For how many months do you carry a premature baby?

The show: JAG
The episode: "A Separate Peace," Part II, first aired November 28, 2000, now available on DVD. This episode resumes both the main thread of Part I, the investigation into then-Lt. Boone's alleged war crimes in Vietnam, and the subplot of Bud and Harriet dealing with the loss of baby Sarah. (Terry O'Quinn, more familiar from LOST, is present-day Boone, while Darin Cooper plays the Vietnam-era Boone).
What happened: As Bud buries himself in medical textbooks, Harriet goes see Harm for advice. Harriet tells Harm she carried the baby for nine months.
Why it's not quite right: Though the normal gestation for humans is indeed nine months, writer Stephen Zito apparently forgot to consult with Mark Saraceni, writer of "The Princess and the Petty Officer" (two episodes back) regarding all the details of Harriet's labor. In that episode, Bud and Harriet were caught completely by surprise, and Harriet said to the doctor that there were still weeks left, to which the doctor predictably says that the baby is coming out now anyway. So Harriet only carried the baby for eight months. Though this in no way lessens the tragedy of losing a baby, one would think a mother would not get this fact wrong about her own child, even in a conversation as emotional as the one Harriet has with Harm.