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34. Overdistended Uterus
34.1 Introduction
Overdistended uterus is said to be present when the height of the fundus is greater than the gestational age. First consideration of this condition is wrong dates of last menstrual period. Other possible conditions are multiple pregnancy, polyhydramnios, foetal macrosomia, foetal hydrops and presence of big uterine myomas. All these obstetric complications have increased risk to the mother and foetus leading to increased maternal and perinatal mortality and morbidity. Each obstetric condition needs to be diagnosed for management. Emergency ultrasound in cases where the condition is not diagnosed before plays a vital role for proper diagnosis.
34.2 Diagnosis of Overdistended Uterus
34.2.1 Clinical Management
Symphyseal-fundal height is a screening tool for abnormal growth of foetus and uterine distension. Foetomaternal factors that may increase SFH are amount of amniotic fluid, amount of abdominal fat, presence of large fibroids and multifoetal pregnancy. Thorough clinical history of the patients to find out the duration of symptoms, confirmation of gestational weeks and whether she was already diagnosed to have one of these conditions are important.
Acute onset of sudden enlargement of the uterus with pain can be a presenting symptom of acute polyhydramnios.
If patient presents in shock and severe pallor, possibility of concealed accidental haemorrhage has also to be kept in mind.
Family history of diabetes mellitus or patient already diagnosed with DM usually means foetal macrosomia.
Patients with Rh-negative blood group have a possibility of foetal hydrops. Careful clinical examination can diagnose the causes of overdistension.
Associated firm localised swelling on uterine surface confirms uterine leiomyoma. She may also give history that she is a diagnosed case of fibromyoma.
Confirmation of accuracy of gestational age is very important to rule out wrong dates.
If only one foetus is felt on abdominal examination, then consider wrong dates, macrosomia or polyhydramnios.
If multiple foetal poles and multiple parts are felt, then multiple pregnancy is confirmed by ultrasound.
34.2.2 General Management
Patient needs rest and propped-up position in severe cases especially with acute polyhydramnios and multiple pregnancy. Preterm labour is a known complication of overdistension for any causes. If there is shortening of the cervix on examination or there is uterine contraction, steroid for foetal lung maturity must be given in preterm multiple pregnancy and hydramnios.
During labour close monitoring is done and delivery should occur in tertiary centres. Wide bore intravenous cannula should be kept in place in advance as postpartum haemorrhage is common in overdistension. Active management of the third stage is routinely done although it does not prevent PPH in all cases. Prostaglandin injections for controlling haemorrhage should be readily available. Blood should be kept crossmatched.
34.3 Management for Specific Conditions
34.3.1 Polyhydramnios
Clinically polyhydramnios is said to be present when AFI is more than 95th centile for gestational age or maximum vertical pool length of more than or equal to 8 cm and AFI more than or equal to 25 cm. Clinically, detectable polyhydramnios occurs in 0.5–1% of pregnancies [1–7].
Patients usually present with respiratory embarrassment. Abdominal pain, preterm labour and PPROM are common presentations. There may be palpitation, leg oedema, vulval oedema and abdominal oedema. Patient may also have complains of aggravated piles and varicosities in lower extremities. Maternal mirror syndrome in which maternal condition mimics the foetus with signs of preeclampsia may be the presenting feature in foetal hydrops. Abdominal skin is stretched, shiny, oedematous and tense. Fluid thrill is found along with difficulty in palpation of foetal parts with presence of external ballottement and difficulty in locating foetal heart sound. Malpresentation is often associated.
34.3.2 Causes of Polyhydramnios
- 1.
Idiopathic
- 2.
Maternal causes:
- (a)
Maternal diabetes
- (b)
Maternal alloimmunisation
- (c)
Cardiac or renal disease due to excessive transudation
- (d)
Maternal substance abuse
- (a)
- 3.
Foetal causes:
- (a)
Parvovirus infection
- (b)
Congenital syphilis
- (c)
Foetal anomalies:
CNS anomaly: anencephaly, spina bifida, meningocele
Oesophageal atresia, trachea-oesophageal fistula
High gut obstruction: duodenal atresia
Thoracic tumours
Facial dysmorphism, congenital goitre, cystic hygroma.
