Listeria
Infection in Pregnancy
Listeriosis is
an infection caused by Listeria monocytogenes.Up to one in
twenty adults have this bacterium in their feces, so the infection is a
fecal-oral route, much like the feline-caused Toxoplasmosis, and is probably
everywhere. Foods contaminated with Listeria, like soft cheeses and
unpasteurized products and cold cuts, can cause outbreaks, but in pregnancy
it can have no symptoms at all or cause an illness that may be confused
with a urinary tract infection or with just a flu that is managed with
fluids and tylenol.
In pregnancy, this maternal
infection can also infect the baby:
-
If contracted early, it can cause miscarriage.
If the infection occurs later on, it can cause Intrauterine Growth Restriction
(IUGR).
Other infectious
causes for IUGR include viral infections like Rubella, Cytomegalovirus,
Hepatitis A and B, influenza, and chicken pox. Tuberculosis, a bacterial
infection, and syphilis (caused by an organism called a spirochete) also
cause IUGR.
-
In the third trimester, Listeria
can be a cause for premature labor, premature delivery, and ultimately
can cause neonatal sepsis, meningitis, and death--a baby-killer.
The meningitis in the baby can even develop after the first few weeks of
life.
In private practice it
is an infection that is easily missed. It is a fairly weakly infectious
bacterium, usually seeking out theimmuno-compromised, like persons with AIDS...or pregnancy.
It is felt that exposure to it usually will not
cause infection, because it is so common a germ.
The true frequency of infection
and infection affecting pregnancy is unknown for several reasons.
Few obstetricians get routine cultures on miscarriages, assuming correctly
that miscarriage is usually the result of genetic mishaps, especially in
the absence of maternal symptoms. Because it is not checked for scrupulously
and because it seems to be everywhere in contaminated products, the epidemiology
statistics are still quite a mess.
Listeria in pregnancy usually
appears as flulike, which can be scary when almost every pregnant woman
gets flu-like symptoms at some point in her pregnancy. Low grade
fever, headache, and muscle pain are common, but there may be no
symptoms at all. Less commonly there can be diarrhea and cramps.
The
mother may suffer minimally, but the baby's situation is life-threatening.
Delivery usually unloads the
largest amount of the infection from the mother's body, causing immediate
improvement. Treatment of the mother may or may not help the undelivered
baby. In the past, a combination of Ampicillin (a broad spectrum
penicillin) and Gentamycin (an antibiotic classified as an "aminglycoside")
has been used. But the onset of premature labor in a baby already
seen compromised will have an obstetrician weighing the risk vs. benefit
of delivery. Certainly delivery is indicated in the late third trimester
so that treatment can be attempted on the newborn. In cases of severe
prematurity, there is no "best" answer for a difficult question.
In the real world, obstetricians
don't obtain blood cultures and other tests for Listeriosis on every woman
with a low grade fever, headache, or muscle aches. They can't.
| A case study:
A pharmacist's
wife I had been caring for came in for a routine visit at about 37 weeks.
She claimed some vague change in fetal movement had occurred. The
ultrasound didn't show anything worrisome, but just to be ridiculously
(I thought) overcautious, I had her undergo a fetal non-stress test.
The test was somewhat reassuring, but not perfect, so I sent her to the
hospital for a contraction stress test. With each contraction induced,
there was a deceleration of the fetal heart rate. More alarmingly,
it was what is called a "late" deceleration, indicating that not only did
the baby not have a lot of reserve for stress, but also was reacting to
stress in a delayed way, indicative of fetal distress. Besides this
test indicating that the baby could not tolerate a labor, the patient's
Bishop's score was not favorable, so any labor would be a lengthy one at
that.
At C-section,
there was a lower than normal APGAR score, but it improved at 5 minutes
and the baby ultimately did fine. I obtained cultures on both sides
of the placenta and of the amniotic fluid at the time of surgery, and the
results grew out Listeria. Mom and Dad gave me a ceramic
angel to hang up in our non-stress test exam room, where I always think
about Listeria when things aren't quite right. |
