Complications of Late Pregnancy
(Editors’ note: In the absence of qualified obstetrician/gynecologists,
surgeons in low-income countries are obliged to treat the surgical complications
of pregnancy and the female genital tract. It has been estimated that, in the
district hospital, these conditions may comprise at least 40% of the workload.(1)
For this reason Surgery in Africa will continue to post reviews on these important
and relevant topics.
(1) Lavy C, Tindall A, Steinlechner C, Mkandawire N, Chimangeni S.
Surgery in Malawi - a national survey of activity in rural and urban hospitals.
Annals of the Royal College of Surgeons of England 89(7):722-4, 2007.
http://simplelink.library.utoronto.ca.myaccess.library.utoronto.ca/url.cfm/42452)
1.0 Complications of Late Pregnancy
The purpose of this review is to address two common complications of late pregnancy,
abnormal vaginal bleeding and abnormally high blood pressure. The possible causes
of bleeding will be discussed and a review of hypertensive disorders of pregnancy
will be presented.
The initial management of significant bleeding in late pregnancy is similar
no matter what the cause of the bleeding may be. An initial survey should attempt
to estimate the amount of blood loss, although this may be difficult due to
concealed hemorrhage. Quick attention to the presenting vital signs looking
for hypotension, tachycardia, confusion, or breathlessness can alert the clinician
to hemodynamic instability. In cases of hemodynamic instability immediate intravenous
access, fluid resuscitation, and availability of blood products is necessary.
Baseline laboratory tests include hematocrit or hemoglobin, blood type, platelet
count, fibrinogen level, and coagulation studies. An assessment of the fetal
condition through auscultation of fetal heart tones or continuous fetal monitoring
should be done as soon as possible. (1)
2.0 Placental Abruption
2.1 Introduction
Placental abruption is defined as premature separation of a placenta that is
normally located in the fundus of the uterus. Abruption may be referred to as
“revealed” or “concealed.” When blood tracks between
the membranes and the decidua and escapes through the cervix into the vagina
the bleeding from the abruption is revealed. A “concealed” abruption
occurs when blood accumulates behind the placenta, and there is no obvious external
bleeding. A total placental abruption results in fetal death as all blood supply
to the placenta is lost. A partial abruption, with only a portion of the placenta
detached from the uterine wall, results in various degrees of fetal compromise.
(2)
Types of Placental Abruption – A- Revealed, B-Concealed
The management of abruption should be individualized on a case-by-case basis
depending on the severity of the abruption and the gestational age at which
it occurs. When abruption occurs at or near term and the fetal and maternal
status are good, the goal of a vaginal delivery can be pursued. In the presence
of fetal or maternal compromise, a prompt cesarean is often indicated. (2)
The incidence of placental abruption is 0.5% to 1.0% and seems to be increasing.
This condition is a leading cause of perinatal mortality and accounts for 10
to 15% of all perinatal deaths. (4)
2.2 Clinical Importance
Placental abruption has a wide range of clinical significance. A small area
of abruption may have minimal bleeding and little or no consequences to the
fetus or the mother. A massive abruption may cause fetal death in utero and
severe maternal morbidity. The danger to the mother is based mainly on the severity
of the abruption. The risk to the fetus is based both on the severity of the
abruption and the gestational age at which the abruption occurs. (2)
2.3 Risk Factors
Major risk factors for placental abruption include cocaine and drug use, multiple
gestation, chronic hypertension, mild and severe preeclampsia, cigarette smoking,
and premature rupture of membranes. Other lesser risk factors are maternal trauma,
thrombophilias, hydramnios, advanced maternal age, and intrauterine infections.
(3)
2.4 Pathophysiology
In many cases of placental abruption the precise pathophysiology is unknown.
Hemorrhage at the decidual-placental interface causes the abruption. (4)
Abruption, which occurs when there is a sudden uterine decompression resulting
from rupture of the membranes with hydramnios, or after delivery of a first
twin, may be caused by shearing forces. (1) In the majority
of cases, it seems that abruption may be the consequence of a long-standing
process that probably dates back to the first trimester. (2)
Acute separation of the placenta may deprive the fetus of oxygen and nourishment,
with the fetus dying. If the coagulation cascade is activated with consumption
of coagulation factors, disseminated intravascular coagulopathy (DIC) may ensue.
