and then sleep until 7am ish. Putting her down later won't make her sleep longer, because her body clock tells her to wake at 5-6 regardless.
Have you tried simply resettling her when she wakes to see if you can get that extra hour out of her?
Re: the dream feed. If your baby hasn't been having one and was sleeping through, then don't introduce one now. If it's not a development point and she's waking erratically, then consider upping her feeds during the day. You don't mention how often you currently feed...?
Between 4 & 6 months, babies will happily have anywhere between 4-6oz (120-180mls) per feed, 4-6 times per day. You say that your DD is having 6-7oz per feed, but dribbles out the last ounce and is later sick. The dribbling is often a sign that your baby is getting too much milk too quickly and simply can't keep up. The vomiting later could be a sign of overfeeding as her little tummy can only handle so much and the rest has to come out!
No matter how slow-flow the teat is, the milk still comes faster than your baby can cope with and allowing it to dribble out is her only option. I would wonder if looking at your feeding position might help? If you are reclining her to feed and tipping the bottle up, sit her almost upright instead and hold the bottle horizontal, so that the teat is only half full. Your DD will have to work for her milk and will be better able to control her intake.
If you then see that she is consistently leaving behind a couple of ounces, reduce the amount you offer at each feed, but make sure you always offer an ounce (30mls) more than you think she will take for those occasions when she is hungrier than normal.
I hope that this rather long winded reply helps you some!
