Obstetric Disease Flashcards
Define obstetric cholestasis.
Chole- relates to the bile and bile ducts. Stasis refers to inactivity. Obstetric cholestasis is characterised by the reduced outflow of bile acids from the liver.
How many pregnancies are affected by obstetric cholestasis?
In England,obstetric cholestasis (also referred to as intrahepatic cholestasis of pregnancy) affects 0.7% of
pregnancies in multiethnic populations1 and 1.2–1.5% of women of Indian–Asian or Pakistani–Asian
origin.
How does obstetric cholestasis present?
Obstetric cholestasis typically present later in pregnancy, particularly in the third trimester.
Itching (pruritis) is the main symptom, particularly affecting the palms of the hands and soles of the feet.
Other symptoms are related to cholestasis and outflow obstruction in the bile ducts:
- Fatigue
- Dark urine
- Pale, greasy stools
- Jaundice
Importantly, there is no rash associated with obstetric cholestasis. If a rash is present, an alternative diagnosis should be considered, such as polymorphic eruption of pregnancy or pemphigoid gestationis.
What is the DDx of obstetric cholestasis?
Other causes of pruritus and deranged LFTs should be excluded, for example:
- Gallstones
- Acute fatty liver
- Autoimmune hepatitis
- Viral hepatitis
How do we diagnose obstetric cholestasis?
Women presenting with pruritus should have liver function tests and bile acids checked.
Obstetric cholestasis will cause:
- Abnormal liver function tests (LFTs), mainly ALT, AST and GGT
- Raised bile acids
It is normal for alkaline phosphatase (ALP) to increase in pregnancy. This is because the placenta produces ALP. A rise in ALP without other abnormal LFT results is usually due to placental production of ALP, rather than liver pathology.
How should obstetric cholestasis be monitored?
- Once obstetric cholestasis is diagnosed, it is reasonable to measure LFTs weekly until delivery.
- Postnatally, LFTs should be deferred for at least 10 days.
What is the risk of stillbirth for pregnancies complicated by obstetric cholestasis?
In a hospital setting, the current additional risk of stillbirth in obstetric cholestasis above that of the general population has not been determined but is likely to be small
What is the main risk of obstetric cholestasis?
Still birth
What are the other risks of obstetric cholestasis and what should be done?
- Obstetricians should be aware (and should advise women) that the incidence of premature birth, especially iatrogenic, is increased.
- Women should be advised of the increased likelihood of meconium passage in pregnancies affected by obstetric cholestasis.
- Women with obstetric cholestasis should be booked in under consultant-led, teambased care and give birth in a hospital unit.
Can fetal death be predicted and prevented in obstetric cholestasis?
- Poor outcome cannot currently be predicted by biochemical results and delivery decisions should not be based on results alone.
- No specific method of antenatal fetal monitoring for the prediction of fetal death can be recommended.
- Ultrasound and cardiotocography are not reliable methods for preventing fetal death in obstetric cholestasis.
- Continuous fetal monitoring in labour should be offered.
What is the immediate management of obstetric cholestasis?
- Conservative
- Wear cool, loose, cotton clothing
- Soak in a cool bath
- Apply ice packs for short periods to affected areas
- Topical emollients, e.g. Menthol 0.5% with aqueous cream
- Medical
- Antihistamines (eg. chlorphenamine) – improves sleep (sedative), but no impact on pruritus
- Ursodeoxycholic acid – improves pruritus and LFTs but no protection against still birth
- Vitamin K - a water-soluble preparation (menadiol sodium phosphate) must be used with a usual dose of 10 mg daily
How would obstetric cholestasis affect delivery of the foetus?
- Offer induction of labour at 37 weeks (and aim to deliver no later than 40 weeks) - particularly when the LFTs and bile acids are severely deranged
- Advise to deliver in labour ward, with continuous CTG monitoring
- A discussion should take place with women regarding induction of labour after 37+0 weeks of gestation.
- Women should be informed of the increased risk of perinatal morbidity from early intervention (after 37+0 weeks of gestation).