Congenital diaphragmatic hernia
Foetal Bartter syndrome
Myotonic dystrophy
Foetal sacrococcygeal teratoma
Foetal vein of Galen syndrome
TTTS in multiple pregnancy
- (a)
- 4.
Placental causes: placental tumours
All these conditions need to be diagnosed as each of them has specific management. Detailed history of drug exposure, maternal diabetes, prior prenatal screening for aneuploidy, family history of myotonic dystrophy or past history of skeletal dysplasia or arthrogryposis and red cell alloimmunisation are very important.
34.3.3 Investigations for Polyhydramnios
34.3.3.1 Maternal
Glucose tolerance test, blood grouping and antibody titre if not done already.
34.3.3.2 USG
- 1.
Degree of polyhydramnios.
- 2.
Presence of foetal anomalies especially those which impede foetal swallowing should be looked for. Possible USG findings are markers of chromosomal defects, absence of stomach bubble or double bubble sign, diaphragmatic hernia, abnormal posture or absent movement which may suggest neuromuscular disorder and abnormal long bones which suggest skeletal dysplasia and are associated with polyhydramnios.
- 3.
Placental localisation, evidence of abruption and looking for any placental mass.
34.3.3.3 Doppler
Middle cerebral Doppler study for evidence of foetal anaemia, foetal cardiac scan and presence of tachyarrhythmia and evidence of TTTS are also essential for aetiological diagnosis.
34.3.3.4 Karyotyping
For anomalous foetus karyotyping also may be necessary.
34.3.3.5 Evidence of Infection
Serology for parvovirus and maternal screening for toxoplasmosis and cytomegalovirus can be linked up with foetal hydrops.
34.3.3.6 Maternal Complications of Polyhydramnios
There is increased risk of preterm delivery and perinatal mortality. Abnormal presentation leading to increased incidence of operative delivery is another maternal risk associated with polyhydramnios. Placental abruption due to rapid decompression is a grave complication. Other risks are dependent on aetiology. Cord prolapse, dysfunctional labour, retained placenta and postpartum haemorrhage are also common complications of gross polyhydramnios. Subinvolution of the uterus and puerperal sepsis are possible postpartum maternal risks.
34.3.3.7 Foetal Complications
There is increased perinatal mortality.
34.3.3.8 Treatment Options for Polyhydramnios
Counselling forms an important part of management. Even an USG is not sufficient to diagnose oesophageal atresia and tracheobronchial fistula, and these conditions are confirmed only after the baby is born so a guarded reassurance is necessary with apparently idiopathic cases of polyhydramnios. For mild cases expectant management is done. Indomethacin in a dose of 25 mg every 6 h till 32–34 weeks is also used by some authors, but it has a variety of foetal side effects including closure of ductus arteriosus, oligohydramnios and foetal renal damage although not all reports support these associations. Indomethacin reduces foetal urine production through direct renal effect.
Amnioreduction is done in severe cases if patient is symptomatic and prolongation of pregnancy is indicated. It is done with an 18–20 g needle under USG guidance to avoid the placenta and with a large syringe or with vacuum bottles till AFI is 10–20 cm. The uterus should be monitored for any contraction for 12–24 h, and follow-up at 1–3 weeks is indicated depending on severity. The procedure can be repeated if condition recurs [8].
Delivery is to be done in tertiary care, and involvement of neonatologist is necessary to manage newborns with prematurity and other high-risk neonates associated with polyhydramnios. AMTSL is routinely done for all cases, and close observation for PPH for 2 h following delivery may save maternal life.
34.3.4 Multiple Pregnancy
Use of assisted reproductive techniques has greatly increased the incidence of multiple pregnancy. Chorionicity of twins should be determined, and it is possible as early as first trimester. Routine first trimester USG is to be done in all patients with ART, family history of multiple pregnancy and elderly mothers as well as mothers having previous multiple pregnancy.