The risk is highest when there is a large placental detachment as to cause fetal
death. Continuing hemorrhage associated with DIC may lead to further consumption
of coagulation factors, setting off a vicious circle. Bleeding into the uterine
myometrium can lead to a beefy boggy uterus, called a Couvelaire uterus. (5)
2.5 Clinical Presentation
The classical presentation of abruption is vaginal bleeding accompanied by abdominal
pain. A severe abruption may occur with neither or just one of these signs.
The amount of vaginal bleeding correlates poorly with the degree of abruption,
because of the possibility of concealed bleeding. There is a positive correlation
between the extent of placental separation and the risk of stillbirth, with
stillbirth occurring in most cases in which there is greater than 50% placental
separation. (1) Typically, the uterus is tense and tender.
Backache may be the only symptom. (4)
2.6 Diagnosis
The diagnosis of abruption is a clinical one and should be suspected in women
who present with vaginal bleeding or abdominal pain or both, a history of trauma,
and those who present in otherwise unexplained preterm labor. Common symptoms
include vaginal bleeding, uterine pain, a tetanic contraction of the uterus,
and fetal heart rate abnormalities, including a sinusoidal pattern with continuous
fetal heart rate monitoring. (4) The ultrasonographic appearance
of abruption depends on the size and location of the bleed, as well as the duration
between the abruption and the time of the ultrasound. In cases of acute revealed
abruption the ultrasound may show no abnormalities. Ultrasonography will fail
to detect at least one half of cases of abruption. When the ultrasound seems
to show an abruption, the likelihood that there is indeed an abruption is high.
(2)
2.7 Management
The management of placental abruption depends on the presentation, the gestational
age, and the condition of the fetus and the mother. It is important to make
decisions about management on a case-by-case basis.
It is reasonable in cases of fetal death, regardless of gestational age, to
allow the mother to attempt a vaginal delivery as long as the mother is stable
and there are no other contraindications. In cases of abruption the uterus usually
contracts vigorously and labour progresses rapidly. Amniotomy frequently speeds
up delivery.
Placental abruption carries a significant risk of coagulopathy and hypovolemic
shock. Adequate intravenous access, attention to the amount of blood loss, and
replacement of volume, red blood cells, and coagulation factors is important.
Blood should be taken for complete blood count, coagulation factors and type
and crossmatch. (2)
2.8 Trauma in Pregnancy
In cases of blunt abdominal trauma during pregnancy, more than 70% of fetal
losses result from placenta abruption. The mechanism of the abruption in cases
of blunt trauma is partially based on the elasticity of the uterus which allows
deformation of its shape with trauma, and the non-elasticity of the placenta,
which does not deform with trauma. This mechanism creates a shearing effect
at the uteroplacental interface. (6)
All women beyond 20 – 24 weeks of gestational age who suffer blunt trauma
should be monitored for a minimum of four hours. With any non-reassuring finding
such as frequent uterine contractions, abnormal fetal heart tones, or any serious
maternal signs or symptoms, the mother should be observed longer. In three separate
studies, the presence of frequent uterine contractions has been the most sensitive
predictor of placental abruption. (6)
Management decisions in the care of a mother suffering from blunt trauma must
be based on maternal condition, gestational age of the fetus and careful monitoring
of clinical signs, keeping in mind the possibility of placental abruption. (6)
3.0 Placenta Previa
3.1 Introduction
Placenta previa is an implantation of the placenta that overlies or is within
2 cm of the internal cervical os. The condition is described as a complete previa
when it covers the os and as a marginal previa when the edge lies within 2 cm
of the os. Any suspected low-lying placenta seen by transabdominal scan should
be evaluated by a transvaginal scan. (1)
When the cervix has not dilated and the placental edge is located within one
cm of the internal os, bleeding usually occurs with labor and a cesarean section
must be done. When the placental edge is located one to two cm away from the
undilated cervical os, the clinical course cannot be definitely predicted. When
the edge is at least two cm away from the os, it is not considered a placenta
previa. (4)
Types of Placenta Previa
3.2 Incidence
Placenta previa is found in approximately 0.5% to 1% of all pregnancies. It
can be fatal in 0.03% of cases. It is more common in multiparous than in nulliparous
women occurring in one in 1,500 nulliparous women and as many as one in 20 grand
multiparous women. (4)
3.3 Risk Factors
Several risk factors have been found in association with placenta previa. A
prior cesarean section is the most significant risk factor. The risk is one
in 200 deliveries after one previous cesarean section, and even higher after
repeated cesarean sections. Other risk factors include pregnancy termination,
intrauterine surgery, smoking, multifetal gestation, increased parity, and increasing
maternal age. (7)
3.4 Pathophysiology
The exact pathophysiology is unknown but it is thought to result from scarring
in the endometrium because placenta previa is more frequent in women who are
older, multiparous or who have had prior cesarean sections or uterine curettage.
