Fetal complications in later pregnancy

Published on 09/03/2015 by admin

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Chapter 33 Fetal complications in later pregnancy

Jackie Chua, Michael Flynn

Intrauterine fetal death (IUFD)

Definition. IUFD is the delivery of a live fetus with no signs of life after 20 weeks. The intrauterine diagnosis is via the absence of fetal heart sounds and fetal movements. Signs of longer duration demise include Spalding’s sign (overlapping skull bones on X-ray) or Robert’s sign (gas in the fetal cardiovascular system). About 50% of all IUFDs occur at over 37 weeks gestation.

Aetiology

Aetiology varies with gestational age and between developed and non-developed countries. Within developed countries, near-term the aetiologies include:

• unexplained
• intrauterine growth restriction (IUGR)
• placental abruption
• infection
• chromosomal and congenital anomalies

Complications

• infections, especially with rupture of membranes
• maternal distress
• coagulopathy and disseminated intravascular coagulopathy

Coagulopathy and disseminated intravascular coagulopathy

This can occur when gestation is over 14 weeks, and generally when the fetus has been dead for over 4 weeks. There is a slow reduction in fibrinogen of about 500 mg/L per week, which is unlikely to be associated with bleeding tendency until levels are lower than 1 g/L. The coagulopathy is due to fibrinogen consumption with release of thromboplastins from retained products of conception. There may also be raised fibrin degradation products, prothrombin time and activated partial thromboplastin time with a reduction in platelets. Disseminated intravascular coagulopathy occurs in one-third of patients with IUFD for over 4 weeks. Spontaneous labour occurs in 80% of cases within 2 weeks, with only 10% undelivered after 3 weeks.

Investigations

• photograph of the fetus
• X-ray/magnetic resonance imaging (MRI)
• cytogenetics: blood, skin, placenta/amnion
• autopsy
• bacteriology: swabs of the fetus and placenta
• maternal: blood group and antibodies, full blood count, Kleihauer test, antiphospholipid antibodies, HbA1c, Toxoplasma, cytomegalovirus and rubella serology, thyroid function

Delivery of the dead fetus

Prostaglandins

Prostaglandin pessaries or gel

• Give prostaglandin E2 analogue 1–2 mg via gel or sustained release, as in term induction of labour.
• Contraindications include hypersensitivity to prostaglandin and induction of labour at term.
• Cautious use is required with the concomitant use of oxytocin after previous uterine surgery and in patients with obstructive airways disease.

Vaginal

Misoprostol (prostaglandin E1 analogue)

• This appears to be effective in induction of IUFD. The possibility of uterine rupture with previous caesarean section is noted.
• It is the method of choice with dose decreasing from mid-trimester to late-third trimester.

Oxytocin

• If the cervix is favourable, artificial rupture of membranes may be performed to reduce induction to delivery interval without a significant rise in infection rates.

Caesarean section

• Indications include major placenta praevia, severe cephalopelvic disproportion, previous classical caesarean section or more than two previous caesarean sections, the presence of uterine rupture or transverse lie and unsuccessful version.

Intrauterine growth restriction (IUGR)

Definition. IUGR is where the estimated birth weight is less than the tenth percentile for gestational age (but some neonates with IUGR will be heavier). The clinical relevance of IUGR is a four-fold rise in intrauterine fetal death, greater risk of birth hypoxia, neonatal complications and impaired neurodevelopment. The majority of term IUGRs have no morbidity or mortality.

Causes

• idiopathic, racial
• uteroplacental insufficiency as a result of pre-eclampsia, or abruption
• chromosomal abnormalities
• structural/anatomical abnormalities
• infections
• maternal causes (e.g. smoking, drugs, alcohol, nutrition)
• multiple pregnancies

Screening

• Clinical assessment alone detects fewer than 50% of cases. This includes abdominal palpation and symphysial fundal height, which has a sensitivity of 60%–74% and a false-positive rate of 55%.

