Hyperemesis_Gravidarum_Flashcards
What is hyperemesis gravidarum and its prevalence?
Hyperemesis gravidarum is the extreme form of nausea and vomiting in pregnancy (NVP), affecting about 1% of pregnancies. It is commonly associated with high beta hCG levels and usually occurs between 8 and 12 weeks of pregnancy.
What are the risk factors for hyperemesis gravidarum?
Risk factors include increased levels of beta-hCG, multiple pregnancies, trophoblastic disease, nulliparity, obesity, and a family or personal history of NVP. Smoking is associated with a decreased incidence.
What are the referral criteria for severe nausea and vomiting in pregnancy?
Referral or admission is considered if the patient cannot keep down liquids or oral antiemetics, continues to lose weight, shows signs of dehydration, or has any comorbidity affected by the nausea.
What is the diagnostic criteria for hyperemesis gravidarum recommended by RCOG?
The RCOG criteria for diagnosing hyperemesis gravidarum include pre-pregnancy weight loss of 5%, dehydration, and electrolyte imbalance.
How is hyperemesis gravidarum managed?
Management includes rest, avoiding triggers, eating bland foods, and using acupressure. Medications include antihistamines like cyclizine or promethazine, phenothiazines like prochlorperazine, and possibly ondansetron or metoclopramide with precautions.
What are potential complications of hyperemesis gravidarum?
Complications can include dehydration, weight loss, electrolyte imbalances, acute kidney injury, Wernicke’s encephalopathy, oesophagitis, Mallory-Weiss tear, and venous thromboembolism.
How does severe NVP affect fetal outcomes?
While mild to moderate NVP generally shows little risk of adverse fetal outcomes, severe NVP leading to multiple hospital admissions may increase the risk of preterm birth and low birth weight.
summarise
Hyperemesis gravidarum
Whilst the majority of women experience nausea (previously termed ‘morning sickness’) during the early stages of pregnancy it can become problematic in a minority of cases. The Royal College of Obstetricians and Gynaecologists (RCOG) now use the term ‘nausea and vomiting of pregnancy’ (NVP) to describe troublesome symptoms, with hyperemesis gravidarum being the extreme form of this condition.
It occurs in around 1% of pregnancies and is thought to be related to raised beta hCG levels. Hyperemesis gravidarum is most common between 8 and 12 weeks but may persist up to 20 weeks.
Risk factors
increased levels of beta-hCG
multiple pregnancies
trophoblastic disease
nulliparity
obesity
family or personal history of NVP
Smoking is associated with a decreased incidence of hyperemesis.
Referral criteria for nausea and vomiting in pregnancy
NICE Clinical Knowledge Summaries recommend considering admission in the following situations: CKS
Continued nausea and vomiting and is unable to keep down liquids or oral antiemetics
Continued nausea and vomiting with ketonuria and/or weight loss (greater than 5% of body weight), despite treatment with oral antiemetics
A confirmed or suspected comorbidity (for example she is unable to tolerate oral antibiotics for a urinary tract infection)
They also recommend having a lower threshold for admission to hospital if the woman has a co-existing condition (for example diabetes) that may be adversely affected by nausea and vomiting.
Hyperemesis gravidarum
The Royal College of Obstetricians and Gynaecologists (RCOG) recommend that the following triad is present before diagnosis of hyperemesis gravidarum: RCOG
5% pre-pregnancy weight loss
dehydration
electrolyte imbalance
Validated scoring systems such as the Pregnancy-Unique Quantification of Emesis (PUQE) score can be used to classify the severity of NVP.
Management
simple measures
rest and avoid triggers e.g. odours
bland, plain food, particularly in the morning
ginger
P6 (wrist) acupressure
first-line medications CKS
antihistamines: oral cyclizine or promethazine
phenothiazines: oral prochlorperazine or chlorpromazine
combination drug doxylamine/pyridoxine: pyridoxine (vitamin B6) monotherapy is actually used commonly outside of the UK as a first-line treatment for NVP. However, pyridoxine monotherapy is specifically not recommended in the RCOG guidelines
second-line medications
oral ondansetron: ondansetron during the first trimester is associated with a small increased risk of the baby having a cleft lip/palate. The Medicines and Healthcare products Regulatory Agency (MHRA) advise that if ondansetron is used then these risks should be discussed with the pregnant woman
oral metoclopramide or domperidone: metoclopramide may cause extrapyramidal side effects. It should therefore not be used for more than 5 days
admission may be needed for IV hydration
see criteria above for referral/admission
normal saline with added potassium is used to rehydrate
Women with hyperemesis gravidarum may develop dehydration, weight loss and electrolyte imbalances. Other complications include:
acute kidney injury
Wernicke’s encephalopathy
oesophagitis, Mallory-Weiss tear
venous thromboembolism
fetal outcome CKS
studies generally show little evidence of adverse outcomes for birth weight/other markers for mild-moderate symptoms
severe NVP resulting in multiple admissions and failure to ‘catch-up’ weight gain may be linked to a small increase in preterm birth and low birth weight
A 30-year-old woman (G2P1), currently 10 weeks pregnant, has been struggling with vomiting during her pregnancy. On examination, she is clinically dehydrated. At the start of her pregnancy, she weighed 60kg and currently weighs 56kg. Her blood tests show some electrolyte abnormalities.