This prior experience of the endometrium can lead to poor vascularity of this
tissue and a thinner myometrium. The embryo implants in healthier tissue which
would be the healthier tissue of the lower uterine segment. The fact that there
is a six-fold increase in implantation at the site of a previous lower uterine
segment incision is not explained by this theory. (4)
3.5 Clinical Presentation
Placenta previa is commonly seen as an incidental finding on transabdominal
ultrasounds performed at 20-24 weeks gestation. It is present in only 0.4% of
pregnancies at term. The migration of the placenta away from the lower uterine
segment is caused by growth of placental trophoblasts toward the fundus with
its richer blood supply. The lower uterine segment also elongates over time.
(1)
Smith performed a prospective ultrasound study comparing findings with transabdominal
scanning and transvaginal scanning. In this study landmarks such as the cervical
os and the edge of the placenta were poorly seen 50% of the time with transabdominal
scanning. Also, the assessment of placental localization was changed in 26%
of cases when transvaginal scanning was done after transabdominal scanning.
(8)
Placenta previa which is symptomatic usually presents as vaginal bleeding in
the late second or third trimester, often occurring after sexual intercourse.
This bleeding is painless unless labor or placental abruption has occurred.
The first sign of bleeding is usually not sufficient to produce hemodynamic
instability or to threaten the fetus in the absence of digital examination or
cervical instrumentation. (1)
3.6 Neonatal Outcomes
Neonatal complications significantly associated with placenta previa include
major congenital anomalies (odds ratio [OR] 2.48), respiratory distress syndrome
(OR) 4.94, and anemia (OR) 2.65. The perinatal mortality rate associated with
placenta previa was 2.3% (compared with 0.78% in controls) and was explained
by gestation age at delivery, occurrence of congenital anomalies, and maternal
age. (9)
3.7 Management
In general women bleeding from placenta previa are admitted to the hospital
for an initial assessment. Transabdominal and, if possible, transvaginal ultrasonography
are important steps in the assessment, as well as estimation of blood loss,
complete blood count, and typing and crossmatching of blood. Decisions about
management are based on gestational age of the fetus, amount of blood lost or
being lost, and the condition of the mother and her fetus. Since most neonatal
morbidity and mortality associated with placenta previa results from complications
of prematurity, an important goal is to prolong the pregnancy until fetal lung
maturity is achieved if possible.
If the evaluation of an antepartum hemorrhage has to be done in a setting where
there is no ultrasonography available, a double setup can be arranged. In the
face of significant bleeding and uncertainty about the location of the placenta,
the patient can be taken to the operating theatre where all is in readiness
for an emergent cesearean section. A useful sign is a high presenting part by
abdominal palpation. The high presenting part is due to the placenta filling
the lower uterine segment. A digital exam in the case of a central placenta
previa may provoke an uncontrollable hemorrhage. After inserting a large bore
intravenous catheter, a gentle digital exam can be performed in the theatre
to determine if the presenting part is the placenta. If the examiner feels that
a central placenta previa is present, an immediate cesarean section can be done,
especially if significant bleeding is provoked. (18) If placenta
previa is ruled out with this digital exam a cesarean section may not be necessary.
