Encyclopedia of Health and Medicine

prostate cancer 327
the prospective due date. Weight, blood pressure,
and urine sample for glucose and protein remain
staples of prenatal visits in the second trimester.
Around the 18th week the health-care provider
offers a set of screening blood tests, the triple
screen or the quad screen. These tests measure
certain hormones and proteins in the woman’s
blood that may suggest neural tube defects such as
SPINA BIFIDA and chromosomal disorders such as
DOWN SYNDROME. The results of these tests are specific
to the gestational age so the provider will be
as certain as possible about the due date before
conducting them.
It is important for the woman, her partner, and
the provider to discuss the implications of positive
results from screening tests, and for the woman
and her partner to consider what actions they
might take. The provider typically recommends
amniocentesis to further evaluate positive triple
screen or quad screen results. The provider may
recommend abdominal ultrasound around the
20th week if the due date is questionable or if
there is reason to suspect abnormalities in fetal
development. At the end of the second trimester
the provider typically requests a glucose challenge
test to check for GESTATIONAL DIABETES as well as
blood tests to check for anemia.
MATERNAL SCREENING BLOOD TESTS
Triple Screen
ALPHA FETOPROTEIN (AFP)
beta human chorionic gonadotropin (beta-HCG)
unconjugated estriol (uE3)
Quad Screen
AFP
beta-HCG
uE3
pregnancy-associated plasma protein A (PAPP-A)
Prenatal Care: Third Trimester
Routine prenatal care visits shift to every two
weeks between 28 and 36 weeks and weekly from
36 weeks until delivery. The health-care provider
continues to check weight, urine, and blood pressure.
Early in the third trimester the provider discusses
the potential for delivery by CESAREAN
SECTION if the fetus is in a breech position or there
are other circumstances that might increase the
risk to the fetus or the woman with a vaginal
delivery.
At the 34th or 35th week the provider cultures
swabbed samples from the VAGINA and rectum for
group B streptococcus (GBS) BACTERIA, which
some women harbor without harm to themselves
but that can cause life-threatening INFECTION in the
newborn. Women who test positive for GBS
receive ANTIBIOTIC MEDICATIONS when they go into
labor. The provider also monitors the status of
GENITAL HERPEs, when this STD is present, to be
prepared for cesarean section should an outbreak
occur near the anticipated time of delivery.
See also CONGENITAL ANOMALY; FAMILY PLANNING;
FETAL ALCOHOL SYNDROME; PREVENTIVE HEALTH CARE
AND IMMUNIZATIONS.
priapism A condition in which a man’s PENIS
remains erect for longer than four hours. Priapism
is involuntary (not a function of sexual stimulation),
painful, and requires immediate medical
attention to prevent permanent damage to the
penis and preserve sexual function. Priapism is
most often a SIDE EFFECT of medication, notably
medications to treat ERECTILE DYSFUNCTION and the
antidepressant medication trazodone. It also may
occur as a complication of SICKLE CELL DISEASE, GENI-
TAL TRAUMA, and PROSTATE CANCER. Treatment may
include evacuation of BLOOD from the corpora cavernosa,
the tubular channels within the penis that
fill with blood to establish an erection, via needle
and syringe or intravenous catheter. The doctor
may also inject the penis with vasoconstrictor
medications. If medical interventions fail, surgery
may be necessary to implant a shunt that allows
blood to drain from the penis.
See also ANTIDEPRESSANT MEDICATIONS; PARAPHIMO-
SIS; PEYRONIE’S DISEASE.
prostate cancer A malignant (cancerous) tumor
that arises from the glandular tissue of the
PROSTATE GLAND, a walnut-size structure that encircles
a man’s URETHRA at the base of the BLADDER.
Prostate cancer is one of the HORMONE-DRIVEN CAN-
CERS that appears to have some genetic foundations
as it tends to run in families. Prostate cancer
also strongly correlates to increased age; it is rare
among men under age 50 and affects more than
half of men over age 70.