- Women should be informed that the case for intervention (after 37+0 weeks of gestation) may be stronger in those with more severe biochemical abnormality (transaminases and bile acids).
- Women should be informed of the increased risk of maternal morbidity from intervention at 37+0 weeks of gestation.
- Women should be informed of the inability to predict stillbirth if the pregnancy continues.
How should we counsel on obstetric cholestasis?
Define gestational diabetes, what is it caused by?
Gestational diabetes refers to diabetes triggered by pregnancy. It is caused by reduced insulin sensitivity during pregnancy, and resolves after birth.
What are the complications of gestational diabetes?
The most significant immediate complication of gestational diabetes is a large for dates fetus and macrosomia.
- Increased birthweight
- 10% preterm labour
- Polyhydramnios due to macrosomia
- Shoulder dystocia and birth trauma
- Fetal compromise, fetal distress and sudden fetal death are more common and related to poor control in the third trimester
This has implications for birth, mainly posing a risk of shoulder dystocia. Longer-term, women are at higher risk of developing type 2 diabetes after pregnancy
- UTI, wound and endometrial infection more common
- Pre-existing hypertension found in 25% of overt diabetics
- PET more common
- IHD worsens
- CS or instrumental delivery more likely due to fetal compromise and increased fetal size
What are the RFs for gestational diabetes? What should we do for women with any RF?
- Previous gestational diabetes
- Previous macrosomic baby (≥ 4.5kg)
- BMI > 30
- Ethnic origin (black Caribbean, Middle Eastern and South Asian)
- Family history of diabetes (first-degree relative)
Anyone with risk factors should be screened with an oral glucose tolerance test at 24 – 28 weeks gestation. Women with previous gestational diabetes also have an OGTT soon after the booking clinic.
How do we diagnose gestational diabetes?
OGTT
What other features would warrant an OGTT?
- Large for dates fetus
- Polyhydramnios (increased amniotic fluid)
- Glucose on urine dipstick
How should the OGTT be conducted? How do we interpret the results?
An OGTT should be performed in the morning after a fast (they can drink plain water). The patient drinks a 75g glucose drink at the start of the test. The blood sugar level is measured before the sugar drink (fasting) and then at 2 hours.
Normal results are:
- Fasting: < 5.6 mmol/l
- At 2 hours: < 7.8 mmol/l
Results higher than these values are used to diagnose gestational diabetes.
TIP: It is really easy to remember the cutoff for gestational diabetes as simply 5 – 6 – 7 – 8.
How should we manage gestational diabetes antenatally?
- Patients with gestational diabetes are managed in joint diabetes and antenatal clinics, with input from a dietician - Offer review within 1 week - clinics should be in contact with women every 1 to 2 weeks throughout the pregnancy.
- Women need careful explanation about the condition, and to learn how to monitor and track their blood sugar levels.
- They need four weekly ultrasound scans to monitor the fetal growth and amniotic fluid volume from 28 to 36 weeks gestation.
The initial management suggested by the NICE guidelines (2015) is:
- Fasting glucose less than 7 mmol/l: trial of diet and exercise
- Change to low glycemic index foods
- Refer to dietician
- Regular exercise (e.g. walking for 30 minutes after a meal)
- If targets are not met by diet and exercise after 1-2 weeks: start metformin
- if metformin contraindicated, go straight to insulin
- if diet, exercise and metformin ineffective - add insulin
- Can also try Glibenclamide if insulin therapy is declined
- Fasting glucose above 6 mmol/l plus macrosomia (or other complications) or fasting glucose above 7 mmol/l: start insulin ± metformin
Glibenclamide (a sulfonylurea) is suggested as an option for women who decline insulin or cannot tolerate metformin.
Monitoring:
- T2DM or gestational diabetes on a multiple daily insulin injection regimen: fasting, pre-meal, 1-hour post-meal and bedtime blood glucose
- T2DM or gestational diabetes managing their diabetes with diet and exercise changes alone/oral therapy/single dose insulin: fasting and 1-hour post-meal glucose
• Pre-prandial target = <5.3 mmol/l, 1hr post-prandial target = <7.8 mmol/l
• Intrapartum
o Organise elective birth for no later than 40+6 weeks gestation.
