How Many Months Pregnant Am I?

A Pregnant couple sitting on the couch talking about doulas
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The average pregnancy lasts forty weeks from the first day of the last normal menstrual period. Most physicians and midwives use the gestation calculation of weeks rather than months because it is more specific.

How Many Months Are There in Pregnancy?

We talk a good game about having nine months of pregnancy. But if you look at it mathematically, there are an average of forty weeks in a normal pregnancy.

If you calculate a month as being four weeks, that makes ten months of pregnancy in every forty weeks. The problem with this calculation is that it has twenty-eight day months, which is not the norm in our calendar months. This is why some people say that there are really ten months of pregnancy. It is also why it is more important for your practitioner to count the number of weeks pregnant you are to be assured that everyone is on the same sheet of music when it comes to how far along you are in pregnancy.

There is also the issue of when you actually are pregnant. Now this honestly doesn't really matter much to most people, since that's just how pregnancy is calculated. And, by the time you have a positive pregnancy test, you are four weeks pregnant. Here are some common breakdowns of the months of pregnancy and their explanations:

Heavy on the First Trimester

  • Month One: Week 1-6
  • Month Two: Week 7-11
  • Month Three: Week 12-16
  • Month Four: Week 17-20
  • Month Five: Week 21-24
  • Month Six: Week 25-28
  • Month Seven: Week 29-32
  • Month Eight: Week 33-36
  • Month Nine: Week 37+

This set of weeks assumes that early pregnancy is very important but that you aren't really pregnant those first two weeks.

Heavy on the Third Trimester

  • Month One: Week 1-4
  • Month Two: Week 5-8
  • Month Three: Week 9-12
  • Month Four: Week 13-16
  • Month Five: Week 17-20
  • Month Six: Week 21-24
  • Month Seven: Week 25-28
  • Month Eight: Week 29-32
  • Month Nine: Week 33+

This set of weeks counts every moment from the last normal menstrual cycle and considers the fact that some women have their babies earlier than forty weeks.

So, as you can see, there are not a lot of solid answers as to the right way to count months of pregnancy. So the next time you are asked: How many months pregnant are you? You will know that you can safely answer, just about any month you feel is appropriate for your gestational age. 

How Your Doctor or Midwife Counts Your Pregnancy

Since your doctor or midwife don't count in months, there is very little ramification for your answer, nor need for justification for the answer. Counting by weeks is what your practitioners will use. This helps them more accurately figure out how far along you are and therefore, what they should be seeing in terms of the health of you and your baby. So the next time you are in for a prenatal visit - be sure to ask for your practitioner's take on the weeks versus months debate.

At one of your first prenatal visits, you can ask for your estimated due date and mark that in your calendar and note the day of the week.

You will also be told how many weeks you are then and can also mark it going forward, changing the weeks on the day of the week that you are due. So, if for example, your due date is on a Monday, every Monday you would gain a week of pregnancy.

What to Do When Someone Asks You How Many Months?

None of this data will keep someone from asking you "How many months is twenty-four weeks?" when you share how many weeks you are with them. But, you can be prepared to explain why the months do not matter and the weeks do. So, whether you answer five months or six months on the chart above, you are still twenty-four weeks pregnant.

This means that you can choose the answer that best suits you. Sometimes you might feel very pregnant and six months makes you feel better than five months. Or, perhaps you are not anxious for the pregnancy to be over and you would prefer to be five months pregnant. This mental game is one that can help you stay sane through a potentially discombobulating time. 

Interested in figuring out when you got pregnant? Try the backwards pregnancy calculator.

Source:

Obstetrics: Normal and Problem Pregnancies. Gabbe, S, Niebyl, J, Simpson, JL. Fifth Edition.

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