A modern pregnancy test

A pregnancy test is a test to determine whether or not a woman is pregnant. Image File history File linksMetadata Download high-resolution version (1000x480, 105 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Pregnancy test Metadata This file contains additional information, probably added from the digital camera or scanner used to... Image File history File linksMetadata Download high-resolution version (1000x480, 105 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Pregnancy test Metadata This file contains additional information, probably added from the digital camera or scanner used to... A pregnant woman near the end of her term Pregnancy is the carrying of one or more embryos or fetuses by female mammals, including humans, inside their bodies. ...

Modern tests

The earliest test for pregnancy is a rosette inhibition assay for early pregnancy factor (EPF). EPF can be detected in blood within 48 hours of fertilization.^[1] However, testing for EPF is expensive and time consuming. Enzyme assays are laboratory methods for measuring enzymatic activity. ... Early pregnancy factor (EPF) or early conception factor (ECF) is a protein associated with mammalian embryos shortly after fertilization. ... A sperm cell fertilizing an ovum This article is about reproduction in organisms. ...

Most chemical tests for pregnancy look for the presence of the beta subunit of hCG or human chorionic gonadotropin in the blood or urine. hCG can be detected in urine or blood after implantation, which occurs six to twelve days after fertilization.^[2] Quantitative blood (serum beta) tests can detect hCG levels as low as 1 mIU/mL, while urine tests have published detection thresholds between 20 and 100 mIU/mL, depending on the brand.^[3] Qualitative blood tests generally have a threshold of 25 mIU/mL, and so are less sensitive than some available home pregnancy tests. Human chorionic gonadotropin (hCG) is a peptide hormone produced in pregnancy, that is made by the embryo soon after conception and later by the syncytiotrophoblast (part of the placenta). ...

With obstetric ultrasonography the gestational sac can sometimes be visualized as early as four and a half weeks of gestation (approximately two and a half weeks after ovulation) and the yolk sac at about five weeks gestation. The embryo can be observed and measured by about five and a half weeks. The heartbeat may be seen as early as 6 weeks, and is usually visible by 7 weeks gestation.^[4][5] Obstetric sonogram of a fetus at 16 weeks. ... The gestational sac is the only available intrauterine structure that can be used to determine if an intrauterine pregnancy (IUP) exists, until the embryo is identified. ... Gestational age is age of a fetus (or newborn infant) from presumed conception. ... The yolk sac is the first element seen in the gestational sac during pregnancy, usually at 5 weeks gestation. ... For other uses, see Embryo (disambiguation). ...

History

A physician administers a urine test in The Doctor's Visit by Jan Steen.^[6]

The ancient Egyptians watered bags of wheat and barley with the urine of a possibly pregnant woman. Germination indicated pregnancy, and based on what type of grain sprouted they predicted the gender of the fetus. Hippocrates suggested that a woman who had missed her period should drink a solution of honey in water at bedtime. Resulting abdominal distention and cramps would indicate the presence of a pregnancy. Avicenna and many physicians after him in the Middle Ages performed uroscopy, a nonscientific method to evaluate urine. Selmar Aschheim and Bernhard Zondek introduced testing based on the presence of hCG in 1928.^[7] Image File history File links Download high-resolution version (881x1027, 152 KB) Jan Steen (1626-1679). ... Image File history File links Download high-resolution version (881x1027, 152 KB) Jan Steen (1626-1679). ... // Steen was born in Leiden, where his well-to-do, Catholic family had run the tavern The Red Halbert for several generations. ... Hippocrates of Cos II or Hippokrates of Kos (ca. ... This article needs additional references or sources to facilitate its verification. ... The Middle Ages formed the middle period in a traditional schematic division of European history into three ages: the classical civilization of Antiquity, the Middle Ages, and modern times, beginning with the Renaissance. ... Uroscopy is the historic medical practice of visually examining a patients urine for pus, blood, or other symptoms of disease. ... This article or section does not cite its references or sources. ... Human chorionic gonadotropin (hCG) is a peptide hormone produced in pregnancy, that is made by the embryo soon after conception and later by the syncytiotrophoblast (part of the placenta). ...