How should you manage gestational diabetes post-natally?
o Discontinue blood glucose lowering treatment immediately after delivery
o Monitoring
Fasting blood glucose at 6-13 weeks postnatal (or HbA1c if after 13 weeks) to exclude new diagnosis of diabetes
If <6.0 mmol/L = moderate risk of developing T2DM, offer annual HbA1c and diet and lifestyle advice
If 6.0-6.9 mmol/L = high risk of developing T2DM, offer annual HbA1c and diet and lifestyle advice
If >7.0 mmol/L = likely to have T2DM at present, offer diagnostic test to confirm
o Future pregnancies
Offer early OGTT in subsequent pregnancies (as soon as possible after booking, and again at 24-28 weeks gestation if the results of the first screening are normal)
What are babies of mothers with diabetes at risk of? What do we do about this?
- Neonatal hypoglycaemia
- Polycythaemia (raised haemoglobin)
- Jaundice (raised bilirubin)
- Congenital heart disease
- Cardiomyopathy
Babies need close monitoring for neonatal hypoglycaemia, with regular blood glucose checks and frequent feeds. The aim is to maintain their blood sugar above 2 mmol/l, and if it falls below this, they may need IV dextrose of nasogastric feeding.
TOM TIP: If you remember two complications of gestational diabetes, remember macrosomia and neonatal hypoglycaemia. Babies become accustomed to a large supply of glucose during the pregnancy, and after birth they struggle to maintain the supply they are used to with oral feeding alone.
How should a woman be counselled on gestational diabetes?
What are the three main causes of antepartum haemorrhage?
The three causes of antepartum haemorrhage to remember are placenta praevia, placental abruption and vasa praevia.
What are the causes of spotting or minor bleeding?
Causes of spotting or minor bleeding in pregnancy include cervical ectropion, infection and vaginal abrasions from intercourse or procedures.
What is the difference between a low-lying placenta and a placenta praevia?
(apply after 16 weeks)
- Low-lying placenta is used when the placenta is within 20mm of the internal cervical os
- Placenta praevia is used only when the placenta is over the internal cervical os
How common is placenta praevia?
1% of pregnancies
What are the risks of having placenta praevia?
Placenta praevia is associated with increased morbidity and mortality for the mother and fetus. The risks include:
- Antepartum haemorrhage
- Emergency caesarean section
- Emergency hysterectomy
- Maternal anaemia and transfusions
- Preterm birth and low birth weight
- Stillbirth
How do we grade placenta praevia?
- Grade I or minor praevia is defined as a lower edge inside the lower uterine segment
- Grade II or marginal praevia as a lower edge reaching the internal os
- Grade III or partial praevia when the placenta partially covers the cervix
- Grade IV or complete praevia when the placenta completely covers the cervix.
Grades I and II are also often defined as ‘minor’ placenta praevia whereas grades III and IV are referred to as ‘major’ placenta praevia.
What are the RFs for placenta praevia?
The risk factors for placenta praevia are:
- Previous caesarean sections
- Previous placenta praevia
- Older maternal age
- Maternal smoking
- Structural uterine abnormalities (e.g. fibroids)
- Assisted reproduction (e.g. IVF)
What is the clinical presentation of placenta praevia?
The 20-week anomaly scan is used to assess the position of the placenta and diagnose placenta praevia - could be aymptomatic
Many women with placenta praevia are asymptomatic. It may present with painless vaginal bleeding in pregnancy (antepartum haemorrhage). Bleeding usually occurs later in pregnancy (around or after 36 weeks).
How do we manage placenta praevia if identified at 20 weeks?
