HDCN Ask the Professor: Pregnancy in a CAPD patient
I am an obstetrician-gynecologist, and I have a patient with CAPD who is 19
weeks pregnant. She is 23 years old and this is her second pregnancy. Last April,
had a spontaneous abortion of twins at 16 weeks gestation.
Her blood pressure is
well controlled by Aldomet (alpha methyldopa) and she is receiving
erythropoietin. I am looking
for case histories, articles or for any personal experience you might have
with CAPD in pregnancy.
Nicole Racette, MD (Vancouver, Canada)
Response by Dr. Susan Hou, Associate Professor of Medicine, Rush-Presbyterian
St. Luke's Medical Center, Chicago, IL:
Pregnancy is infrequent in women receiving chronic dialysis and the outcome is generally felt to be
poor. There have been case reports of women receiving peritoneal dialysis which suggest that
pregnancy may have a better outcome
with this ESRD treatment modality. It is postulated that peritoneal dialysis may allow for a more
constant intrauterine metabolic environment and fewer rapid changes in volume, with a beneficial
effect for the fetus. Many questions about peritoneal dialysis during pregnancy remain:
Should a woman who starts dialysis during pregnancy be started on peritoneal dialysis?
Should a pregnant hemodialysis patient be switched to peritoneal dialysis?
Should changes be made in the dialysis regimen?
Will the catheter function normally?
What effect will peritonitis have on the baby and how should it be treated?
Isn't the abdomen going to get a little crowded with the catheter, the dialysate and the baby?
Frequency of conception in peritoneal dialysis patients
There are approximately 13,000 women under the age of 44 receiving chronic dialysis in the United
States. Twenty-five percent of these are treated with peritoneal dialysis. A survey of 35% of
women of childbearing age over a three year period revealed 9 pregnancies, or 0.25 % per year. In
contrast, hemodialysis patients become pregnant more than twice as often. The reasons for the
differences in the frequency of conception are not understood.
CAPD regimen during pregnancy
A widely practiced although unproven practice in the care of the pregnant dialysis patients is to
increase the total amount of dialysis delivered. There is no commonly accepted target KT/V for a
pregnant woman, but the goal is to achieve a higher KT/V than is accepted as adequate dialysis in a
non pregnant patient. With hemodialysis, this goal is achieved by increasing the frequency of
dialysis to as often as six days a week. With peritoneal dialysis, the achievement of a higher than
usual KT/V requires an increased number of exchanges. It is sometimes necessary to combine several
daytime exchanges with the use of a cycler at night. Increasing the amount of dialysis delivered is
made more difficult in late pregnancy because exchange volumes have to be decreased because of
Catheter placement during pregnancy
A recently established American Registry for Pregnancy in Dialysis
Patients has recorded 13 instances where peritoneal dialysis catheters were placed during
pregnancy between 4 and 29 weeks gestation. Only one instance of a leak and two instances of
failure to drain were noted. Two patients were switched from peritoneal to hemodialysis during
pregnancy for catheter problems. One was because of failure to drain. In a second instance a
woman who conceived after starting CAPD had serious bleeding resulting from laceration of a uterine
vein by a peritoneal dialysis catheter.
One concern about the use of peritoneal dialysis during pregnancy is what effect peritonitis might
have on the pregnancy. The information on peritonitis is limited. There are three published
reports of peritonitis reported in CAPD patients. Two were followed by premature labor with one
premature birth and one stillbirth. Because of the connection between fallopian tubes and the
peritoneum, there is a risk that any pregnancy associated infections may lead to peritonitis. If
peritonitis becomes a common problem in pregnant CAPD patients, its contribution to premature labor
may be substantial.
When peritoneal dialysis was first used in pregnant women, it was hoped that obstetric bleeding
problems might be reduced with a modality which did not require the use of heparin. However,
bleeding problems continue to occur. Bloody dialysate, which is rarely a sign of a serious problem
in a non pregnant patient, may indicate abruptio placentae or impending abortion. A pregnant woman
with bloody dialysate should be hospitalized for observation and should have an ultrasound to look
for placental separation.
The most common life threatening problem encountered in pregnant CAPD patients is hypertension.
Eighty percent of pregnant women treated with CAPD develop hypertension during pregnancy and 40%
suffer diastolic blood pressures greater than 110 mm/hg.
During normal pregnancy, red cell production is increased as is plasma volume. In dialysis
patients, intravascular volume increases but hematocrit usually drops. Erythropoietin appears to be
safe during pregnancy. It does not cross the placenta and does not appear to make hypertension more
difficult to control. However, the dose must be increased some times more than twofold to maintain
the prepregnancy hematocrit. The tendency toward iron deficiency is aggravated by pregnancy.
Fifty percent of pregnancies in CAPD patients reported to the American Registry resulted in
surviving infants. The success rate for pregnancy is 43% in hemodialysis patients but the
difference between the two modalities is not statistically significant. There is not enough
evidence of better outcome in CAPD patients to warrant changing dialysis modalities during
pregnancy. Most infants are born prematurely.
In summary, peritoneal dialysis patients become pregnant less frequently than hemodialysis patients,
but when pregnancy occurs, the outcome is as good or better than in hemodialysis patients. The use
of peritoneal dialysis does not avoid the problems of hypertension, bleeding, and premature birth
that plague pregnancies in hemodialysis patients. Peritonitis and catheter problems are unique to
peritoneal dialysis. Pregnancy in any dialysis patient is a high risk situation and the specific
role of peritoneal dialysis in management of such pregnancies is a subject of ongoing investigation.