If the cervix is fully dilated with cephalic presentation a vacuum extraction
or obstetrical forceps delivery may be possible.
A Cochrane review by Neilson in 2007 examined the question of what effect any
clinical intervention had in cases where it was likely that a pregnant woman
had placenta previa. His results showed there was no clear advantage or disadvantage
to a policy of home versus hospital care. Cervical cerclage may reduce the risk
of delivery before 34 weeks or the birth of a baby weighing less than two kgs.
(10)
If vaginal bleeding is occurring with preterm contractions, tocolytic agents
may be used safely to prolong gestation. Corticosteroids should be given to
women with pregnancies of 24 – 34 weeks gestation to accelerate fetal
lung maturity. The regimen for corticosteroids is either betamethasone, 12 mg
intramuscularly once in 24 hours for 2 doses, or dexamethasone 6 mg intramuscularly
repeated every 12 hours for a total of four doses.(20)
In the majority of cases a transverse lower uterine segment incision can be
used for delivery especially when the placenta is posterior and with a well-developed
lower uterine segment. In instances where the placenta is anteriorly located,
the surgeon must make the incision through the uterus and deliver the presenting
part expeditiously in order to avoid excessive blood loss for the fetus. Placenta
previa is often associated with fetal malpresentation especially transverse
lie. In these cases the uterine incision should be low vertical or classical.
(4)
Regional anesthesia has been successfully used for operations for placenta previa.
It has been reported that controlling the blood pressure during the operation
has not been a problem. However, the anesthetist may prefer general anesthesia
in cases of heavy blood loss before proceeding to the theatre. (4)
3.8 Placenta accreta associated with placenta previa
Placenta accreta is an abnormally firm attachment of placental villi to the
uterine wall accompanied by an absence of the normal intervening decidua basalis
and a fibrinoid layer called the layer of Nitabuch. Three types of placenta
accreta are recognized: (a) accreta – the placenta is attached directly
to the myometrium (b) increta – the placenta extends into the myometrium
and (c) percreta – the placenta extends through the entire myometrial
layer. (7)
The average incidence is approximately 1 in 7000 pregnancies and is highest
among women with placenta previa or a previous cesarean section. The presence
of placenta previa in a patient with a prior cesarean section is associated
with accreta in 10% to 35% of cases. With multiple cesarean sections, the risk
may be as high as 60% to 65%. Other risk factors include advanced maternal age,
multiparity, and previous uterine curettage. The incidence of placenta accreta
is rising, mainly due to the rise in cesarean sections. (11)
In most cases of placenta accreta the principal concern is control of hemorrhage
at the time of delivery of the placenta. In the majority of reported cases this
has been achieved by hysterectomy. Fox reported maternal mortality of 5.8% to
6.6% among women who underwent immediate hysterectomy. Attempts at conservative
management were associated with maternal mortality of 12.4% and 28.3%. (12)
Reported approaches to conservative management of placenta accreta include curettage
of placental fragments, oversewing of the placental bed, ligation of the uterine
arteries, or ligation of the anterior divisions of the internal iliac arteries.
(12)
The definitive diagnosis of placenta accreta can only be made by histological
examination. The clinical diagnosis made after or during delivery of the placenta
is based on symptoms of bleeding, retained placenta and unsuccessful manual
removal of the placenta. (12)
Komulainen describes two cases of conservatively managed placenta accreta in
Finland. One of these cases will be described for the purposes of illustration.
In this case the patient was a 40-year old women, G8P7, who had a forceps delivery
of a healthy baby girl with 6/8 Apgar scores. Manual removal of the placenta
was attempted but it was firmly attached and only partially removed. An immediate
blood loss of 2000 ml was observed. The bleeding stopped after more of the placenta
was “partly torn out.” Total hysterectomy was considered but not
done because of religious reasons. The ensuing treatment included 12 hours of
intravenous oxytocin and antibiotics. Hospital stay lasted for three weeks.