34.3.4.1 Maternofoetal Outcome in Multiple Pregnancy
Most common complications of multiple pregnancy are preterm labour and PPROM. Mean age of gestation in twins is 37 weeks and 31 weeks for triplets. Twins are usually smaller at any given gestational age than singletons. Twin-to-twin transfusion syndrome occurs in monozygotic twins due to vascular sharing of the placenta which leads to growth retardation of one foetus and cardiac failure of the other. Anaemia, preeclampsia and placenta praevia are common complications of multiple pregnancy and add to the mortality and morbidity of both mother and foetus. Higher-order multiple pregnancy has much worse outcome than twin.
34.3.4.2 Management of Multiple Pregnancy in Labour Room
Ultrasonography is used to ascertain the chorionicity, foetal growth and signs of TTTS. FGR is managed with regular monitoring and steroids for lung maturity. For severe TTTS, foetoscopic laser surgery can be done if available to divide vascular anastomoses. The presence of short cervix of less than 20 mm is a significantly higher risk of preterm labour and can be treated with steroid and progesterone. Tocolytics for short period can be used so that steroid works for lung maturity.
34.3.4.3 Delivery
If the patient is already in labour, IV cannula is fixed. Blood should be sent for crossmatching. If presentation of the first twin is cephalic, then vaginal delivery is attempted. For all other cases of non-vertex first twins, caesarean is a safer procedure.
The main risk of twin delivery is hypoxia for the second twin during protracted second stage and premature placental separation. Immediately after delivery of the first twin, continuous foetal monitoring of the second twin is to be done. After ascertaining the longitudinal lie, ARM is done and intravenous oxytocin is started. If the second twin is transverse, external cephalic version is done followed by ARM. If membrane is ruptured in transverse lie, internal podalic version in an expert hand can save the baby especially with cord prolapsed. In case of any signs of foetal distress with vertex presentation, vacuum extraction or breech extraction can be performed. Ideally, the second twin should be delivered within 30 min. The third stage of labour should be actively managed [9]. In case of higher-order multiple gestation, selective foetal reduction with injection of potassium chloride in such cases as early in pregnancy as possible can reduce its complication rates.
34.3.5 Foetal Macrosomia
Assessment of foetal weight by ultrasound is very important to know the possibility of vaginal delivery. Associated diabetes mellitus must be kept in mind, and adequate control during labour is necessary. Anticipation of prolonged labour and obstruction should be there, and partographic management is vital. The most dangerous complication is shoulder dystocia. By definition it is a delivery that requires additional obstetric manoeuvres to release the shoulders after gentle downward traction has failed [10]. It is usually unpredictable. Identification of risk factors and antenatal care plan that aims to modify them may reduce its incidence. RCOG guideline recommends elective CS in macrosomia (foetal weight >4.5 kg) with diabetes [11]. Previous history of shoulder dystocia also needs elective caesarean section. Management aims prevention of birth asphyxia while avoiding injury to foetus and mother.
First-line manoeuvres are McRoberts manoeuvre where woman is kept in supine position with hips acutely flexed and the knees closed to the chest which straightens lumbosacral angle allowing descent of the posterior shoulder. It has a success rate of 90%.
Directed suprapubic pressure continuously on the posterior aspect of anterior shoulder may facilitate its rotation to an oblique position, adduction of shoulders and reduction in bisacromial diameter. Second-line manoeuvres are delivery of posterior arm, Rubin’s manoeuvre, Wood’s screw and reverse Wood’s screw where the aim is to rotate the shoulders to 180° and enable delivery by bringing down anterior shoulder posteriorly.
Third-line manoeuvres are Zavanelli manoeuvre and symphysiotomy.
