Medical Dictionary Definitions A-Z List
Medical Dictionary Definitions A - Z - «P»:
Premature ventricular beat
Premature ventricular beat: See: Extrasystole.
Premature ventricular contraction
Premature ventricular contraction: PVC. A contraction
of the lower chambers of the heart, the ventricles, which occur earlier than usual,
because of abnormal electrical activity of the ventricles. The premature contraction is
followed by a pause, as the heart electrical system "resets" its...
Prematurity: Historically, the definition of prematurity was 2500
grams (about 5 1/2 pounds) or less at birth. The current World Health Organization
definition of prematurity is a baby born before 37 weeks of gestation, counting from the
first day of the Last Menstrual Period (LMP). ...
Premenstrual: Just before the start of menstruation. As in a premenstrual headache....
Premenstrual dysphoric disorder
Premenstrual dysphoric disorder (PMDD): a severe form of the premenstrual syndrome (PMS). Both premenstrual syndrome and premenstrual dysphoric disorder are characterized by unpleasant physical and psychological symptoms (such as fatigue, mood changes, irritability, and abdominal bloating) that occu...
Premenstrual syndrome: A combination of physical and mood disturbances that occur in the last half of a woman's menstrual cycle after ovulation and normally end with the onset of the menstrual flow. Physical features of the premenstrual syndrome (PMS) include breast tenderness and bloating. Psycholo...
Premie: Short and slangy for a premature baby. A preterm infant. Also often spelled (for obscure reasons) preemie.
Prenatal: Occurring or existing before birth.
Prenatal care is the regular health care women should
receive during pregnancy from an obstetrician or midwife.
Prenatal development is the growth and development of a single-celled zygote formed by the combination of a sperm and an egg into a baby.
Prenatal care: During pregnancy, women should
receive regular health care from an obstetrician or
midwife. Services needed include dietary and lifestyle
advice, weighing to ensure proper weight gain, and
examination for problems of pregnancy such as edema and
preeclampsia (toxemia). In cases wh...
Prenatal development: The process of growth and
development within the womb, in which a single-cell zygote
(the cell formed by the combination of a sperm and an egg)
becomes an embryo, a fetus, and then a baby. The first two
weeks of development are concerned with simple cell
Prenatal diagnosis: Diagnosis before birth.
Methods for prenatal diagnosis include ultrasound of the
uterus, placenta, and/or developing fetus; chorionic villus
sampling (CVS) to obtain tissue for chromosome or
biochemical analysis; and amniocentesis to obtain amniotic
fluid for the analysis of...
Prenatal radiation exposure
Prenatal radiation exposure: The exposure of an unborn baby to radiation. Radiation exposure of the fetus can occur when the mother's abdomen is exposed to radiation from outside her body as, for example, by diagnostic X-rays. A pregnant woman may also be exposed to radiation by swallowing or breath...
Prenatal surgery: The surgical treatment of the fetus before birth. Also called antenatal surgery or, most often, fetal surgery.
Fetal surgery is done when the fetus is not expected to live long enough to make it through to delivery or to live long after birth unless fetal surgery is performed. For...
Preop: Short for preoperative, before surgery. The opposite of preop is postop....
Preoperative: Before surgery. As opposed to postoperative, after surgery....