What is a risk factor for this condition?
Low BMI
Multiparity
Singleton pregnancy
Smoking
Trophoblastic disease
Trophoblastic disease
Trophoblastic disease is a risk factor for hyperemesis gravidarum
This patient is presenting with the characteristic triad of hyperemesis gravidarum: ≥ 5% pre-pregnancy weight loss, dehydration and electrolyte imbalance.
Trophoblastic disease is the correct answer. Trophoblastic disease (molar pregnancy) is a risk factor for hyperemesis gravidarum due to the increased levels of beta-HCG.
Low BMI is incorrect. Obesity is a risk factor for hyperemesis gravidarum.
Multiparity is incorrect. Nulliparity (first pregnancy) is a risk factor for hyperemesis gravidarum.
Singleton pregnancy is incorrect. Multiple pregnancy is a risk factor for hyperemesis gravidarum.
Smoking is incorrect. Smoking is associated with a decreased incidence of hyperemesis gravidarum.
A 33-year-old woman has recently had a positive pregnancy test. She attends the emergency department as she has been vomiting profusely over the last 5 days and is unable to keep fluids down. On examination, she appears clinically dehydrated and reports a weight loss of 7% from her pre-pregnancy weight.
Some of her blood results are shown below:
Na+ 130 mmol/L (135 - 145)
K+ 3.2 mmol/L (3.5 - 5.0)
What is a risk factor for the most likely diagnosis in this case?
Age >30
Multiparity
Singleton pregnancy
Smoking
Trophoblastic disease
Trophoblastic disease
Trophoblastic disease is a risk factor for hyperemesis gravidarum
The most likely diagnosis in this scenario is hyperemesis gravidarum. Diagnosis of hyperemesis gravidarum is determined by the presence of 5% (or greater) pre-pregnancy weight loss, dehydration and electrolyte imbalance - all of which are present in this scenario. Hyperemesis gravidarum refers to the most severe form of nausea and vomiting during pregnancy, typically occurring between weeks 8 and 12 of gestation, though it may present up to week 20. Risk factors for hyperemesis gravidarum include a family history of the condition, multiple pregnancies, or trophoblastic disease.
Trophoblastic disease is correct. Trophoblastic disease describes the growth of abnormal trophoblast cells in the uterus after conception, rather than the development of a healthy fetus. Although the aetiology is unclear, trophoblastic disease constitutes a risk factor for hyperemesis gravidarum and therefore this is the correct answer.
Age > 30 is incorrect. Being over the age of 30 does not constitute a risk factor for hyperemesis gravidarum.
Multiparity is incorrect. It is nulliparity—having no previous pregnancies—that poses a risk for hyperemesis gravidarum rather than multiparity. However, having multiple pregnancies (e.g., twins) does heighten the risk.
Singleton pregnancy is incorrect. It is multiple pregnancies (e.g., twins) which increase the risk of developing hyperemesis gravidarum.
Smoking is incorrect. Research indicates that smoking before and during pregnancy may exert a protective effect against developing hyperemesis gravidarum. Despite this association, smoking during pregnancy is strongly discouraged. Pregnant women should receive advice and support to cease smoking due to its overall risks to both maternal and fetal health.
A woman in her 11th week of pregnancy presents to the emergency department with a one-week history of severe vomiting and loss of appetite. The smell of food makes her nauseous. She has not eaten anything for the last three days and has only drunk small amounts of water.
Current medications include omeprazole and folic acid. She is teetotal and has never smoked.
Which of the following is an example of a risk factor for this condition?
Corticosteroids
Increased maternal age
Multiparity
Multiple pregnancies
Smoking
Multiple pregnancies
Multiple pregnancy is a risk factor for hyperemesis gravidarum
Multiple pregnancies is the only risk factor listed above for hyperemesis gravidarum (HG). Other risk factors include obesity, epilepsy, stress and positive family history.
Corticosteroids such as prednisolone may be used to treat hyperemesis gravidarum. Other medications may include anti-emetic drugs such as ondansetron as well as vitamins B6 and B12.
Increased maternal age increases the risk of pregnancy-induced hypertension, pre-eclampsia, gestational diabetes and Down’s syndrome, but has not been shown to increase the risk of developing HG during pregnancy.
Multiparity has not been shown to increase the risk of developing hyperemesis gravidarum, although the previous history of hyperemesis gravidarum in a previous pregnancy may be a risk factor.
Smoking before and/or during pregnancy does not increase the risk of hyperemesis gravidarum. Studies have shown that smoking may reduce the risk of developing hyperemesis gravidarum.
buzz words
first trimester
vomiting during her pregnancy.
clinically dehydrated.
electrolyte abnormalities. (low sodium, low potassium)
unable to keep fluids down.
weight loss from her pre-pregnancy weight.
