How many weeks pregnant am I?
To determine your due date, health professionals count 40 weeks from the first day of your last menstrual period (LMP) rather than trying to guess exactly when the sperm met the egg. (You can use our pregnancy due date calculator to check how many weeks pregnant you are!)
Health professionals use your LMP to date your pregnancy because many women do not know what day they ovulated. Even if you know the day you had sex that resulted in pregnancy, it may not be the day you got pregnant: sperm can stay in the uterus for up to five days waiting for an egg to be released so it can be fertilized.
Advertisement | page continues below
Using your LMP to find your due date means that when you get confirmation that you are pregnant, you will most likely be 4 or 5 weeks along.
How many weeks pregnant?
Gestation is 40 weeks – although you’re just as likely to give birth a few weeks before or after that.
How many weeks are there in a trimester?
Each trimester lasts about 13 weeks. The first trimester lasts until the 13th week of pregnancy, the second trimester lasts from the 14th to the 27th week, and the third trimester starts on the day you are 28 weeks pregnant and lasts until the 40th week (or until you deliver the baby).
How many trimesters are there in pregnancy?
There are three trimesters: the first trimester (early pregnancy), the second trimester (mid-pregnancy), and the third trimester (late pregnancy).
Week to month pregnancy chart
Check out our chart to see how the weeks, months and trimesters of pregnancy stack up against each other.
How many months pregnant am I?
You can use the chart above to figure out how pregnancy weeks correspond to months. Keep in mind that you are not technically pregnant for a month until, for example, 4 weeks have passed. But you are “in your first month” during the first 4 weeks and “in month nine” during the last 4 weeks.
Isn’t the month four weeks long?
In fact, in a typical year, February is the only month that lasts four weeks (or 28 days). All others are either 30 or 31 days. On average, a month is 4.3 weeks, which means that the number of weeks and months of pregnancy do not completely match. And that’s why some months on the list are four weeks long, and some are five weeks long.
Advertisement | page continues below
Is the pregnancy nine or ten months?
Forty weeks is actually just over 9 months. For example, if your last period started on January 1st, your due date would be October 8th. So it’s more like nine months and one week (or even longer if you’re overdue).
So when will I have my baby?
Your provider counts 280 days (40 weeks) from the first day of your LMP to determine your appointment. But keep in mind that this is just an estimate. Only 5% of babies are born on time. You are just as likely to deliver any time during the two weeks before or after that day. Your baby is considered full term between 39 and 41 weeks.
Note: Not everyone ovulates exactly two weeks after LMP, so your due date may be adjusted if an early ultrasound shows your baby is more or less developed than expected.