I am confused. We doctors do not think of pregnancy in months, but rather in weeks. If every month were exactly four weeks long, then pregnancy would indeed last 10 months, but that's not how it works on the calendar. Now, obviously you aren't even pregnant yet on the first day of your LMP, but this gives us a good, consistent reference point and is the reference point used all over the world. By using this as the starting point, we calculate your due date to be 40 weeks from that day.
Most miscarriages occur in the first trimester.
At 16 weeks, you are pretty safe. All Rights Reserved. 2000 iVillage Inc. All rights reserved. The information contained above is intended for general reference purposes only. It is not a substitute for professional medical advice or a medical exam.