avent bottles keep blocking up

[bodweena]

hi, i have purchased the avent anti colic bottles for my 7 week old daughter. She is on the 1 month teats but they continually get blocked and she can't get the milk out. I am using aptimel anti colic formula which is new. I make the bottles up with warm water and shake them with the lid on not the teat. I also ensure the lid is not on too tightly. However, it continues to block, often several times throughout the feed. does anyone have a similar problem? any ideas on why? am I doing something wrong or is it just that this formula doesn't work in this bottle?
Thanks in advance

 

[cookiemo]

Is the formula quite thick? Maybe try using the next teat size?

 

[MissFox]

I would try the next size up if the formula is thick. Also maybe try premaking the bottles so the formula is sure to dissolve? IDK. Good luck. I love my Avent bottles.

 

[Supermaiden]

If the formula is thicker than usual stuff, there are always the thicker liquids teats, it may help.