When exactly did I get pregnant?

Calculating gestational age and when you got pregnant can provide a lot of information about your health during pregnancy. 

An estimated due date is calculated based on a 28-day menstrual cycle, but some cycles are longer or shorter than 28 days. Also, the time of ovulation varies from person to person. For women with regular periods, conception usually takes place 11-21 days after the first day of the last period

Reports show that about 50% of women will accurately recall their last menstrual period (LMP). And since ovulation days vary for each person, pregnancy dating without first trimester ultrasound is less accurate for determining a due date or how many weeks pregnant.

Using the first day of the last menstrual period with a formula of adding 280 days, may cause errors of more than 2 weeks. 

In the 1970s, doctors started using ultrasound measurements for the most reliable way to define gestational age. Over the years, medical providers have used ultrasound to determine how far along the pregnancy is. An ultrasound can also determine if the pregnancy is growing in the right place. 

Urine based pregnancy tests are generally accurate, but they cannot tell how far along you are. An ultrasound measurement of the pregnancy size in 13 weeks and 6 days is the most accurate way to confirm gestational (or pregnancy) age. 

Obstetrical doctors agree that ultrasound-established dates are more preferable over period dates, and the later the ultrasound is done, the less accurate the due date is.  

Getting a blood test to check for the rising level of Human Chorionic gonadotropin (HCG) can also help to determine how far along the pregnancy is. HCG can be detected in the mother’s blood and urine between 6 and 14 days after fertilization. 

Why do I need an ultrasound?

To find out how far long you are before considering all your pregnancy options, an ultrasound will determine if the pregnancy is viable. As many as 1 in 4 of pregnancies do not carry to term.  Some women are pregnant and lose the pregnancy before they realize it.   Some pregnancies are “chemical” and end before 5 weeks. About 2% of pregnancies are ectopic or growing outside of the uterus.  

Since early pregnancy loss can be determined by ultrasound, having an ultrasound to confirm your pregnancy is a great step after the pregnancy test.  

To schedule a FREE ultrasound or for more information on ultrasound services, click HERE.