The beginning of pregnancy may be detected either based on symptoms by the woman herself, or by using pregnancy tests. However, an important condition with serious health implications that is quite common is the denial of pregnancy by the pregnant woman. About one in 475 denials will last until around the 20th week of pregnancy. The proportion of cases of denial, persisting until delivery is about 1 in 2500.[53] Conversely, some non-pregnant women have a very strong belief that they are pregnant along with some of the physical changes. This condition is known as a false pregnancy.[54]
Most pregnant women experience a number of symptoms,[55] which can signify pregnancy. A number of early medical signs are associated with pregnancy.[56][57] These signs include:
the presence of human chorionic gonadotropin (hCG) in the blood and urine&missed menstrual period&implantation bleeding that occurs at implantation of the embryo in the uterus during the third or fourth week after last menstrual period&increased basal body temperature sustained for over 2 weeks after ovulation&Chadwick's sign (darkening of the cervix, vagina, and vulva)&Goodell's sign (softening of the vaginal portion of the cervix)&Hegar's sign (softening of the uterus isthmus)&Pigmentation of the linea alba – linea nigra, (darkening of the skin in a midline of the abdomen, caused by hyperpigmentation resulting from hormonal changes, usually appearing around the middle of pregnancy).[56][57]&Darkening of the nipples and areolas due to an increase in hormones.[58
Pregnancy detection can be accomplished using one or more various pregnancy tests,[59] which detect hormones generated by the newly formed placenta, serving as biomarkers of pregnancy.[60] Blood and urine tests can detect pregnancy 12 days after implantation.[61] Blood pregnancy tests are more sensitive than urine tests (giving fewer false negatives).[62] Home pregnancy tests are urine tests, and normally detect a pregnancy 12 to 15 days after fertilization.[63] A quantitative blood test can determine approximately the date the embryo was conceived because HCG doubles every 36 to 48 hours.[42] A single test of progesterone levels can also help determine how likely a fetus will survive in those with a threatened miscarriage (bleeding in early pregnancy).[64]
Obstetric ultrasonography can detect fetal abnormalities, detect multiple pregnancies, and improve gestational dating at 24 weeks.[65] The resultant estimated gestational age and due date of the fetus are slightly more accurate than methods based on last menstrual period.[66] Ultrasound is used to measure the nuchal fold in order to screen for Downs syndrome.[67]
The symptoms and discomforts of pregnancy are those presentations and conditions that result from pregnancy but do not significantly interfere with activities of daily living or pose a threat to the health of the mother or baby. This is in contrast to pregnancy complications. Sometimes a symptom that is considered a discomfort can be considered a complication when it is more severe. For example, nausea (morning sickness) can be a discomfort, but if, in combination with significant vomiting it causes a water-electrolyte imbalance, it is a complication known as hyperemesis gravidarum.
Common symptoms and discomforts of pregnancy include:
Tiredness.&Constipation&Pelvic girdle pain&Back pain&Braxton Hicks contractions. Occasional, irregular, and often painless contractions that occur several times per day.&Edema (swelling). Common complaint in advancing pregnancy. Caused by compression of the inferior vena cava and pelvic veins by the uterus leads to increased hydrostatic pressure in lower extremities.&Increased urinary frequency. A common complaint, caused by increased intravascular volume, elevated glomerular filtration rate, and compression of the bladder by the expanding uterus.&Urinary tract infection[22]&Varicose veins. Common complaint caused by relaxation of the venous smooth muscle and increased intravascular pressure.&Haemorrhoids (piles). Swollen veins at or inside the anal area. Caused by impaired venous return, straining associated with constipation, or increased intra-abdominal pressure in later pregnancy.[23]&Regurgitation, heartburn, and nausea.&Stretch marks&Breast tenderness is common during the first trimester, and is more common in women who are pregnant at a young age.[24
In addition, pregnancy may result in pregnancy complication such as deep vein thrombosis or worsening of an intercurrent disease in pregnancy.