Glossary P
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Pap smear (Papanicolaou smear)

A screening method for cervical cancer named after George Papanicolaou (1883-1962), the American cytologist who developed this method. Using an Ayers spatula (and sometimes a brush or a plastic-fronded broom.) cells are taken from the endocervical canal and transitional zone of the cervix and smeared thinly on a glass microscope slide. The slide is the sprayed or immersed in a fixative to be examined later for abnormalities in the laboratory.

Para, Parity

The number of completed pregnancies beyond 20 weeks gestation (whether viable or nonviable). The number of fetuses delivered does not determine the parity. For example a woman who has been pregnant once and delivered twins at 38 weeks would be noted as Gravid 1 Para 1.

1. Cunningham FG. ed Williams Obstetrics, 22nd ed.,  New York: McGraw-Hill.2005
2. Mark Morgan and Sam Siddighi. NMS Obstetrics and Gynecology (National Medical Series for Independent Study).2004 p 45

Parenteral Nutrition (Total parenteral nutrition, partial parenteral nutrition, Hyperalimentation)

Substances necessary for life and growth such as carbohydrate, proteins, and fat fed directly into a vein. Usually given to people who are not able to take food by mouth .

Patent Ductus Arteriosus (PDA)

Failure of the blood vessel (called the ductus arteriosus) to close after birth. The ductus arteriosus  is a normal structure in the fetus that diverts blood from the fetal lungs by connecting the pulmonary artery directly to the ascending aorta. 


A physician who has completed specialty  training in the development, care and diseases of children.

Pelvic inflammatory disease (PID, acute salpingitis)

A general term for inflammation caused by infection of the upper genital tract not associated with pregnancy or pelvic operations.

Percent transferrin saturation (TSAT)

Transferrin saturation (%) = {serum iron concentration (ug/dL)/TIBC (ug/dL)} x 100 (Serum iron/TIBC) X 100%

Percutaneous umbilical blood sampling (PUBS)

A procedure in which a needle is inserted into the uterus and into the umbilical cord of the fetus at the base of the placenta. A sample of fetal blood is then withdrawn.


Around the time of birth. As defined by the World Health Organization (WHO) ICD-10 the perinatal period is begins at " 22 completed weeks (154 days) of gestation (the time when birthweight is normally 500 grams) and ends seven completed days after birth".


A physician who has completed specialty training in obstetrics and gynecology and additional subspecialty training in high risk pregnancy and disorders of the fetus. Also called a maternal-fetal medicine specialist.

Perinatal mortality rate (PNMR)

The number of perinatal deaths (fetal deaths at  22 weeks' or more gestation and neonatal deaths to 7 completed days after birth) per 1,000 total births. It is usually reported on an annual basis.

Pfannenstiel's incision (Bikini incision)

A horizontal cut made through the skin just above the joint of the pubic bones. The incision is carried down through the underlying fat and through the fibrous tissue that surrounds the rectus muscles of the abdomen (the anterior rectus fascia ).

The incision was developed by the German gynecologist Hermann Johannes Pfannenstiel and provides an excellent cosmetic result. However, the incision does not provide good access to the upper abdomen.

Placenta (Afterbirth)

A disk-shaped organ that develops during pregnancy. The placenta is attached to the uterus on one side by its large flat surface and to the fetus by the umbilical cord on its other side. The placenta exchanges nutrients, wastes, and gases between the blood of the mother and fetus as well as producing numerous hormones. Normally the placenta is delivered after the birth of the infant.

Placenta Accreta, Increta, Percreta

Abnormal penetration of the placenta beyond the lining of the uterus to varying depths.

  • Placenta accreta. The placenta adheres directly to the myometrium (muscular wall of the uterus)
  • Placenta increta. The placenta grows into the myometrium.
  • Placenta percreta. The placenta grows completely through the myometrium.

The abnormally firm attachment of the placenta to the uterus does not allow the placenta to separate  from the uterine wall spontaneously after delivery of the fetus. Attempts to manually remove the placenta may sometimes cause massive bleeding. In addition placenta percreta may cause damage to nearby organs such as the bladder.

About two thirds of the patients with placenta previa/placenta accreta will require cesarean hysterectomy at delivery. However, in the stable patient attempts to avoid hysterectomy and preserve fertility by various means (including leaving the placenta in place) have been successful. Placement of catheters for embolization of pelvic vessels prior to elective delivery has also been described.

Prior cesarean delivery or other uterine surgery and placenta previa are the factors most often associated with placenta accreta, increta, and percreta. In patients with placenta previa the incidence of placenta accreta appears to correlate with the number of previous cesarean sections.

Placenta accreta may sometimes be diagnosed before delivery by sonogram. Findings of accreta on ultrasound include:

  • A thin and distorted uterine serosa-bladder interface.
  • Multiple placental lakes (placental vascular lacunae) that give the placenta a "Swiss cheese" or "moth eaten" appearance.
  • Loss of the  normal hypoechic zone "clear space" beneath the placenta.
  • Large blood vessels may be seen to invade the bladder wall with percreta.

Placental insufficiency

Failure or inability of the placenta  to normally exchange nutrients, wastes, and gases between the blood of the mother and fetus. The typical pathological finding in placental insufficiency is obliteration of the small muscular arteries in the tertiary stem villi of the placenta which is often associated with an abnormal uterine artery waveform on pulsed-wave Doppler ultrasound.