For women with a low-lying placenta or placenta praevia diagnosed early in pregnancy (e.g. at the 20-week anomaly scan), the RCOG guideline (2018) recommends a repeat transvaginal ultrasound scan at:
- 32 weeks gestation including a TVS → rescan at 36 weeks
- 36 weeks gestation → recommend elective C-section at 36-37 weeks gestation (i.e. before allowing for spontaneous labour to occur)
Corticosteroids are given between 34 and 35 + 6 weeks gestation to mature the fetal lungs, given the risk of preterm delivery.
Planned delivery is considered between 36 and 37 weeks gestation. It is planned early to reduce the risk of spontaneous labour and bleeding.
Planned cesarean section is required with placenta praevia and low-lying placenta (<20mm from the internal os).
Depending on the position of the placenta and fetus, different incisions may be made in the skin and uterus, for example, vertical incisions. Ultrasound may be around the time of the procedure to locate the placenta.
How do we manage placenta praevia with active bleeding?
- ABCDE approach
- Gain IV access
- Bloods (FBC, Rhesus status, cross-match, clotting screen)
- Continuous foetal monitoring
- Give anti-D immunoglobulin in Rh-negative women
- Decide on delivery: If mother is haemodynamically unstable or there is evidence of foetal distress → Expedite delivery (irrespective of gestation)
- If mother is haemodynamically stable, with no evidence of foetal distress → Give steroids and admit until bleeding has stopped (and for a further 48 hours for observation)
- Re-scan at 36 weeks - If still low-lying/praevia → recommend elective C-section at 34- 36 weeks gestation
What are the main complications of placenta praevia?
The main complication of placenta praevia is haemorrhage before, during and after delivery. When this occurs, urgent management is required and may involve:
- Emergency caesarean section
- Blood transfusions
- Intrauterine balloon tamponade
- Uterine artery occlusion
- Emergency hysterectomy
How does cervical length aid our decision in managing placenta praevia?
Cervical length measurement may help facilitate management decisions in asymptomatic women with placenta praevia. A short cervical length on TVS before 34 weeks of gestation increases the risk of preterm emergency delivery and massive haemorrhage at caesarean section
In what situations is vaginal delivery appropriate for women with a low-lying placenta?
In women with a third trimester asymptomatic low-lying placenta the mode of delivery should be based on the clinical background, the woman’s preferences, and supplemented by ultrasound findings, including the distance between the placental edge and the fetal head position relative to the leading edge of the placenta on TVS.
How common is obstetric haemorrhage?
Obstetric haemorrhage remains one of the major causes of maternal death in developing countries and is the cause of up to 50% of the estimated 500 000 maternal deaths that occur globally each yea
Define vasa praevia.
Vasa praevia is a condition where the fetal vessels are within the fetal membranes (chorioamniotic membranes) and travel across the internal cervical os. The fetal membranes surround the amniotic cavity and developing fetus.
What do the foetal vessels consist of?
The fetal vessels consist of the two umbilical arteries and single umbilical vein.
Where are the foetal vessels usually found?
Under normal circumstances, the umbilical cord containing the fetal vessels (umbilical arteries and vein) inserts directly into the placenta. The fetal vessels are always protected, either by the umbilical cord or by the placenta. The umbilical cord contains Wharton’s jelly. Wharton’s jelly is a layer of soft connective tissue that surrounds the blood vessels in the umbilical cord, offering protection.
In what instances are the foetal vessels exposed?
There are two instances when the fetal vessels can be exposed, outside the protection of the umbilical cord or placenta:
- Velamentous umbilical cord is where the umbilical cord inserts into the chorioamniotic membranes, and the fetal vessels travel unprotected through the membranes before joining the placenta.
- An accessory lobe of the placenta (also known as a succenturiate lobe) is connected by fetal vessels that travel through the chorioamniotic membranes between the placental lobes.
What is the pathophysiology of vasa praevia?
In vasa praevia, the fetal vessels are exposed, outside the protection of the umbilical cord or the placenta. The fetal vessels travel through the chorioamniotic membranes, and pass across the internal cervical os (the inner opening of the cervix). These exposed vessels are prone to bleeding, particularly when the membranes are ruptured during labour and at birth. This can lead to dramatic fetal blood loss and death.