The patient went home well, had weekly checkups, and a dilatation and curettage
were performed 4 months after delivery. The uterine cavity at that time was
normally shaped and the histopathology revealed some remnants of residual placenta.
At the age of 45 this patient again conceived and delivered a ninth time. At
the time of cesarean section a recurrent placenta accreta was diagnosed and
total hysterectomy was required. (12)
The subject of placenta accreta is discussed in this section to alert the doctor
faced with managing placenta previa of the possibility of continuing hemorrhaging
after removal of a placenta previa due to placenta accreta.
4.0 Vasa Previa
4.1 Introduction
The term vasa previa denotes the condition where fetal vessels course through
placental membranes unprotected by placenta or umbilical cord. A velamentous
insertion of the umbilical cord describes a condition where the cord inserts
into the membranes rather than its normal insertion directly into the placenta.
This velamentous insertion is the most common cause of vasa previa. Vasa previa
can also occur when fetal vessels course between lobes of the placenta with
one or more accessory lobes. Vasa previa is clinically important because of
the high risk of fetal exsanguination and death that occurs when the membranes
rupture, spontaneously or artificially, and the fetal vessels running through
the membranes also are disrupted. Loss of even small amounts of blood from the
fetal vessels can prove disastrous to the fetus because the fetal blood volume
is only about 80 – 100 mL/kg. (7)
The estimated incidence of vasa previa is approximately 1 in 2,500 deliveries.
The following are risk factors for vasa previa: a second-trimester low-lying
placenta, pregnancies in which the placenta has accessory lobes, and multiple
pregnancies. (7)
4.2 Diagnostic approach
Vasa previa is most commonly suspected when rupture of the membranes
is accompanied by vaginal bleeding and fetal distress or death. The diagnosis
is often confirmed only when the placenta is inspected after delivery and the
position of the fetal vessels is confirmed. Rarely the diagnosis can be made
when the examiner's fingers palpate fetal vessels running through the membranes.
Numerous reports and studies have demonstrated that vasa previa can be diagnosed
prenatally with ultrasonography. (7)
4.3 Therapeutic approach
Good outcomes in the presence of vasa previa depend on diagnosis and delivery
by cesarean section before rupture of membranes. In a multicenter study by Oyelese
and colleagues of 155 cases of vasa previa, 61 of the cases were diagnosed prenatally.
Perinatal mortality was 56% in the undiagnosed cases, and only 4% in the cases
diagnosed before rupture of membranes. Two-thirds of the women had a low-lying
placenta in the second trimester, whereas, by the time of delivery, only one
third (20%) of these had a low-lying placenta. In women with a diagnosed vasa
previa, the optimal gestational age for cesarean delivery is 35 to 36 weeks.
(7)
5.0 Antepartum Bleeding of Unknown Origin (ABUO)
5.1 Overview
The most common significant reasons for bleeding after the twentieth week of
pregnancy are placenta previa and placental abruption. However, bleeding can
also be caused by other conditions of the cervix, such as cervical ectropion,
cervical polyp, cervicitis, or cervical cancer. The onset of normal labor is
often accompanied by a small amount of bleeding, or blood-tinged mucus, (bloody
show). Many pregnant women experience some bleeding after sexual intercourse
or a digital vaginal exam. A history, a physical examination, and ultrasonography
are important, initial first steps in evaluating. A gentle, sterile speculum
exam can be safely done in instances where ultrasonography is not available.
A digital exam should not be done before ultrasonography can be done to exclude
placenta previa. (1)
Despite an exhaustive search for the cause of antenatal bleeding the reason
for the bleeding will remain unknown in 2% to 3% of women. Magann and colleagues
undertook a study to determine the incidence and adverse pregnancy consequences
of bleeding of an unknown etiology in the second half of pregnancy and proposed
a strategy for management of these pregnancies. (14)
5.2 Incidence and Consequences of ABUO.
One subgroup of women studied by Magann with bleeding before 20 weeks or bleeding
in the first and second trimester had an incidence of ABUO of 8%. In the second
subgroup studied the bleeding was confined to the second and third trimester
and the incidence was 2%. (14) Current management of pregnancies
with ABUO requires a careful physical examination and an ultrasound to evaluate
the origin of bleeding. A second trimester ultrasound for the detection of fetal
congenital anomalies should be done if the bleeding occurs in the second trimester.
