Pregnancy tests can give a positive result 8 to 10 days after sex if you are pregnant.But there are a few things you need to keep in mind when testing for pregnancy. Testing early has its limitations. Over-the-counter tests for pregnancy are usually sticks you dip into urine.
If the sensitivity of a stick is low it needs a higher amount of hormones to light up. If the sensitivity of a stick is high, it needs only a small amount of hormones to give a positive result. So, very early in the pregnancy a good sensitive urine pregnancy test will give a positive result before a less sensitive one.
Ultrasound scans can pick up a pregnancy after about 3 to 5 weeks. Initially only a small sac is all that is seen. A small fetal pole appears next followed by a visible heartbeat. Before the pregnancy can be seen with a scan, the pregnancy test becomes positive.
Ovaries release an ovum on around day 14 of the cycle. An unfertilized ovum can remain viable in the female genital tract for about 5 to 8 days.
Sperm deposited in the vagina take around two days to reach the ovum at the fertilization site. Fertilization of the ovum usually occurs in the ampulla (middle part) of the fallopian tubes. The fertilized ovum takes about 6 to 7 days to reach the uterus.
The placenta develops as implantation of the fertilized ovum (the Zygote) progresses. The placenta secretes hCG since implantation.
HCG keeps a structure called corpus luteum in the ovary active. The corpus luteum secretes progesterone to maintain the inner lining of the uterus (endometrium) and in turn the pregnancy. If implantation does not occur, there will be no hCG to maintain the corpus luteum. It regresses 9 days after ovulation. Progesterone levels drop and the inner lining of the uterus separates from the uterine wall. Menstruation begins around day 28.
According to normal reproductive physiology the pregnancy test will be positive around 8 days after unprotected sex if you are pregnant. But...
A certain leading brand in the market claims it will detect pregnancies in 69% of women four days before the missed period. Three days before, it will detect around 83% and two days before 93% of the pregnancies. This means 7% will not be detected. Therefore, it is important to remember that if one test says you are not pregnant on the 8th day after sex, you need to wait a few more days and then recheck.
- Obstetrics by ten teachers
- Gynecology by ten teachers
- A review of medical physiology by Ganong
- Photo courtesy of SteadyHealth