I Think I’m Pregnant…How Do I Know For Sure?

This information aims to provide information about confirming your pregnancy. If you have confirmed your pregnancy and have decided to continue with the pregnancy, you may be interested in the information sheet, called ‘I’m Pregnant… What Now?’

If you have been sexually active at any time since your last menstrual period, then you could be pregnant. This is true even if you used contraception as all methods of contraception can be ineffective under certain circumstances.

The following physiological symptoms may be a sign of early pregnancy[1]:

  • Missed period (or an unusually light period)
  • Nausea and/or vomiting
  • Breast changes – tenderness or fullness; enlargement or darkening of areola (coloured area around the nipple)
  • Fatigue (tiredness)
  • Frequent urination

 

While experiencing any or all of these symptoms may indicate that a woman is pregnant, it does not necessarily mean that you are pregnant as these symptoms can occur separate to pregnancy. If you have not been sexually active since your last period, it is not possible that you are pregnant. If you are concerned about any of these symptoms you might like to see a doctor.

How can I confirm my pregnancy?

Pregnancy tests indicate whether a woman is pregnant by detecting ‘human chorionic gonadotropin’ (hCG) levels in the blood or urine. hCG is a hormone produced during pregnancy which enters the maternal bloodstream and urine. The level of hCG in a pregnant woman’s body increases until about 8 weeks of pregnancy[1].

Urine pregnancy tests can be done at home or with a GP (general practitioner) or private midwife. Urine pregnancy tests are often called home pregnancy tests and can be bought from the supermarket or chemist.

 

Taking a home pregnancy test

To indicate that a woman is pregnant, a home pregnancy test detects hCG in the urine at a certain minimum concentration (or amount). hCG is only present in a woman’s urine if she is pregnant, and the test will only return a positive result if it detects the minimum amount of hCG. Therefore, it is very unlikely that a home pregnancy test will show a positive result unless you are actually pregnant

“False negatives”, where the test indicates that you are not pregnant, when you actually are pregnant, are possible under some circumstances. If you take a home pregnancy test in the middle of the cycle, it may be too soon after conception (when the egg is fertilised by the sperm), the concentration of hCG in your urine may be too low for the home pregnancy test to detect. Therefore, the test is likely to tell you that you are not pregnant. However, if you take the test again a few weeks later when the concentration of hCG has increased to the level detectable by the home pregnancy test, then it is likely to tell you that you are pregnant. Some pregnancy tests vary in the amount of hCG they require in order to show a positive result.

Therefore the accuracy of a home pregnancy test depends on [2]:

  • how soon after conception you take the pregnancy test; and
  • the minimum concentration of hCG needed in the urine for the pregnancy test to indicate that a woman is pregnant.

 

To increase the chance that your pregnancy test result is accurate:

  • follow the instructions on the package closely – including testing your urine when you first wake up, as this is when it is most concentrated [3]
  • take the pregnancy test after a missed period (i.e. after you would normally expect your period)[4]
  • repeat the pregnancy test at a later date (at least 2 to 3 days after a missed period) [2]
  • use a home pregnancy test that has a digital display (display indicates test result digitally in words). [5]

 

Taking a pregnancy test with a GP or a private midwife

Some women choose to visit a GP or private midwife to confirm that they are pregnant. GPs and private midwives usually use a urine and/or blood pregnancy test. This urine test is the same as a home pregnancy test. Therefore if a GP or private midwife suggests a urine pregnancy test, it is usually to double-check the results of your home pregnancy test (if you took one). The blood pregnancy test involves having blood taken and sending the sample to be tested in a laboratory. Similar to a urine pregnancy test, the blood pregnancy test measures the hCG hormone in the woman’s blood. Some GPs or private midwives may do a urine pregnancy test before recommending you take a blood test. Others may send you straight for a blood test to confirm your pregnancy, particularly if you have already done a urine test at home. Others may not suggest a blood pregnancy test at all and will instead rely on the urine test.

How can I work out how far along in pregnancy I am?

