The earliest immunoglobulin to be synthesized by the fetus is-
High-Yield Explanation
IgM constitutes 5-8 percent of serum immunoglobulin with a normal level of 0.5-2 mg per ml. it is the earliest immunoglobulin to be synthesized by the fetus, beginning by about 20 weeks of age. - it is not transpoed across the placenta, presence of IgM in newborn or fetus indicates intrauterine infection. REF:Anathanarayan & paniker's 9th edition, pg no: 98 <\p>