See also: Umbilical Artery (UA) Impedance Indices

1. Giles WB, et al .,Fetal umbilical artery flow velocity waveforms and placental resistance: pathological correlation. Br J Obstet Gynaecol. 1985 Jan;92(1):31-8. PMID: 3966988
2. Kingdom JC, Burrell SJ, Kaufmann P. Pathology and clinical implications of abnormal umbilical artery Doppler waveforms. Ultrasound Obstet Gynecol. Apr 1997;9(4):271-86PMID: 9168580
3. Baschat AA, Weiner CP.Umbilical artery doppler screening for detection of the small fetus in need of antepartum surveillance. Am J Obstet Gynecol. 2000 Jan;182(1 Pt 1):154-8.PMID: 10649171


Placenta Previa

A condition in which the placenta (including the marginal veins) partially or completely covers the opening of the cervix (cervical os).

Placental lakes (placental vascular lacunae, placental caverns, placental venous lakes, placental sonolucencies)

Placental lakes are enlarged spaces in the placenta filled with maternal blood called also called intervillous vascular spaces.

Placental villi

Finger-like projections of the placenta that contain fetal blood vessels. The villi are surrounded by spaces containing maternal blood (intervillous space).

Pleural effusion

Ponderal index (PI)

A ratio of body weight to length used as an indicator of asymmetric fetal growth status . The Ponderal index makes the assumption that the length is unaffected by changes in nutritional status .

Expressed as:
 PI = [birth weight (g) x 100] [birth length (cm)] 3

Normal range: 2.32 to 2.85 g/cm3

Gozal D, et al. Anthropometric measurements in a newborn population in west Africa: a reliable and simple tool for the identification of infants at risk for early postnatal morbidity.
J Pediatr. 1991;118(5):800-5.  PMID: 2019937

Positive end expiratory pressure (PEEP)

The amount of pressure above atmospheric pressure in the airway at the end of the expiratory cycle. PEEP prevents improves exchange of oxygen and carbon dioxide by preventing collapse of the small air sacs (alveoli) in the lungs.



Following birth.

Postpartum blues

A common (up to 70% of women) self limiting condition occurring within a few days of delivery. Characterized by mood lability, weeping, depression, fatigue, anxiety, confusion, difficulty concentrating, and depersonalization.

Postpartum depression

A condition (~ 10%) occurring within days to weeks following delivery and lasting more than 2 weeks. Characterized by  vegetative signs of depression, tearfulness, anxiety, loss of interest in normal activities, guilt, inadequacy in coping with the infant duration, thoughts of suicide. Risk factors for developing postpartum depression include previous depression and unsupportive home environment Typically requires treatment for up to 6 months with antidepressants. Psychiatric consultation may be helpful.

Postpartum psychosis

Uncommon condition occurring within a few days and up to 4 weeks after delivery. Characterized by auditory hallucinations, delusions, euphoria, grandiosity, hyperactivity, and inappropriate affect. There is a high risk of infanticide and a high chance of developing psychosis in the future. Risk factors for developing postpartum psychosis include a history of psychosis. Treatment usually requires hospitalization.


A condition of pregnancy characterized by high blood pressure and protein in the urine. Approximately 5% to 7% of all pregnancies are complicated by preeclampsia.  Women are more likely to develop preeclampsia during their first pregnancy, if they are over the age of 40,or  if they have diabetes, a multiple gestation (twins), or a family history of preeclampsia. Women with antiphospholipid syndrome, chronic hypertension, and chronic renal disease are ten times more likely to develop preeclampsia than women without these conditions.

Preeclampsia is diagnosed if the following criteria are met:

A systolic BP of at least 140 mm Hg  AND/OR a diastolic BP of at least 90 mm Hg on at least two occasions at least 6 hours apart after the 20th week of gestation in women who did not have high blood pressure before 20 week's gestation.


Protein in the urine (proteinuria). 300 mg or more per 24-hour period or at least 1+ on dipstick in at least two random urine samples collected at least 6 hours apart.

Women may have no symptoms, or they may experience unremitting headache, visual problems, epigastric pain (like severe heartburn), cough, and rapid weight gain due to water retention. Women with preeclampsia have constricted peripheral blood vessels (vasospasm) and intravascular volume depletion.

The course of the disease is difficult to predict. Preeclampsia tends to be milder when it occurs late in pregnancy, but can progress at anytime to a severe form with the development of very high blood pressure and seizures (eclampsia). Severe preeclampsia can also cause fetal growth restriction, placental abruption, pulmonary edema, disseminated intravascular coagulation, and maternal stroke.

Central to the pathophysiology of preeclampsia is vasospasm accompanied by intravascular volume depletion. The cause of preeclampsia is uncertain but appears to involve failure of the spiral arteries of the placenta to completely dilate. In addition the spiral arteries continue to be responsive to substances that promote constriction of blood vessels. Altered levels of antiangiogenic factors (fms-like tyrosine kinase and endoglin) and the proangiogenic protein placental growth factor appear to be involved.

The only effective cure for preeclampsia is delivery. Magnesium sulfate is usually given around the time of delivery to prevent seizures.


1. ACOG Technical Bulletin Number 219 Preeclampsia-- January 1996
2. ACOG practice bulletin. Diagnosis and management of preeclampsia and eclampsia. Number 33, January 2002. Obstet Gynecol. 2002 Jan;99(1):159-67.PUBMED
3.Soluble endoglin and other circulating antiangiogenic factors in preeclampsia.N Engl J Med. 2006 Sep 7;355(10):992-1005. Erratum in: N Engl J Med. 2006 Oct 26;355(17):1840. PUBMED
.Report of the National High Blood Pressure Education Program Working Group on High Blood Pressure in Pregnancy. Am J Obstet Gynecol. 2000 Jul;183(1):S1-S22.PUBMED


Less than 37 completed weeks' (less than 259 days) of gestation

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