In the Aschheim and Zondek test an infantile female mouse was injected subcutaneously with urine of the person to be tested, and some time later the mouse was killed and dissected. Presence of ovulation indicated that the urine contained hCG and meant that the person was pregnant. A similar test was developed using immature rabbits, the rabbit test. Here, too, it was necessary to kill the animal to check its ovaries. An improvement arrived with the frog test that was still used in the 1950s. A female frog was injected with serum or urine of the patient. If the frog produced eggs within the next 24 hours, the test was positive. In the frog test, the animal remained alive, and could be used again. Feral mouse A mouse (plural mice) is a rodent that belongs to one of numerous species of small mammals. ... Ovulation is the process in the menstrual cycle by which a mature ovarian follicle ruptures and discharges an ovum (also known as an oocyte, female gamete, or casually, an egg) that participates in reproduction. ... The rabbit test was an early pregnancy test developed in 1927. ... Distribution of frogs (in black) Suborders Archaeobatrachia Mesobatrachia Neobatrachia - List of Anuran families The frogness babe is an amphibian in the order Anura (meaning tail-less from Greek an-, without + oura, tail), formerly referred to as Salientia (Latin saltare, to jump). ... In most birds and reptiles, an egg (Latin ovum) is the zygote, resulting from fertilization of the ovum. ...

Timing of test

False negative readings can occur when testing is done too early. Quantitative blood tests and the most sensitive urine tests usually detect hCG shortly after implantation, which can occur anywhere from 6 to 12 days after ovulation.^[2] Less sensitive urine tests and qualitative blood tests may not detect pregnancy until three or four days after implantation. Menstruation occurs on average 14 days after ovulation, so the likelihood of a false negative is low once a menstrual period is late. Type I errors (or α error, or false positive) and type II errors (β error, or a false negative) are two terms used to describe statistical errors. ... Ovulation is the process in the menstrual cycle by which a mature ovarian follicle ruptures and discharges an ovum (also known as an oocyte, female gamete, or casually, an egg) that participates in reproduction. ... Menstrual cycle. ...

Ovulation may not occur at a predictable time in the menstrual cycle, however. A number of factors may cause an unexpectedly early or late ovulation, even for women with a history of regular menstrual cycles. Using ovulation predictor kits (OPKs), or charting the fertility signs of cervical mucus or basal body temperature give a more accurate idea of when to test than day-counting alone. Menstrual cycle The menstrual cycle is a recurring cycle of physiological changes that occurs in the females of human beings and great apes. ... Fertility Awareness (FA) is the practice of observing one or more of a woman’s primary fertility signs to determine the fertile and infertile phases of her menstrual cycle. ... Schematic frontal view of female anatomy The cervix (from Latin neck) is the lower, narrow portion of the uterus where it joins with the top end of the vagina. ... One of the many changes that take place in a womans body during her menstrual cycle is an increase in body temperature at the onset of ovulation. ...

The accuracy of a pregnancy test is most closely related to the day of ovulation, not of intercourse. It is normal for sperm to live up to five days after intercourse^[8] in the fallopian tubes, waiting for ovulation to occur.^[9] It could take up to twelve further days for implantation to occur, and another three or four days for hCG to rise to detectable levels—meaning false negatives may occur for up to three weeks after the act of intercourse that caused the pregnancy.

False positives

Evaportation lines may appear on many home pregnancy tests if read after the suggested 3–5 minute window or reaction time, independent of an actual pregnancy. Therefore, it is imperative that a pregnancy test be interpreted within the reaction time specified by the test manufacturer.

