I know I conceived 10 weeks ago but my first day of my last period was 13 weeks ago how many weeks pregnant?

Your baby is 13 weeks AOG. (age of gestation) So theoretically you have 27 weeks to go ie. (40 weeks AOG). A TERM pregnancy is between 37 weeks AOG and 41 weeks 6 days AOG. That's why your LMP (last menstrual period) is a very important date because this will determine the type of tests you need at certain AOGs and it can also influence the type of delivery for your baby. Obviously, complications would arise if your baby is pre-term and to avoid post-term inductions may be needed, again heightening the importance of knowing your LMP.

The LMP, which is calculated based on the FIRST day of a woman's last period is used to calculate the AOG (age of gestation) of babies for expecting mothers.

This is also used to calculate the EDD (expected date of delivery), you can use Naegele's Rule which is :

EDD = LMP + 9 months + 7 days.

eg. If your LMP is July 27, 2009.

NB. the trick to end of month days is to add the 7 days first so you don't get the month wrong.

Step 1: so July 27 + 7 days = August 3.

Step 2: now add the 9 months to August 3.

therefore your EDD = May 3, 2010.

In some ob-gynae books you can use:

LMP + 9 months + 10 days

You should really get an ultrasound at 6 weeks AOG ,because the calculation of your baby's AOG is more accurate. The earlier you get it, the more accurate it would be.

Congratulations by the way!

P.S. Another measure of AOG is the usage of fundic height. That is, one end of the measuring tape is placed on the pubic symphysis (its the bony part you feel in your pubis) until you reach the fundic height ( where your pregnancy bump ends). The fundic height at 20 and 31 weeks closely correlates with gestational age in weeks. Eg. if the height is 30 cm then you are 30 weeks pregnant.

The doctors go off the first day of your last period. So that the pregnancy can be 40 weeks( which is actually longer than 9 months) Granted, even with the due date they give you or if you know when you conceived( which is hard to do) the baby will come when he/she is ready. I just had my first on oct 19th and he was ten days early according to my due date. They also say you are tech. pregnant 2 weeks before you conceive. Which makes no sense to me. There are a bunch of sites online that can help you understand the doctors math, also What to Expect has a lot of answers:)

You are 13 weeks pregnant. They go by the first day of your last menstrual cycle.

You can also use Naegele's Rule to figure out your due date:

The rule estimates the expected date of delivery (also called EDC, for estimated date of confinement) from the first day of the woman's Last menstrual period (LMP) by adding a year, subtracting three months and adding seven days to that date. This approximates to the average normal human pregnancy which lasts 40 weeks (280 days) from the LMP, or 38 weeks (266 days) from the date of fertilization.

Example:

LMP = 1 Oct 2009

+1 year = 1 Oct 2010

-3 months = 1 July 2010

+7 days = 8 July 2010

Yes, all of it occurred to me, and it feels like Implantation Bleeding. Here is what Implantation Bleeding is? Many ladies listen the time period implantation bleeding used plenty regarding the early levels of being pregnant, however except they acquire explanation on what this phenomenon honestly is then it may be a frightening revel in. What precisely is implantation bleeding? During the early levels of being pregnant the ovum, or fertilized egg, attaches itself to the uterine wall. This constantly happens inside the primary trimester and will routinely intent a little bit quantity of blood to be published. This is the intent of implantation bleeding. The egg honestly attaches itself to the mum’s circulatory process through the wall of the uterus, and that is in which the blood comes from. Some ladies would suppose cramping along side implantation. In a few occasions ladies have already overlooked a interval and are conscious of the being pregnant. Not each lady detects implantation bleeding. Remember that pregnancies may also be regarded flawlessly common whether or not there's any bleeding within the early levels or now not. Many ladies marvel find out how to inform the change among implantation bleeding and bleeding that might be a signal of whatever extra critical. If you revel in mild recognizing – corresponding to best adequate to put on a panty-liner – then it's certainly implantation bleeding. Additionally, if the recognizing is darkish and now not brilliant purple, and the recognizing ends swiftly, this facets to implantation bleeding as good. Keep in brain that this may also be fully common within the first trimester however you will have to determine constantly determine along with your surgeon each time bleeding happens in the course of a being pregnant. There are different motives if the bleeding isn't as a result of implantation. Bleeding past mild recognizing is also a influence of your menstrual cycle, and the lighter drift than common might be precipitated via any quantity of matters adding strain. Changing your beginning manipulate too can intent a difference to your bleeding drift and recognizing can be a signal of illness or abrasions from contemporary sex. When unsure, touch your surgeon.

13 weeks. they go by ur last period

13 weeks. Pregnancy is always measured from your LMP date.

you are considered 13 weeks...

http://www.baby2see.com/development/index.html