If the bleeding is accompanied by contractions, then the risk of delivery is
high. Corticosteroids should be administered if the pregnancy is between 28
and 34 weeks. (14)
6.0 Hypertensive Disorders of Pregnancy
6.1 Introduction
Hypertension is the most common medical disorder occurring during pregnancy.
Approximately 70% of women diagnosed with hypertension during pregnancy will
have gestational hypertension-preeclampsia, which describes a spectrum of hypertensive
disorders, each of which requires specific thought and management. In the face
of hypertension late in pregnancy the decision between expectant management
and delivery depends on fetal gestation age, fetal status, and severity of the
maternal condition at the time of evaluation. (15)
6.2 Definition and Classification
Gestational hypertension is defined only in women who are known to be normotensive
before pregnancy and before 20 weeks’ gestation. A systolic BP of at least
140 mm Hg and/or a diastolic BP of at least 90 mm Hg on at least two occasions
at least 6 hours apart after the 20th week of pregnancy make the diagnosis of
gestational hypertension. This condition is considered to be severe if there
is sustained elevation in systolic BP to at least 160 mm Hg and/or in diastolic
BP to at least 110 mm Hg for at least 6 hours. (15)
Preeclampsia is defined as gestational hypertension plus proteinuria. The proteinuria
is usually documented by a concentration of at least 30 mg/dL (1+) on a urinary
dipstick test. At least two random sample urine specimens collected at least
six hours apart further reinforce the presence or absence of proteinuria. The
concentration of urinary protein in random urine samples is highly variable.
(15)
6.3 Etiology and pathophysiology
The etiology of preeclampsia is unknown. Some of the potential etiologies under
investigation include abnormal trophoblast invasion of uterine blood vessels,
immunological intolerance between fetoplacental and maternal tissues, dietary
deficiencies, and genetic abnormalities. (15)
Preeclampsia causes numerous pathophysiologic abnormalities including placental
ischemia, generalized vasospasm, abnormal hemostasis, vascular endothelial dysfunction,
leukocyte activation, and changes in various cytokines as well as in insulin
resistance. (15)
One of the pathogenetic explanations for the development of preeclampsia is
a maladaptation of the immune system to paternal antigens. Some researchers
feel that a local immune hyperreactivity may cause incomplete trophoblastic
invasion of the uterine spiral arteries. This incomplete trophoblastic invasion
could expose the placental site to vasoconstriction and the eventual development
of preeclampsia. Immune deficiency, whether induced by HIV or any other cause,
could therefore inhibit a tendency to immune hyperreactivity and thus prevent
the development of preeclampsia. (17)
A study was carried out in Soweto, South Africa, where HIV seroprevalence was
29.3%, and the prevalence of preeclampsia/eclampsia was 7.8%, to investigate
the relationship between HIV and preeclampsia. A total sample of 2,600 women
was studied. The HIV seroprevalence rate was 27.1%. Hypertension was found in
17.3% of women, with 5.3% having preeclampsia-eclampsia. The rate of preeclampsia-eclampsia
was 5.2% in HIV-negative and 5.7% in HIV-positive women. Thus, HIV seropositivity
was not associated with any reduction in the risk of developing preeclampsia-eclampsia.
(17)
6.4 Prediction and prevention
There is no single screening test at the present time that is reliable and cost-effective
for predicting preeclampsia. There has been a lively interest in clinical reports
and randomized trials describing the use of various methods to reduce the rate
and/or the severity of preeclampsia over the past two decades. At the present
time there is no known supplementation or medicine that can be routinely prescribed
for the prevention of preeclampsia in nulliparous women. (15)
6.5 Antepartum management of preeclampsia
The management of women with mild gestational hypertension or mild preeclampsia
depends on maternal and fetal evaluation. Sibai recommends induction of labor
for delivery in these women at 40 or more weeks gestation, in women at 37 weeks
with a favorable cervix who are noncompliant, and in women with labor or rupture
of membranes, abnormal fetal testing or intrauterine growth restriction.
