There are several methods of confirming pregnancy in a woman by checking different hormone levels. Most commonly used hormone is the beta subunit of human chorionic gonadotropin (HCG). Beta HCG is a hormone which is produced by the human placenta.
Right Time To Take Pregnancy Test After Missed Period
The tests include urine HCG test and serum HCG test. Taking a pregnancy test after a missed period should be timed correctly to detect the pregnancy accurately. To detect beta HCG in both urine and serum the test should be performed 1-10 days after a missed period in a woman who was having regular cycles.
When this time is converted to the period of gestation, it can be stated as 5 weeks. Since the placental implantation takes place at a period of gestation of 3-4weeks, the test should be timed at this particular period. Quantitative serum assays can detect HCG levels as low as 1 mIU/ml.
But urine HCG strips can only detect HCG levels >10 mIU/ml since it is a qualitative assay. Serum HCG is the best early test to detect pregnancy. If the serum HCG level is checked serially, doubling of the HCG level in every 48 hours will support more towards a viable fetus.
The amount of beta HCG produced by the placenta increases at this rate with the period of gestation in a viable fetus. If the test is done before missing a period, at a period of amenorrhea of 3 weeks there is a possibility of urine HCG test to become negative.
The urine HCG test can be performed at home. If you are planning to have a baby, it is best to note the day of your last menstruation. This helps you detect the missed period correctly without any delay. Even though the serum HCG is more sensitive than urine HCG, most women prefer urine HCG since it is simple and non-invasive.
Reasons To Take Pregnancy Test After Missed Period
The basis of performing a pregnancy test after a missed period should be clearly understood. Menstruation is a physiological process happening in every woman’s body. In the menstrual cycle, there are two phases. They are called as follicular phase and the luteal phase. During the follicular phase, the ovum matures and ovulates on the 14th day of the cycle. Then the luteal phase starts. During this phase, the uterine endometrium thickens in order to accept an embryo if the ovum gets fertilized by a sperm.
But when there is no fertilization, the endometrium starts to shed off on the last 3days of the cycle. This shedding off of the endometrium is what the woman experience as menstruation. When the ovum meets a sperm inside the woman’s reproductive system the endometrium will continue on thickening to accept the embryo and the woman will experience a missed period.
What Kind Of Preparation Is Needed?
If you are planning to have a baby, you should start noting down your menstrual periods. If they are regular, it is quite easy to detect a missed period. But if the periods are irregular, you need to note down the dates for a few months.
Also, know when you can take a pregnancy test with irregular periods and how it can be done. In irregular cycles, it is recommended that you should get the urine HCG test 36 days after her last period or 4 weeks after the sexual intercourse. There are urine HCG test kits, which are available to buy. Initially, you should read and understand the instructions mentioned in the kit.
There is a specific duration of time to wait before reading the result. This duration might vary among different brands. It is recommended to use an early morning urine sample. Or at least she should not have voided urine for 4 hours duration. Don’t drink too much fluids to increase the amount of urine, because it may dilute the concentration of HCG present in urine. Dip the kit/strip in urine and wait for sometime as mentioned in the instructions. You will find a control showing what a negative test result will look like.
Understanding the principle behind taking a pregnancy test after a missed period and the correct timing of the test will give the results more accurately. But there is always a possibility of false negativity of urine HCG test, in conditions like ectopic pregnancies. A woman should be advised to seek medical advice when she is sure about missing her periods and still the test comes as negative. Women should undergo a serum HCG test to detect suboptimal levels of HCG. Early detection of pregnancy will allow the woman to have comprehensive antenatal care, which leads to a healthy delivery.
Dr. Chauturi is an experienced writer specializing in English language and Medical Sciences, and degree holder in Medicine, Bachelor of Surgery at University of Sri Jayewardenepura currently awaiting her internship.