for several weeks to several months, depending on
the gestational age at birth. About 10 percent of
babies in the United States are born prematurely.
The most common causes of premature birth are
multiple PREGNANCY and PREECLAMPSIA. Women
who have DIABETES, HYPERTENSION(high BLOOD PRES-
SURE), and chronic kidney disease have increased
risk for premature delivery.
See also ABORTION; NEONATAL JAUNDICE; STILLBIRTH.
premenstrual syndrome (PMS) A constellation
of symptoms that occurs in a regular pattern
aligned with a woman’s MENSTRUAL CYCLE. Doctors
believe PMS results from the hormonal shift in the
balance between ESTROGENSand PROGESTERONEthat
follows involution of the corpus luteum. This shift
sets in motion the events that produce MENSTRUA-
TION. PMS tends to begin during the last half of the
luteal phase and continue to the onset of men-
strual bleeding, typically spanning five to seven
days. As many as 85 percent of women experience
some symptoms of PMS; about 10 percent experi-
ence symptoms significant enough to interfere
with daily activities. Some doctors call debilitating
symptoms premenstrual dysphoric disorder
(PMDD).
Symptoms and Diagnostic PathThe symptoms of PMS may vary from month to
month in a woman and also vary widely among
women. Common PMS symptoms include
- irritability, extreme emotions, and mood swings
- MASTALGIA(painful breasts)
- confusion, forgetfulness, and difficulty concen-
trating - abdominal cramping and bloating
- low back ache or PAIN
- fluid retention and swelling of the hands,
ankles, and feet - weight gain (as much as two to four pounds)
The diagnostic path begins with a comprehen-
sive medical examination, including PELVIC EXAMI-
NATION. The doctor may ask the woman to keep a
daily diary of her symptoms over three to six
months, which helps to establish a clear pattern of
symptoms and their severity. The doctor may
request BLOODtests and abdominal ULTRASOUNDto
rule out hormonal imbalances, ovarian conditions,
and other possible causes for symptoms.Treatment Options and Outlook
Mild to moderate PMS often improves with
lifestyle modifications, including sufficient sleep,
nutritious EATING HABITS, daily physical exercise,
MEDITATION or other relaxation methods, and
reduced CAFFEINE consumption (though some
women find the diuretic and mild stimulant
effects of caffeine helpful). BIOFEEDBACK and
ACUPUNCTUREare also often effective. Supplemen-
tation with B vitamins, vitamin E, and calcium
appear to reduce PMS symptoms, though it may
take several months for the effect to become
apparent. Evening primrose oil, SOYand other PHY-
TOESTROGENS, DONG QUAI, and BLACK COHOSH are
among the herbal remedies that may relieve PMS
symptoms. Over-the-counter (OTC) NONSTEROIDAL
ANTI-INFLAMMATORY DRUGS(NSAIDS) relieve HEADACHE
and mastitis, and may reduce other symptoms
because of their actions to suppress the release of
PROSTAGLANDINS(chemicals that increase the sensi-
tivity of nerves to pain signals).
Selective serotonin reuptake inhibitors (SSRIs),
a class of ANTIDEPRESSANT MEDICATIONS, are effective
in relieving moderate to severe PMS symptoms
and are the current standard of care for PMS as
well as PMDD. Researchers believe SSRIs work so
well because they influence the neurohormonal
interactions that take place in the BRAIN. Though
some women find their symptoms improve with
oral contraceptives (birth control pills), recent
research suggests progesterone (which appears in
the synthetic form progestin in many oral contra-
ceptive formulas) is a key factor in causing PMS.
Current clinical guidelines recommend oral con-
traceptives as treatment for PMS only when the
woman also desires to take them as a means of
preventing PREGNANCY.Risk Factors and Preventive Measures
PMS occurs only in menstruating women. How-
ever, though PMS is very common not all men-
struating women experience it. Some research
suggests that women may metabolize proges-
terone differently, accounting for differences in its
effects during the menstrual cycle. Lifestyle meas-premenstrual syndrome (PMS) 325