Large birth weight is a typical complication of gestational diabetes [GDM], a condition which affects around 200,000 pregnancies annually in the US. According to the NIH, physicians generally screen for GDM at around 24-28 weeks, earlier if there are more diabetes risk factors.
Still, for some lady in Texas with GDM, large was supposed to be 12 pounds, not 16.
AP-US-ODD-Big-Texas-Baby.html [ap/nyt]
Gestational diabetes [wikipedia]