The maternal and fetal condition should be closely followed in women who remain
undelivered with mild preeclampsia. Sibai recommends a regular diet with no
salt restriction, reduced activity but not strict bedrest, nor using diuretics
or antihypertensive medications. The nonuse of antihypertensives is based on
the potential of these medicines to mask the diagnosis of the onset of severe
disease. Also, the current data suggest that antihypertensive therapy in women
with mild gestational hypertension or preeclampsia does not improve perinatal
outcome. (15)
The definition of severe preeclampsia implies various organ dysfunctions including
evidence of hemolysis, elevated liver enzymes, and low platelets, which is known
as the HELLP syndrome. The clinical course of severe preeclampsia may lead to
progressive deterioration in both the maternal and fetal conditions. Because
of the increased rates of maternal morbidity and mortality and significant risks
to the fetus, there is universal agreement that all patients with severe preeclampsia
developing after 34 weeks gestation should deliver. (15)
There is disagreement about management of patients with severe preeclampsia
before 34 weeks gestation where the maternal condition is stable and the fetal
condition is reassuring. Friedman and colleagues reviewed the expectant management
of severe preeclampsia remote from term and found that in some cases delaying
delivery was beneficial to the fetus and not harmful to the mother. The final
conclusion of their study was that expectant management of severe preeclampsia
should be undertaken only at tertiary care facilities. (16)
6.6 Intrapartum management
The goals of management of a patient in labor with any degree of preeclampsia
include early detection of any fetal heart rate abnormalities, early detection
of any deterioration in the condition of the mother, and prevention of any maternal
complications. Continuous fetal heart rate monitoring or at least frequent intermittent
heart rate monitoring should be used to monitor the condition of the fetus.
Blood pressure recordings and urine output should be watched closely. A normal
progress in labor can result in a vaginal delivery. Cesarean section should
be done for the usual obstetrical indications. The methods of choice for anesthesia
in cases of cesarean section include either epidural, spinal, or combined techniques
or regional anesthesia. General anesthesia increases the risk of aspiration
and failed intubation due to airway edema and is associated with marked increases
in blood pressures during intubation and extubation. (15)
The drug of choice for the prevention of convulsions in severely preeclamptic
patients is magnesium sulfate. The benefit of magnesium sulfate in preventing
convulsions in women with mild preeclampsia remains unclear. (15)
The objective of treating acute severe hypertension is to prevent potential
cerebrovascular and cardiovascular complications for the mother. The most commonly
used antihypertensive medicine is intravenous hydralazine given as bolus injections
of 5 – 10 mg every 15 – 20 minutes for a maximum dose of 30 mg.
Rapid decreases in blood pressure in labor are not desirable because of the
risk of fetal compromise. (15)
As mentioned the drug of choice in preventing the onset of a convulsion in severe
preeclampsia as well as recurrent convulsions in eclampsia is magnesium sulfate.
Sibai recommends giving a loading dose of magnesium sulfate of 6 grams over
15 – 20 minutes, followed by a continuous infusion of 2 gm/hour intravenously.
Sibai does not recommend monitoring serum magnesium levels during the infusion
because there is no established serum magnesium level that is considered “therapeutic.”
Serum magnesium levels are recommended in a patient with renal dysfunction and
decreased or absent reflexes. (19) Magnesium sulfate infusion
should be stopped in a patient with absent reflexes because this may indicate
a toxic level of magnesium.
Approximately 10% of elamptic women will have a second convulsion after receiving
magnesium sulfate. In these women, another bolus of 2 grams of magnesium sulfate
can be given intravenously over 3 – 5 minutes. Occasionally a patient
will continue to have convulsions while receiving adequate doses of magnesium
sulfate. Sibai recommends giving sodium amobarbital, 250 mg intravenously over
3 – 5 minutes for a recurrent seizure. (19)
Women receiving magnesium sulfate should have a Foley catheter and their urine
output should be monitored every four hours. Deep tendon reflexes should also
be checked every four hours while magnesium is being infused.