Before making decisions about your pregnancy, it can be useful to know how far along your pregnancy is. This is often referred to as ‘dating’ your pregnancy. There are generally 2 options for dating pregnancy:

  • LNMP (last normal menstrual period) based calculations
  • Ultrasound dating scan

 

LNMP (last normal menstrual period) based calculations

The LNMP (or LMP) method of pregnancy dating estimates your expected date of birth (or due date) by working forward from the first day of your last normal menstrual period[6]. LMP is the most common way of dating a pregnancy and determining an expected due date, and is based on the assumption that the average pregnancy lasts 280 days from the first day of a woman’s last period[6]. You can calculate this yourself or use an online LMP calculator (there are many available online). Alternatively you can ask your care provider to estimate this for you. Several factors can influence the accuracy of LMP calculations[7]:

  • if a woman cannot remember the date of her LMP [1]
  • if a woman confuses her LMP with midcycle bleeding. Midcycle bleeding is bleeding between periods that is not a true period. Implantation bleeding (small amount of bleeding that can occur when a fertilised egg implants itself into the uterine wall) is a form of midcycle bleeding [1].
  • if a woman has irregular menstrual cycles or cycles that are longer or shorter than 28 days. Some LMP calculations can take into account length of cycle, but not cycle irregularity
  • if a woman has recently used oral contraceptives
  • if a woman is breastfeeding.

 

Ultrasound dating scan

An ultrasound scan (where a small handheld device is used to create a picture of a woman’s uterus and baby during pregnancy) is also commonly used to estimate how many weeks pregnant you are by measuring at the size of the fetus (developing baby). This ultrasound scan is commonly called a ‘dating scan’ and is usually performed early in pregnancy. Dating scans can be used in addition to LMP calculations or may be used instead of LMP calculations (for the reasons discussed above) [7]. To have a dating scan you will need a referral from a GP or midwife.

How do I feel about being pregnant?

While many women are happy to find out they are pregnant, this is not the case for all women. If you are unsure whether you want to become a parent, you can choose to terminate the pregnancy or give your baby up for adoption. The following organisations support women making decisions about their pregnancies and can provide further information on these options:

Additionally the Department of Communities, Child Safety and Disability Services can provide further information on the option of adoption (www.communities.qld.gov.au/childsafety/adoption/).

For many women, finding out they are pregnant is an exciting experience. It can mark the beginning of planning for birth and parenting. It is possible to discuss your maternity care options (including place of birth and type of maternity care provider) with your GP or private midwife if you decide to see him/her for pregnancy confirmation. To prepare yourself for this appointment or to begin thinking about your maternity care options, you might like to read the “I’m pregnant, now what?” information sheet.

Even if your pregnancy is planned or very much wanted, it is normal to have mixed feelings about the future. For any woman, some worry is normal, however if you feel very fearful or anxious about your pregnancy or about giving birth, you might like to seek support. For some women, this anxiety or fear stems from a previous negative experience, e.g. sexual assault/abuse or traumatic birth [8, 9]. Other women experience anxiety or fear simply because pregnancy and birth is unfamiliar. Therefore you may find it helpful to think about your emotional support needs when choosing your model of care. There are also many other organisations that offer counselling and social and emotional support to pregnant women. You can find them by searching on the internet for “childbirth education”, “birth preparation” or “prenatal yoga”.

Where did this information come from?

1. Pillitteri, A., Maternal & Child Health Nursing: Care of the Childbearing & Childrearing Family. Vol. 6. 2010: Lippincott Williams & Wilkins.

2. Cole, L.A., et al., Sensitivity of Over-the-Counter Pregnancy Tests: Comparison of Utility and Marketing Messages. Journal of the American Pharmacists Association, 2005. 45(5): p. 608-615.

3. Bastian, L.A., et al., Diagnostic Efficiency of Home Pregnancy Test Kits: A Meta-Analysis. Archives of Family Medicine, 1998. 7(5): p. 465-469.

4. Cole, L.A., et al., Accuracy of home pregnancy tests at the time of missed menses. American Journal of Obstetrics and Gynecology, 2004. 190(1): p. 100-105.

5. Tomlinson, C., J. Marshall, and J.E. Ellis, Comparison of accuracy and certainty of results of six home pregnancy tests available over-the-counter. Current Medical Research and Opinion, 2008. 24(6): p. 1645-1649.

6. Lynch, C.D. and J. Zhang, The research implications of the selection of a gestational age estimation method. Paediatric and Perinatal Epidemiology, 2007. 21: p. 86-96.

7. Johnson, S., et al., Home pregnancy test compared to standard-of-care ultrasound dating in the assessment of pregnancy duration. Current Medical Research and Opinion, 2011. 27(2): p. 393-401.

8. Gardner, P.S., Previous traumatic birth: An impetus for requested cesarean birth. Journal of Perinatal Education, 2003. 12(1): p. 1-5.

9. Heritage, C., Working with childhood sexual abuse survivors during pregnancy, labor, and birth. Journal of Obstetric, Gynecologic and Neonatal Nursing, 1998. 27(6): p. 671-7.

 

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