Toddler drinking a lot before/during night, too much for one diaper

Question

Our toddler is about 16 months old now, but the situation I’ll describe hasn’t changed much throughout the past half year.

He won’t go to sleep at night (around 19:00) without having had his bottle of (watered down dairy) milk – or bottles: Usually he’s satisfied with 250–300 ml, but sometimes it’s up to triple that. He still wakes up most nights and much of the time a sip of water (not milk like this kid) will put him right back to sleep. He’s not been needing a pacifier for 3 months now (which actually improved his sleeping because he can’t lose it anymore).

Sometimes, usually after 04:00 (or before his noon nap), he won’t stop crying before getting another bottle of milk, often he’ll be hand-signing “milk”, “drink” and “please” if not yet too agitated; afterwards he literally sleeps like a baby another 3 to 4 hours. Even without this early-morning drink, even the best diapers won’t last a complete night. We change him before putting on his pyjamas, check at least once before our bedtime (between 22:00 and 24:00) and whenever he or his sibling wakes us at night, but still it’ll leak more nights than not. Luckily, he’ll often sleep through diaper changing. So we mostly tried what has been suggested for this younger child and was applicable.

Unlike this toddler he’s eating enough throughout the day (whether at home or daycare) and he’s got a belly like a beer-feasting tourist in Mallorca. At average height, he’s always been in the top percentiles weight-wise, almost 13 kg now. He also drinks enough at daytime. His total daily fluid intake is never less than a liter, but maybe not quite as much as this child.

What can we do to have him sleep through the night non-thirsty and without diaper leakage? (Just letting him cry until exhaustion won’t work with neither his mother nor his sibling sleeping in the same room.)

In case anyone thinks it’s relevant: He had been breastfed until about month 7 (unlike this baby) and we stopped giving him formula around his first birthday. He accepted basically any mix ratio of formula, milk and water if it was the right temperature, now even accepts it straight from the fridge. Unlike his older sibling, he never was a fan of any kind of porridge or blended food. Until he actively learned that it can get him what he wants, he wasn’t much of a crier.

Answer 1

As a first step, don't water down his milk at bed time. That's just giving him extra fluids without nutritional value that won't do much to make him feel full. With straight milk, he will probably consume a bit more calories, but not so much fluid, giving him less need to pee.

It may also be a good idea to set a fixed amount you feed him every night. No guzzling down three bottles, just the one he's given. This can also help standardize his bedtime routine, which ought to be helpful in other ways. If he wants more, comfort him but tell him firmly that he's had enough.

Answer 2

He’s not been needing a pacifier for 3 months now

It turned out, this was the solution to, although not necessarily the cause of the problem. After we had given him back a pacifier when in bed, his nightly drinking needs were greatly reduced. It simply may have been the desire for suckling that was satisfied by drinking from a bottle.

He is 3 now and does neither use nor demand a pacifier anymore, but during the months he had it, he grew quite fond of it. We had a much harder time convincing him to give the binkies up for good than it had been with his older sibling. He does not actively remember he already had been without pacifiers for several months once before.