If you recently found out you are pregnant you might be wondering, “What day did I get pregnant?” 

There are several ways to help figure out when you conceived. While some steps are more reliable than others, here are a few tools to help you get started in figuring out what day you might have gotten pregnant. 

Remember that a healthcare provider will be able to give you a more accurate answer at an ultrasound appointment. 

What day did I get pregnant?

1. Track when you ovulated

In general, women can only conceive when ovulating. Ovulation is the release of an egg for potential fertilization. You can track your ovulation through an app like Flo, or you can go by your symptoms. 

Signs of ovulation include: 

  • Change in cervical mucus – becomes clear, wet, and stretchy 
  • Increased sex drive 
  • Light cramping on one side of the lower abdomen  
  • Bloating 
  • Breast tenderness 


Track ovulation

Conception usually occurs within 11-21 days from the start of your last period during ovulation. In an average 28-day menstrual cycle, ovulation occurs around day 14. That’s 2 weeks after your period has started.

Pregnancy can happen if intercourse occurs during the five days leading up to ovulation or the 24 hours after ovulation. If you can pinpoint when you may have ovulated, it can help determine the day you got pregnant. 

All women’s bodies are unique and each menstrual cycle is different. Some women have irregular periods, some may ovulate closer to or further from their periods, and some might not know when their last period was. 

It is difficult to pinpoint the exact day of conception from the presumed ovulation date alone. An ultrasound is a more accurate way to determine when you may have conceived. 

2. Track the first day of your last menstrual period (LMP)

A baby’s gestational age is determined by the number of weeks since the last menstrual period. 

There are 40 weeks in a pregnancy. Pregnancies are dated by the first day of the last menstrual period. However, if your ovulation is different from the typical 28-day cycle, the LMP is not the most accurate way to calculate the timing of conception. 

You can get the most accurate timing of conception by having an accurate due date. By having an accurate due date, you will be able to calculate your conception date.  

To calculate the conception date: 

Conception = Due Date – 280 days 

We can help you figure out your due date based on an ultrasound which confirms whether the pregnancy dating by the last menstrual period is correct.  

When did I get pregnant

What if I don’t know when my last period was?  

If you don’t keep track of your periods or have an irregular cycle, it can be even more challenging to figure out what day you became pregnant. You will have to make the best guess on when your last period was.  

Not completely sure if you’re pregnant? Reach out to our staff at LifeSpring to confirm your pregnancy with a medical-grade pregnancy test and ultrasound today. 

3. Determine the days you had intercourse 

Pinpoint which days you had intercourse. This can help you figure out the days you might have had sex around ovulation. Sperm can live up to 5 days waiting to fertilize the egg. This can make it especially tricky to figure out who is the father if you have had more than one sexual partner during ovulation.

If you have had multiple sex partners within the same menstrual cycle, the only way to be 100% sure of the identity of the father is by a paternity test.  

4. Schedule an ultrasound 

An ultrasound is the most accurate way to calculate gestational age and help determine when you may have conceived. Ultrasounds measure the fetus to estimate how far along you are. The fetus can be measured through an ultrasound as early as 5 to 6 weeks after your last menstrual period.  

Comparing the measurement from the ultrasound with the first day of your last period can help your healthcare provider estimate your date of conception. Ultrasounds can also detect any abnormalities, health risks, ectopic pregnancies, and confirm if pregnancy is viable.  

What are my next steps?

Schedule an ultrasound

Scheduling an ultrasound early in your pregnancy confirms an accurate gestational age to help you figure out when you conceived.

At LifeSpring, we offer free ultrasounds. We are a safe and confidential place for you to talk through potential conception dates and pregnancy options. We are here for you.  

Schedule a free ultrasound today.