Nerding It Up.

"I'm a week overdue. It is possible that I might never go into labor on my own?"

The magic date is circled in red on the calendar; every day of the 40 weeks that precede it is crossed off with great anticipation. Then, at long last, the big day arrives- and, as in about half of all pregnancies, the baby doesn't. Anticipation dissolves into discouragement The stroller and crib sit empty for yet another day. And then a week. And then, in about 10 percent of all pregnancies, most often those of first-time mothers, two weeks. Will this pregnancy ever end?

Though women who have reached the 42nd week might find it hard to believe, no pregnancy on record went on forever, even before the advent of labor induction. Studies show that about 70 percent of apparent post-term pregnancies aren't post-term at all. They are only believed to be late because of a miscalculation of the time of conception, usually thanks to irregular ovulation or a woman's uncertainty about the exact date of her last period. And in fact, when early ultrasound examination is used to confirm the due date, diagnoses of post-term pregnancy drop dramatically from the long-held estimate of 10 percent to about 2 percent.

Even if you do end up among those 2 percent of women who are truly overdue, your practitioner won't let your pregnancy pass the 42-week mark. In fact, most practitioners won't even let a pregnancy continue that long, choosing instead to induce by the time your baby has clocked in 41 uterine weeks. And, of course, if at any point test results show that the placenta is no longer doing its job well or that the amniotic fluid levels have dipped too low- or if there are any other signs that baby might not be thriving- your practitioner will take action, and depending on the situation, either induce labor or perform a cesarean delivery. Which means that even if you don't end up going into labor on your own, you won't be pregnant forever.

- From, "What to Expect When You're Expecting".