For years, doctors have routinely screened pregnant
women for infections which affect the outcome of the
pregnancy or cause birth defects in the baby. Gonorrhea
and chlamydia are checked for with cervical smears
and syphilis is assessed using a blood test. Each
of these STDs can cause a problem in the newborn with
eye infections and even congenital structural defects
for syphilis. Hepatitis and HIV are other viral diseases
that mainly are transmitted to the baby during birth
so it is useful to know if they are present so that
newborn infections can be prevented. There are other
infections in pregnancy, however, that are frequently
associated with preterm labor - bacterial vaginosis,
group B streptococcus, urinary tract infections, trichomonas
and mycoplasma hominis. Doctors are checking for these
infections much more frequently now because of the
serious impact that prematurity can make in a baby's
survival. Approximately 80% of women undergoing preterm
labor have one or more of these infections going on.
What signs and symptoms are present when
these perinatal infections are present?
Burning urination and urinary frequency are signs
of lower urinary tract infections. Vaginal discharge
may also be a sign of infection especially if the
discharge is any color other than clear or white or
if there is an odor present spontaneously or with
sexual relations. Many women are unaware that vaginal
bleeding during pregnancy is also associated with
vaginal infections.
In a study by French JI et al: Gestational bleeding,
bacterial vaginosis, and common reproductive tract
infections: Risk for preterm birth and benefit of
treatment. Obstet Gynecol 1999;93:715-24, the authors
found an 11% incidence of 1st trimester bleeding,
6.4% in the second trimester and 4.1% in the third
trimester. By analysis, each of the infections of
trichomonas, Chlamydia, and bacterial vaginosis, were
associated with bleeding problems; group B streptococcal
was not. In women with vaginal bleeding during pregnancy,
44% had bacterial vaginosis and 82% had positive cultures
for ureaplasma urealyticum. Antibiotic treatment of
infections when they were found antenatally resulted
in a 50% reduction in the rate of preterm labor.
I have heard that Group B strep can cause
death in newborn infants. Will my doctor check me
for it?
Group B strep is often associated with premature rupture
of the membranes (broken bag of waters). A newborn
can acquire group B Strep during labor and delivery
and rarely die from the blood born sepsis it causes.
Group B strep is extremely difficult to eradicate,
however, so that it is not recommended to treat in
early pregnancy because most infections come back.
Rather, it is recommended to screen women who have
had a previous pregnancy with a Group B strep infection,
a history of a stillborn or neonatal death, or premature
rupture of the membranes in the current pregnancy.
Some doctors will also screen women with vaginal and
rectal cultures for group B strep at 35-36 weeks of
pregnancy and treat those women who are positive during
labor and delivery. Penicillin or cephalosporin antibiotics
are the treatments of choice.
How bad is it to have urinary tract infections
in pregnancy?
Urinary tract infections lead to preterm labor as
well as increase the risk for infections that ascend
into the kidney, pyleonephritis, and may cause permanent
kidney damage. From 3-10% of women have urinary tract
infections in pregnancy and most of these are preceded
by bacteria in the urine without any symptoms (asymptomatic
bactiuria). Most screening tests in pregnancy are
designed pick up asymptomatic bactiuria and treat
it before it even becomes a UTI, much less a serious
pyleonephritis. If a woman does have a pyleonephritis
infection during pregnancy, she needs a kidney Xray
after delivery to look for congenital anomalies of
the urological tract. If the infection does not clear
with adequate treatment in pregnancy imaging studies
may need to be done during pregnancy to rule out any
renal abscesses that do not clear up.
Do other types of vaginal infections cause
harm to the baby?
Yeast vaginitis does not seem to cause a problem producing
preterm labor or an infection in the newborn. Trichomonas
is associated with bleeding and preterm labor as was
previously mentioned. A little heard of, but very
common infection is mycoplasma hominis, mycoplasma
genitalium and ureaplasma urealyticum. They can be
cultured so frequently from the vagina and cervix
that there is sometimes a question as to whether they
really cause a problem. It may have do do with the
amount of bacterial load rather than the presence
of them that is important. Erythromycin is the treatment
of choice for mycoplasma genitalium and ureaplasma
urealyticum which are probably the infections to be
concerned about. Not enough is known about these and
doctors do not routinely culture for them. So unless
there is a past history of preterm labor or delivery,
it is uncertain to what degree these are clinically
important.
What if I have HPV - venereal warts? Will
my baby get it?
You cannot diagnose human papilloma virus infection
by Pap smear. You can suspect it, but the diagnosis
is by DNA sequence subtyping of cervicovaginal smears.
The incidence of positivity is 20-30% in all women
delivering infants but if one considers historical
infections and earlier in pregnancy testing, the overall
incidence in the population is about 75%. Studies
have shown anywhere from a 3% to a 37% transmission
rate to the infant. There is less colonization of
newborns when delivery is by C-Section (27%) than
by vaginal delivery (51%), but the incidence of a
newborn getting an active infection or a bad disease
like laryngeal cord papillomas is extremely small.
Most doctors consider the infant culture data evidence
of contamination when the baby is delivered rather
than infection since the positivity of the infant
decreases over several months.
There are no current recommendations to alter delivery
based on having signs or laboratory studies showing
and HPV infection.
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