Heya, I take Elevit with Iodine and they are horribly huge! I have a trick with swallowing though; put the tablet on the back of your tongue, have a sip of water and tip your head forwards, almost upside down to swallow.
People usually tilt their heads backwards when swallowing tablets but that actually makes it harder to swallow because it stretches the esophagus.
It works for me, good luck!
Have you tried PregVits? They are quite small but have to be taken twice a day. Here in Canada you need a prescription for them. But they have been small enough to cope with for me