6.7 Postpartum management
The blood pressure, urinary output, and fluid intake should be carefully monitored
during the immediate postpartum period. Women who have received large amount
of intravenous fluids during labor are at risk for developing pulmonary edema.
In most women with gestational hypertension the blood pressure normalizes during
the first week postpartum. Severe preeclampsia and eclampsia may develop postpartum
for the first time. Women with severe headaches, visual changes, epigastric
pain with nausea or vomiting require hospitalization and evaluation. Many authorities
give women with these symptoms 24 hours of magnesium sulfate even postpartum.
(15)
6.8 Management of eclampsia
The diagnosis of eclampsia is secure in the presence of generalized edema, hypertension,
proteinuria, and convulsions. The first priority in managing eclampsia is to
prevent maternal injury and to support the respiratory and cardiovascular functions
of the mother. Immediately after an eclamptic convulsion the airway of the mother
must be secured and maternal oxygenation supported. The women should be in a
bed with padded siderails and she should be in lateral decubitus position to
minimize the risk of aspiration.
As mentioned previously the woman should receive a loading dose of magnesium
sulfate followed by a maintenance dose to prevent recurrent seizures. The next
step in management is to reduce the blood pressure to a safe range avoiding
at the same time significant hypotension. Sibai’s recommendation is to
keep the systolic blood pressure between 140 and 160 mm Hg and the diastolic
blood pressure between 90 and 110 mm Hg. The rationale for these ranges of blood
pressure is to avoid potential reduction in either uteroplacental blood flow
or cerebral perfusion pressure.
The presence of eclampsia is not an absolute indication for cesarean section.
Sibai recommends cesarean section for eclamptic mothers with a gestational age
before 30 weeks who are not in labor. Patients having labor or rupture of membranes
are allowed to deliver vaginally in the absence of obstetric complications.
Labor is usually induced with diluted intravenous pitocin.(20)
7.0 Recommendations
1. Placental abruption, or prelabor separation of a placenta, normally located
in the uterine fundus, presents in a variety of ways late in pregnancy, but
almost always accompanied by uterine pain and uterine irritability.
2. A large area of abruption presents as a life-threatening emergency, often
but not always accompanied by vaginal bleeding. A mother with signs of shock,
anemia, irritable or hypertonic uterus, and vaginal bleeding must be investigated
for placental abruption.
3. A small abruption may have minimal bleeding and little or not consequences
for the mother or the fetus.
4. Placenta previa is an implantation of the placenta that overlies or is within
2 cm of the internal cervical os. Ultrasonography is a useful diagnostic tool
to localize the position of the placenta.
5. Management of placenta previa is based on the severity of the bleeding, the
condition of the mother and fetus, and the gestational age of the pregnancy.
6. Placenta accreta is an abnormally firm attachment of placental villi to the
uterine wall. Placenta accreta may result in incomplete separation of the placenta
postpartum and serious portpartum hemorrhage. The majority of reported cases
of placenta accrete have been managed by postpartum hysterectomy.
7. Vasa previa is a condition where fetal vessels course through placental membranes
unprotected by placenta or umbilical cord. Vasa previa should be suspected when
rupture of the membranes is accompanied by important vaginal bleeding, fetal
distress, or fetal death. A prompt cesarean section can sometimes save the life
of the fetus.
8. Hypertensive disorders of pregnancy include chronic hypertension present
before pregnancy, chronic hypertension with superimposed preeclampsia, gestational
hypertension without proteinuria, preeeclampsia with proteinuria, and eclampsia.
9. Severe preeclampsia implies multiple organ dysfunction and is best managed
by delivery no matter what the gestational age of the pregnancy, except for
conservative management at a tertiary care center. The drug of choice to prevent
seizures in severely preeclamptic patients is magnesium sulfate.
Sue Makin MD, FACOG, Diplomate ABOG
Mulanje Mission Hospital
Mulanje, Malawi
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