Skip to main content

I think I’m pregnant but I don’t know the day of my last period.

Can you help me?

Yes, we can.  Pregnancy is usually measured from the first day of your last period.  Knowing this date lets you know how far along you are in the pregnancy, which can be helpful as you make decisions about the pregnancy and plan for your future.

What if I don’t know the date of my last period?

We will help you figure it out. There are two methods of determining how far along you are in the pregnancy:  an ultrasound or a blood test.  We provide first trimester ultrasounds at the Community Pregnancy Center, free of charge.  If you would rather have a blood test, we can help you find a provider and/or help you sort through health insurance or Medicaid information.

How does an ultrasound show how far along I am?

The nurse or sonographer will take ultrasound pictures of your uterus and the surrounding area and take measurements. We will measure baby if it is large enough or just measure your uterus if baby is too small to measure.  A pregnant uterus begins to change as soon as you get pregnant and those changes can be measured in as little as two to three weeks past conception.  Using standardized data, the ultrasound machine will predict a due date and make an estimate of the progress of the pregnancy.

How does a blood test show how far along I am?

The blood test measures human chorionic gonadotropin (hCG), a hormone produced by embryonic cells and the placenta.35  The blood levels of hCG rise rapidly in early pregnancy and give an indication of how far along you are.   It won’t give you an exact date, but it will give a general idea in most cases. 36

Why do I need know the date of my last period?

The first day of your last period (abbreviated LMP for Last Monthly Period) is just a handy number.  You are not actually pregnant then.  Many women do know when their period was, and using the average monthly cycle of 28 days, we estimate conception to have occurred on day 14 of the cycle.  We count 40 weeks from the LMP to get a due date.  Lost in the math? The folks at explain it well.

Do you want to know how pregnant you are so you can make some decisions about this pregnancy? We can help.  Call today to make an appointment to talk to one of our nurses.  We will do a free pregnancy test, answer your questions, and help you figure out what comes next.

If you do not live in Alaska, will help you find a pregnancy resource center near you.

Contact us today to make an appointment!