Diagnosis

• Abdominal circumference and estimated fetal weight by ultrasound are the most accurate diagnostic measurements to predict growth retardation. Ultrasound scan measuring abdominal circumference in the third trimester can detect 85% of IUGRs.
• There used to be differentiation between symmetrical and asymmetrical IUGR, but it is not generally used any more as an indicator for chromosome type of growth restriction.
• IUGR and polyhydramnios can be an indication for chromosome abnormality.

Management

• ultrasound

• biometry and estimated fetal weight +/–10%
• Doppler: monitoring umbilical artery Doppler for brain sparing then decompensation type of parameters

— other blood vessels looked at include middle cerebral artery, ductus venosus and umbilical vein
— uterine artery for presence or absence of a notch in the waveform may indicate high risk for placental insufficiency in first and second trimester

• amniotic fluid index: decreases

• biophysical profile: late signs
• cardiotocography (CTG): late signs
• delivery

• timing difficult
• Growth Restriction Intervention Trial (GRIT) trial: no difference in total perinatal deaths between immediate versus delayed delivery group and both had similar 2-year neurological outcomes
• Doppler best indicator for delivery after 29 weeks with ductus venosus a good predictor of intact survival
• Cochrane for high-risk and low-risk pregnancies and Doppler surveillance found no benefit with an increased intervention rate

Disorders of amniotic fluid volume

• amniotic fluid homeostasis: fetal urine production and swallowing, secretions and transfer across membranes

Screening

• abdominal palpation
• increased abdominal girth and difficulty feeling fetal parts
• smaller than expected

Diagnosis

• ultrasound
• subjective assessment
• objective assessment
• amniotic fluid index
• deepest vertical pocket (twins)

Polyhydramnios

Risk factors

• fetal abnormalities (neural tube defects, gastrointestinal defects limiting swallowing of liquor)
• hydrops fetalis
• multiple pregnancy, especially monozygotic twins
• maternal diabetes
• idiopathic

Complications of polyhydramnios

• preterm rupture of membranes
• premature labour
• unstable lie and fetal malpresentation
• cord prolapse
• postpartum haemorrhage, placental abruption
• maternal discomfort

Management

• ultrasound examination of fetus and assessment of amount of liquor
• glucose tolerance test
• indomethacin: risk of premature closure of ductus arteriosus
• close monitoring in high-risk unit with possible amnio reduction

Oligohydramnios

Factors associated with reduced amniotic fluid volume

• placental insufficiency and IUGR
• iatrogenic
• fetal abnormalities (renal or renal tract abnormalities)
• premature rupture of membranes
• post-term pregnancy

Complications of oligohydramnios

• cord compression and fetal distress
• increased perinatal morbidity and mortality
• postural/musculoskeletal deformities
• pulmonary hypoplasia, especially if early onset or prolonged

Management

• ultrasound examination of fetus for anomalies
• assessment of fetal wellbeing
• assessment for rupture of membranes

Further reading

Baschat A.A., Galan H.L., Bhides A., et al. Doppler and biophysical assessment in growth restricted fetuses: distribution of test results. Ultrasound in Obstetrics and Gynecology. 2006;27:41-47.

Bricker I., Neilson J.P., Dowswell T. Routine ultrasound in late pregnancy (after 24 weeks’ gestation). Cochrane Database of Systematic Reviews. 2008. Issue 4. Art. No. CD001451. DOI: 10.1002/14651858

GRIT Study Group. Wellbeing at 2 years of age in the Growth Restriction Intervention Trial (GRIT): multicentre randomized controlled trial. Lancet. 2004;364:513-520.

Grivell R.M., Wong L., Bhatia V. Regimens of fetal surveillance for impaired fetal growth. Cochrane Database of Systematic Reviews. 2009. Issue 1. Art. No. CD007113. DOI: 10.1002/14651858

Kinzler W.L., Vintzileos A.M. Fetal growth restriction: a modern approach. Current Opinion in Obstetrics and Gynecology. 2008;20:125-131.

Lalor J.G., Fawole B., Alfirevic Z., Devane D. Biophysical profile for fetal assessment in high risk pregnancies. Cochrane Database of Systematic Reviews. 2008. Issue 1. Art. No.: CD000038. DOI: 10.1002/14651858

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