How To Know When You Conceived – More Simple Than You Think

When I discovered that I was pregnant with my first child, I felt like a dog with two tails. Every day I was so buzzing for the day that I would finally deliver that I even wanted to know the day I conceived so I could determine for how long I had been pregnant.

Many women too always ask themselves this question, “When did I conceive?” upon discovering that they are pregnant. Some even wonder if it is possible to tell the date that a woman conceived.

Although you cannot tell precisely the exact date and time that you conceived, you can calculate and get an estimate of the dates around which your baby was conceived.

First of all, conception is the act of fertilisation of the egg by a sperm cell inside one of the fallopian tubes. This usually occurs when a woman has sex during her fertile time which is usually the period that she has ovulated.

After fertilisation, the ovum hardens to prevent other sperms from getting attached to it. The sperm and the ovum form a ball of cells that will travel down to the uterus and get attached to the uterine walls in a process called implantation.

There are several ways you can estimate the dates when you conceived, they include:

  • Making calculations using your menstrual cycle length.
  • Using ovulation predictor kits.
  • Using BBT charts.
  • Making calculations using your estimated due date.
  • Through ultrasound.

Calculations Using Your Menstrual Cycle Length

Pinpointing the date around which you conceived is possible by making calculations based on the length of your menstrual cycle. It takes 28 days for a woman to go through a normal menstrual cycle.

First of all, you can start by marking the date of the first day of your last period before you got pregnant. From the date you have marked, count 28 days forward to get the date you expected to receive your next period. Mark that date on your calendar.

Next, count 14 days backwards from that day that you were to experience your period but didn’t, and mark it on your calendar. There you have it, the day you conceived is within two days before or after that day. If your menstrual cycle is irregular, it will be difficult to determine the date you conceived using this method.

Using Ovulation Predictor Kits


The Ovulation Predictor Kits can be used to determine the level of the pituitary luteinizing hormone by testing your urine.

When you ovulate, the level of this hormone increases and can be detected in your urine. If you carried out such a test during your cycle and it tested positive, then this is the time around which you were likely to conceive since it is the fertile period.

Using BBT Charts

Some women usually keep a basal body temperature chart during their cycles. This chart can be useful in the estimation of your date of conception since it helps to determine the day you ovulated from which you can easily tell the date you conceived.

The body temperature doesn’t usually go beyond 98 degrees Fahrenheit. The temperature usually goes above 98 degrees Fahrenheit when a woman ovulates. You can, therefore, tell the day that you ovulated by checking the last day on your BBT chart that your body temperature was below 98 degrees Fahrenheit. The day of conception lies within two days after your ovulation date.

Making Calculations Using Your Estimated Due Date

A normal pregnancy usually lasts between 38 weeks to 40 weeks. Once you have gone to your doctor and he or she has indicated to you your due date on which you are likely to deliver, you can, therefore, answer the question “When did I conceive?”

It’s simple, just subtract 38 weeks or 266 days from your due date and what you get is an estimation of the time that you conceived.

Measurements From Ultrasound

Between the 8th week and the 20th week of pregnancy, ultrasounds can be performed to determine how the baby is doing and to get measurements that doctors can use to determine your baby’s gestational age.

Gestational age differs from foetal age in that it is the age of your pregnancy from the last day you missed your pregnancy.

Foetal age is the age of the foetus from the moment you conceived and is two weeks younger than the gestational age. Based on the measurements from the baby’s legs and arms, doctors can determine your baby’s gestational age.

You can then subtract two weeks from the estimated gestational age to get the foetal age. This gives you the estimated date around which you might have conceived.

From our discussions above, it is, therefore, obvious that by knowing the period you ovulated, you can easily determine when you conceived. Due to the hormonal shifts that usually occur in the body when you ovulate, you will definitely notice when you ovulate.

The following signs and symptoms will let you know of the time you ovulate so that you will be able to determine the date that you conceived.

Cervical Mucus Changes

Due to the increase in the production of oestrogen as you near ovulation, the cervix will produce more stretchy and clear mucus to facilitate the swimming of sperms.

The day you notice that the mucus in your vagina is stickier and clear, just know that you are in your fertile phase. If you had noticed such changes before discovering that you are pregnant, you would be able to tell the date you might have conceived.

Breast Tenderness

Right before you ovulate, the levels of hormones increase in your body which will make your nipples very sensitive. If you get pregnant, then it is likely that you conceived around this time.

Mild Pelvic Pain

Some women can tell when they ovulate. You might feel some mild lower abdominal pain in the side of the ovary that has released the ovum.

Libido Changes

When you ovulate, the increase in hormonal levels will make your sexual drive increase. You may notice that at certain periods of your cycle, which is usually on the 14th day of your cycle, your sex drive is always higher than usual.

Is It That Important To Know When You Conceived?

Research shows that most of the time, usually 70% of the time, the due dates given by doctors are usually off by one or two weeks. Most doctors may recommend induction of labour based on incorrect estimation dates when your baby does not come out on the indicated due date.

It is, therefore, important to know the date you conceived so that your due date can be accurately established to avoid having a C-section which may come with some complications.


Altogether, when a woman gets pregnant, her life may become a cocktail of excitement and anxiety at the same time. Questions will start running through your mind, some of which you may find answers to, and some of which you won’t find answers to. Questions like “When did I conceive?” may pop into your head.

With the above-discussed methods, you and your doctor can estimate almost accurately the date that you conceived so that they can accurately establish your due date.

Kristi Cathey

Hi everyone! My name is Kristi Cathey and I’m glad you found your way to my blog. I am a mother of 3 beautiful angels. This blog was created in order to share my personal experiences in baby care and general health care for pregnant women. If you'd like to get in touch with me, please contact me by sending me an email via Welcome to

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