34.3.6 Fibroid in Pregnancy
Uterine leiomyomas are found in 4% of all pregnancies. Out of these 10–30% of women develop complications during pregnancy [12]. A detailed history should be taken to find out whether she is a known case of fibroid. In addition to large for date uterus, palpable lumps on the uterine surface may be felt which can be multiple. Spontaneous abortion rate i higher in pregnant women with fibroids compared with control subjects without fibroids (14% vs. 7.6%, respectively) [13]. If the placenta is situated near fibroid, chances of early pregnancy haemorrhage are also high [14]. Chances of having placenta praevia are also twofold higher in some studies [15, 16]. Large fibroids causing distortion of uterine cavities can cause foetal compression deformities like torticollis and dolichocephaly [17, 18]. Foetal malpresentation may also occur with large fibroids, multiple fibroids and fibroids in lower segment [16, 19] like breech, transverse or oblique lies. Incidence is reported to be 13.4% vs. 4.5% in controls [15, 20]. Tenderness over fibroids can be elicited in fibroid with so-called red degeneration which can lead to preterm labour or abortion.
USG is the mainstay of diagnosis, and this is also important for its location like subserous, interstitial or submucous or corporeal or cervical fibroid.
34.3.6.1 Management of Complications of Fibroid in Pregnancy
Management is basically conservative with reassurance in antenatal period. Special management is necessary if it is painful, previous myomectomy and abnormal presentation. In case of pain, symptomatic treatment is required with paracetamol in moderate pain, and opioids may be necessary in severe cases. Majority of pain is self-limiting and pregnancy is unaffected.
Vaginal delivery even in the presence of large uterine fibroids (>5 cm) should not be regarded as a contraindication, and a trial of labour should be allowed [16, 20].
Incidence of postpartum haemorrhage in fibroid is conflicting. Pooled data suggests a slight rise of its incidence (2.5% vs. 1.4%) [15]. Distortion of cavity and effect on myometrial contraction by fibroids are thought to be the causes of postpartum haemorrhage and may land up in peripartum hysterectomy. Active management of the third stage should be offered to all women with fibroid as a preventive measure. Incidence of retained placenta is also little higher (1.4% vs. 0.6%) [15].
In a systematic review, women with fibroids were at a 3.7-fold increased risk of caesarean delivery (48.8% vs. 13.3%, respectively) [15]. Elective CS is done in abnormal presentation with fibroid. Transabdominal USG and TVS is done to know the precise relationship of fibroids and presenting part and exclude other cases of malpresentation like placenta praevia. An experienced surgeon should do it in a planned way. Transverse incision is generally preferred, but midline may be required if fibroids are large and multiple. If the lower segment is occupied by a big fibroid, then options are myomectomy first and foetal extraction or an upper segment CS depending on the experience of the surgeon. The general rule is avoidance of fibroids wherever possible, and incision should be away from fibroid as it can warrant bleeding requiring blood transfusion, uterine artery ligation and/or puerperal hysterectomy [21, 22]. Myomectomy at the time of caesarean delivery should only be performed if there is difficulty in extraction of the baby and closure of the wound. Alternative ways of delivery of foetus should be kept in mind, like use of vacuum extraction of vertex or delivery as breech. Increased blood loss is anticipated and crossmatched blood should be ready. Risk of hysterectomy is very low but should be counselled beforehand.
Previous myomectomy may pose difficulty due to adhesion and intraoperative haemorrhage.
34.3.6.2 Myomectomy in Pregnancy
Some literatures have reported that antepartum myomectomy can be safely performed in the first and second trimester of pregnancy [23, 24]. Indications are severe pain from a degenerating subserosal or pedunculated fibroid, a large or rapidly growing fibroid or any large fibroid (>5 cm) located in the lower uterine segment.
Uterine artery ligation or uterine artery embolisation (UAE) may be done in selected cases of fibroids immediately after caesarean delivery which may reduce incidence of blood loss and chance of hysterectomy [25, 26].
Postpartum care includes monitoring of them as some intramural fibroid may become submucous polyp and may cause bleeding in late postpartum period and will need hysteroscopic removal in the near future.
34.4 Conclusion
Overdistended uterus poses problems to both mother and child. Management depends on aetiological factor. Anticipation of complications well in advance and preparedness to combat the complications by experienced obstetricians will save invaluable lives of mothers.
