Ay, hindi ko sure kung 216g ang expected weight sa 18 weeks exactly, I think baby should be around 150-200g pa lang doon, pero basta nasa normal range siya for your gestational age, okay na! Best to ask your OB about this one para sigurado, kasi ang dating ng measurements and baby growth ay different for each pregnancy, at sila lang ang makakasiguro na lahat ay okay with your baby. Congrats sa pregnancy, mommy!