NT scan 2.7 mm

Hii experienced mommies! Saya first time mum, baru buat NT (Nuchal translucency) scan. Ada tiga measurements doctor dapat for my babys nuchal fold, 2.3, 2.5 mm and 2.7 mm so the average would be around 2.5 mm tapi 2.7 mm maximum. Ramai doctors kata if 3 mm pun masih okay tapi sonographer tadi cakap 2.5 ke atas pun patut dirisaukan dah and i should take follow up actions and jumpa pakar. Based on experience and opinions from other mums, okay tak? Patut di risaukan ke? thank you semua