A woman who has been given an hCG injection as part of infertility treatment will test positive on pregnancy tests, regardless of her actual pregnancy status. Common infertility drugs like clomid do not contain the hCG hormone.^[10]

When taken according to package directions, by women who have not received an hCG injection, false positive pregnancy test results are rare. Some diseases may cause a false positive pregnancy test: choriocarcinomas, IgA deficiencies, heterophile antibodies, enterocystoplasties, gestational trophoblastic diseases (GTD), gestational trophoblastic neoplasms (GTN), testicular germ cell malignancies, and even other forms of cancer, e.g. lung cancer.^{[citation needed]} Type I errors (or α error, or false positive) and type II errors (β error, or a false negative) are two terms used to describe statistical errors. ... Choriocarcinoma is a rare cancer of the placenta, curable by chemotherapy. ... Selective immunoglobulin A (IgA) deficiency is a relatively mild genetic immunodeficiency. ... Heterophile is an alternate term to heterosexual and once competed with it for currency, but only did so successfully in Scandinavia. ... Gestational trophoblastic disease — usually referred to as a mole — is a very rare abnormality of pregnancy in the reproductive female that involves abnormal trophoblast proliferation. ... Lung cancer is the malignant transformation and expansion of lung tissue, and is the most lethal of all cancers worldwide, responsible for 1. ...

Viability

Pregnancy tests may be used to determine the viability of a pregnancy. Serial quantitative blood tests may be done, usually 2–3 days apart. Below an hCG level of 1,200 mIU/ml the hCG usually doubles every 48–72 hours, though a rise of 50–60% is still considered normal. Between 1,200 and 6,000 mIU/ml serum the hCG usually takes 72–96 hours to double, and above 6,000 mIU/ml, the hCG often takes more than four days to double. Failure to increase normally may indicate an increased risk of miscarriage or a possible ectopic pregnancy. Miscarriage or spontaneous abortion is the natural or accidental termination of a pregnancy at a stage where the embryo or the fetus is incapable of surviving, generally defined at a gestation of prior to 20 weeks. ...

Ultrasound is also a common tool for determining viability. A lower than expected heart rate or missed development milestones may indicate a problem with the pregnancy.^[5] Diagnosis should not be made from a single ultrasound, however. Inaccurate estimations of fetal age and inaccuracies inherent in ultrasonic examination may cause a scan to be interpreted negatively. If results from the first ultrasound scan indicate a problem, repeating the scan 7–10 days later is reasonable practice.^[4] Obstetric sonogram of a fetus at 16 weeks. ...

References

1. ^ Fan XG, Zheng ZQ (1997). "A study of early pregnancy factor activity in preimplantation". Am. J. Reprod. Immunol. 37 (5): 359-64. PMID 9196793. 
2. ^ ^{a b} Wilcox AJ, Baird DD, Weinberg CR (1999). "Time of implantation of the conceptus and loss of pregnancy.". New England Journal of Medicine 340 (23): 1796–1799. PMID 10362823. 
3. ^ Waddell, Rebecca Smith (2006). FertilityPlus.org. Home Pregnancy Test hCG Levels and FAQ. Retrieved on 2006-06-17.
4. ^ ^{a b} Woo, Joseph (2006). Why and when is Ultrasound used in Pregnancy?. Obstetric Ultrasound: A Comprehensive Guide. Retrieved on 2007-05-27.
5. ^ ^{a b} Boschert, Sherry (2001-06-15). "Anxious Patients Often Want Very Early Ultrasound Exam". OB/GYN News. Retrieved on 2007-05-27. 
6. ^ Clark, Stephanie Brown. (2005). Jan Steen: The Doctor's Visit. Literature, Arts, and Medicine Database. Retrieved 2007-05-27.
   Lubsen-Brandsma, M.A. (1997). Jan Steen's fire pot; pregnancy test or gynecological therapeutic method in the 17th century?. Ned Tijdschr Geneeskd, 141(51), 2513–7. Retrieved 2006-05-24.
   "The Doctor's Visit." (n.d.). The Web Gallery of Art. Retrieved 2006-05-24.
7. ^ Speert, Harold (1973). Iconographia Gyniatrica. Philadelphia: F. A. Davis. ISBN 978-0803680708. 
8. ^ Weschler, Toni (2002). Taking Charge of Your Fertility, Revised Edition, New York: HarperCollins, p.374. ISBN 0-06-093764-5. 
9. ^ Ellington, Joanna (2004). Sperm Transport to the Fallopian Tubes. Frequently Asked Questions with Dr. E. INGfertility Inc. Retrieved on 2006-08-13.
10. ^ Phillips, Pat (2007). Early Pregnancy Tests. Pregnancy Test FAQ. Retrieved on 2007-03-04.