What are the 2 types of vasa praevia?
There are two types of vasa praevia:
- Type I vasa praevia – the fetal vessels are exposed as a velamentous umbilical cord
- Type II vasa praevia – the fetal vessels are exposed as they travel to an accessory placental lobe
What are the RFs for vasa praevia?
- Low lying placenta
- IVF for pregnancy
- Multiple pregnancy
How does vasa praevia present?
- Asymptomatic - Vasa praevia may be diagnosed by ultrasound during pregnancy. This is the ideal scenario, as it allows a planned caesarean section to reduce the risk of haemorrhage. However, ultrasound is not reliable, and it is often not possible to diagnose antenatally.
- It may present with antepartum haemorrhage, with bleeding during the second or third trimester of pregnancy.
- It may be detected by vaginal examination during labour, when pulsating fetal vessels are seen in the membranes through the dilated cervix.
- Finally, it may be detected during labour when fetal distress and dark-red bleeding occur following rupture of the membranes. This carries a very high fetal mortality, even with emergency caesarean section.
How should we manage vasa praevia when antenatally diagnosed?
For asymptomatic women with vasa praevia, the RCOG guidelines (2018) recommend:
- A decision for prophylactic hospitalisation from 30–32 weeks of gestation in women with confirmed vasa praevia should be individualised and based on a combination of factors, including multiple pregnancy, antenatal bleeding and threatened premature labour
- Corticosteroids, given from 32 weeks gestation to mature the fetal lungs
- Elective caesarean section, planned for 34 – 36 weeks gestation (prior to onset of labour)
How should we manage undiagnosed vasa praevia at delivery?
Emergency caesarean delivery and neonatal resuscitation, including the use of blood transfusion if required, are essential in the management of ruptured vasa praevia diagnosed during labour.
Placental pathological examination should be performed to confirm the diagnosis of vasa praevia, in particular when stillbirth has occurred or where there has been acute fetal compromise during delivery.
Define multiple pregnancy
Multiple pregnancy refers to a pregnancy with more than one fetus.
Lambda sign → Dichorionic diamniotic pregnancy
T sign → Monochorionic diamniotic
Monochorionic monoamniotic
Describe the pathophysiology of pre-eclampsia.
- When the blastocyst implants on the endometrium, the outermost layer, called the syncytiotrophoblast, grows into the endometrium.
- It forms finger-like projections called chorionic villi. The chorionic villi contain fetal blood vessels.
- Trophoblast invasion of the endometrium sends signals to the spiral arteries in that area of the endometrium, reducing their vascular resistance and making them more fragile.
- The blood flow to these arteries increases, and eventually they break down, leaving pools of blood called lacunae (lakes).
- Maternal blood flows from the uterine arteries, into these lacunae, and back out through the uterine veins. Lacunae form at around 20 weeks gestation.
- When the process of forming lacunae is inadequate, the woman can develop pre-eclampsia.
- Pre-eclampsia is caused by high vascular resistance in the spiral arteries and poor perfusion of the placenta.
- This causes oxidative stress in the placenta, and the release of inflammatory chemicals into the systemic circulation, leading to systemic inflammation and impaired endothelial function in the blood vessels.
How do we manage gestational hypertension antenatally?
Consider labetalol to treat gestational hypertension. Consider nifedipine[3]for women in whom labetalol is not suitable, and methyldopa if labetalol or nifedipine[3] are not suitable. Base the choice on side-effect profiles, risk (including fetal effects) and the woman’s preferences
How is pre-eclampsia antenatally?
- Offer labetalol to treat hypertension in pregnant women with pre-eclampsia.
- Offer nifedipine for women in whom labetalol is not suitable, and
- methyldopa if labetalol or nifedipine are not suitable.
- Base the choice on any pre-existing treatment, side-effect profiles, risks (including fetal effects) and the woman’s preference.
How should we counsel a woman on pre-eclampsia?
