Am 156cm husband is 190cm. 20 week scan showed that our baby girl is growing a week ahead and measerments are way above average. what does this mean?

Well,healthy baby: It is a good news that the baby is growing at20 weeks of pregnancy ,as expected baby will keep on growing and will be big baby .Sometimes big babies have transitory breathing or low glucose problems which are easily corrected .

Baby size: Well, estimated fetal weight are just that..estimates. Every baby grows at a different height and weight. Some of that is based on genetics, but alot of it is based on your diet. Women who eat a lot of starchy food (pasta, potatoes, bread, etc) and simple sugars and sweets are more inclined to have bigger babies. Women who are obese also have this risk. But one week ahead is typical. Its ok