With twins or more, Count the Kicks advises starting daily counts at 26 weeks and counting one baby at a time, each compared only with their own earlier counts. If either baby's movements slow down or change, the rule is the same as with one baby: call now.
When to start
Count the Kicks advises starting to count daily at 26 weeks if you're expecting twins or more, rather than at 28, and notes that this is what ACOG recommends. It adds that there's nothing wrong with starting earlier, to practise and get into a routine.
UK guidance doesn't ask you to count (NHS), but to know your baby's usual pattern of movements. The NHS and RCOG pages on movements that this guide draws on don't give separate advice for twins. When to start counting sets out both views.
One baby at a time
Count the Kicks suggests doing one complete count for one baby, then moving on to the next, rather than trying to follow both babies in the same count. It helps you build up each baby's own usual time.
Its app can count for one baby or two: you choose two, name each baby, and it times how long each one takes to reach 10 movements. How to count your baby's kicks walks through a single count, and a printable chart for each baby works on paper.
Telling them apart
Count the Kicks says it can be tricky to tell which baby is moving. As twins grow into the third trimester, their positions become clearer, and while they keep moving, they may not change position as often as a single baby would.
It also says it's essential to talk with your healthcare provider about any questions you have on counting for your babies. If you're unsure where each baby lies, ask at your next appointment.
Each baby compared with themselves
Every baby has their own pattern of movements, twins included. Count the Kicks advises comparing each twin only with themselves, never with the other twin. A slower count for one baby isn't a result, and a quicker one for the other isn't a pass.
What to look out for is a change in either baby: in how long they take to reach ten, or in how strong their movements feel (Count the Kicks).
If either baby moves less
If either baby is moving less than usual, movements feel weaker, or a pattern has changed, contact your midwife, doctor or maternity unit now. Do not wait until tomorrow, do not wait to finish a count for the other baby, and do not use an app to decide (NHS, Count the Kicks). What to do.
Count the Kicks suggests saying it plainly when you call: that you've noticed a change in your babies' movements and you need to be seen. How many kicks should I feel? covers what the guidance says about numbers.