Pregnancy Test Before Period: Is It Accurate?

Pregnancy test before period missed

Last updated on July 28th, 2018 at 04:35 am

Pregnancy test before period may or may not be accurate depending on the type of kit used and when test is done. If you test positive for pregnancy before your period,  then its likely you are pregnant. However, if you’re negative, it still does not exclude pregnancy.

Do you have signs of pregnancy — breast swelling, body weakness, increased sensitivity to smell and taste?

Are you worried you may be pregnant after an unprotected intercourse 3 weeks ago?

Though pregnancy test before period is likely not accurate, some kits can detect pregnancy about 5 days before your period.

This article explains the risk, accuracy and the best time to get a pregnancy test done.


How does pregnancy test work?

Pregnancy test works by checking for the HCG (human chorionic gonadotropin), which is found in both urine and blood during early pregnancy.

After fertilization and implantation, your blood and urine HCG levels continue to rise, doubling every 48 – 72 hours. Over the counter pregnancy kits can detects this HCG rise in your urine.

Blood samples and ultrasound can also detect pregnancy. While ultrasound may show your baby 4 weeks after missed period, blood test can detect pregnancy very early. However, both test cannot be carried out at home.

How does pregnancy or implantation occur?

During your period cycle, the ovaries releases egg into the Fallopian tube for fertilization. This release of egg is called ovulation.

This egg may be fertilized in the fallopian tube by the man’s sperm.

After fertilization, it takes some days for the embryo to be transported back to the uterus where it is attached to the uterine endometrium. This attachment is called implantation and may cause some women to have light spotting before period and cramping.

After implantation, HCG levels in blood and urine begin to rise which is detected during your pregnancy test.

Understanding your ovulation signs and symptoms makes it easy to know when ovulation takes place and when you may have signs of pregnancy. This is because implantation bleeding occurs about 6 – 12 days after ovulation while your next period occurs 14 to 16 days after ovulation.

Some of the sign of ovulation are

  • Clear white stretchy discharge before ovulation
  • Increased basal body temperature
  • Ovulation cramps and pain
  • Breast swelling and pain
  • Increased sexual drive

Signs of a successful implantation or pregnancy are

  • Implantation bleeding
  • Implantation cramping
  • Breast soreness or tenderness
  • Food aversion or craving
  • Nausea
  • Increased sensitivity to smell
  • Increased frequency of urination
  • Sometimes constipation or increased farting
  • Increase vaginal discharge

These are very early symptoms of pregnancy. Having pregnancy test done immediately after implantation may be inaccurate due to low level of HCG hormones. Some pregnancy test kits can detect pregnancy with a 99 percent accuracy a day before expected period.

It’s also possible to predict your next period if you have

  • Cramping before periods
  • Headache before period
  • Breast pain and swelling before period
  • Low back pain before periods

However, these menstrual period symptoms may sometimes be confused as pregnancy.


When is the best time to test for pregnancy?

Test accuracy for pregnancy depends on the type of kit used.

First response kit

First response kit can detect pregnancy with a 66 percent accuracy 5 days before your period. This rises to 99 percent a day before your period.

Clear blue pregnancy test

Clear blue pregnancy test detects pregnancy about 4 days before your next period. It is more accurate on the day before your period. If your are pregnant, it simply shows a plus sign “+” sign or “-” sign if you are not pregnant.

Super drug early pregnancy test

This pregnancy test can detect if you are pregnant 4 days before your period.

So, whats the best time to take a pregnancy test?

The best time to test for pregnancy is a week after your missed period.

However, there are many other reason why you could miss your period that is not pregnancy.

Stress, long term illness and severe weight loss with more than 10 percent of body weight may cause your period to come 1, 2, 3, 4 or 5 days late.

Other conditions that could delay your period are

  • Birth control pills
  • Strenuous exercise
  • Peri-menopause
  • After morning pills
  • Late ovulation


FAQs about pregnancy test before missed period

These are some frequently asked questions about pregnancy test. Let us know your questions below.

How long does it take to get results with a pregnancy test

Most home pregnancy test use urine sample and results are available in one to five minutes. You should use early morning concentrated urine for more accurate results.

How to run a pregnancy test at home

  • Buy a pregnancy test kit
  • Wait till in the morning and collect your urine in a container
  • Hold your test strip and dip into the urine sample

Results will be out in less than 5 minutes. Always check the instructions on your pregnancy kits before testing.

How accurate are pregnancy test before period?

Pregnancy test before your period is likely inaccurate. According to first response, accuracy is about 66 percent when test is done 5 days before your period and increases as you get closer to your expected period.

Women with late ovulation, due to stress or eating disorders, will have a negative pregnancy test. This is because implantation has not occurred yet. It is important you wait till at least a week after your expected period to get a pregnancy test done.

Can i have a false positive pregnancy test before period?

Yes. Its possible to test positive for pregnancy when actually you are not. This occurs if you are

  • Taking medications like clopromazine or methadone
  • Taking fertility injections that increases body HCG level.
  • Reading you test strip results more than the stipulated time given. Its important you follow instructions that come with your strips. False positive results occurs as evaporated lines on your strip.
  • Using an expired pregnancy strip. You should check your strips before testing to confirm the expiry date.
  • Or if you have cancer or liver disease

Can i have a false negative pregnancy test before period?

Yes. If your pregnancy test is done too early, it may be negative. You should wait a week after your missed period and get your test done again.

Pregnancy test 3, 4, 5, 6 days before missed period, Is it Accurate?

If you want to check your pregnancy status anytime before missed period, then you can get a strip. However, test done 3, 4, 5, 6 days before period is inaccurate.

Some pregnancy strip may test may detect pregnancy early. However, if you are negative, you should run a test after some days.

When to take pregnancy test after missed period?

The best time to take a pregnancy test after missed period is a week. Cant wait? Then get a pregnancy test today. If still negative, then wait for a while and recheck again.

Is it possible to have positive pregnancy test at 3 weeks?

Yes. Its possible you could be pregnant 3 weeks after start of your last period.

Menstrual cycle length vary among women. The normal length of the menstrual cycle is 21 to 35 days.

It difficult to test positive to pregnancy in 3 weeks if you have a long menstrual cycle. However, women with shorter menstrual cycle can test positive to pregnancy by the third week.


Now its your turn. Is your pregnancy test negative before your period? Are you worried about it? Let us know if we could help.


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