You receive a call from a 26-year-old woman who is 9-weeks pregnant with twins. Last week she had severe nausea and vomiting despite a combination of oral cyclizine and promethazine. She continued to vomit and was admitted to the hospital briefly where she was started on metoclopramide and ondansetron which helped control her symptoms.
Today she tells you she read a pregnancy forum article warning about ondansetron use in pregnancy. She is worried and wants advice if she should continue taking it.
How should you counsel this woman on the risks of ondansetron use in pregnancy?
There are no recognised risks for her, the pregnancy or the newborns
There is a small but significant risk of spontaneous miscarriage in twin pregnancies
There is a small increased risk of cleft lip/palate in the newborn if used in the first trimester
There is an established risk of severe congenital heart defects in the newborn and it should be stopped
There is some evidence of an increased rate of developing HELLP syndrome in the 3rd trimester
There is a small increased risk of cleft lip/palate in the newborn if used in the first trimester
Ondansetron during pregnancy is associated with a small increased risk of cleft palate/lip - the MHRA advise that these risks need to be discussed with the pregnant woman before use
The correct answer is there is an association with a small increased risk of cleft lip/palate in the newborn if used in the first trimester. The Medicines and Healthcare products Regulatory Agency (MHRA) issued a drug safety update regarding ondansetron use in the first 12 weeks of pregnancy being associated with a small but significant increased risk of orofacial cleft malformations.
The MHRA statement comments on the evidence:
‘…This was based on an observational study of 1.8 million pregnancies in the US of which 88,467 (4.9%) were exposed to oral ondansetron during the first trimester of pregnancy. The study reported that ondansetron use was associated with an additional 3 oral clefts per 10,000 births (14 cases per 10,000 births versus 11 cases per 10,000 births in the unexposed population)’.
This risk is discussed but not included in the Royal College of Gynaecology (RCOG) guideline on the management of nausea and vomiting of pregnancy (2016). There is no official NICE guidance on nausea and vomiting during pregnancy, however, a draft has been published as of August 2021, as part of an update to NICE’s antenatal care guidance. This suggests the following on the use of ondansetron:
‘Increased chance of the baby being born with a cleft lip or cleft palate. This is an increase of 3 extra cases per 10,000 from 11 in 10,000 to 14 in 10,000, so with ondansetron 9,986 out of 10,000 babies would not have this. Some evidence suggests ondansetron may cause heart problems in babies but other evidence does not support this.
There are no recognised risks for her, the pregnancy or the newborn is not correct. It does not address the MHRA’s recommendation of the above small but significant risks of cleft lip and palate.
There is a small but significant risk of spontaneous miscarriage in twin pregnancies is not correct. This is a fictitious risk contrived for this question.
There is an established risk of severe congenital heart defects in the newborn and it should be stopped is not correct. Whilst there has been some evidence from some studies about a small risk, both the RCOG’s guideline (2016) and NICE guidance (2021) suggest this is not an established risk. The MHRA statement (2020) advises similarly that the findings conflict with previous evidence of no such risk. Therefore, this option is incorrect as this risk is not established.
There is some evidence of an increased rate of developing HELLP syndrome in the 3rd trimester is not correct. HELLP (haemolysis, elevated liver enzymes, and low platelets) is s a life-threatening complication usually and can be considered a variant of preeclampsia. This usually occurs during the later stages of pregnancy, or soon after childbirth. There is no association between ondansetron use and the development of this syndrome, or pre-eclampsia during pregnancy.
A 33-year-old primigravida attends an antenatal appointment at 9 weeks gestation. She had a private ultrasound a week ago showing dichorionic, diamniotic twins. She has a past medical history of hypothyroidism for which she takes levothyroxine, and has a BMI of 38 kg/m². Although she admits to smoking during her pregnancy, she cut down from 20 to 5 cigarettes/day and is keen to try nicotine replacement therapy. While her pregnancy has been uncomplicated so far, she is concerned as her mother and sister both developed hyperemesis gravidarum.
What factor in this patient’s history is associated with a decreased incidence of developing the same condition as her relatives?
Hypothyroidism
Obesity
Primigravida
Smoking
Twin pregnancy
Smoking
Smoking is associated with a decreased incidence of hyperemesis gravidarum
Hyperemesis gravidarum is believed to occur due to rapidly rising levels of human chorionic gonadotropin (HCG) and oestrogen. Any condition which increases these hormone levels (or is associated with higher hormone levels) will lead to an increased risk of hyperemesis. Smoking is considered to be anti-oestrogenic and has been found to decrease the risk of hyperemesis gravidarum. As this patient is a smoker, this may decrease her incidence of hyperemesis gravidarum despite having other risk factors.
Hypothyroidism is not a risk factor - however, hyperthyroidism increases the risk of a patient having hyperemesis gravidarum. This may be due to hCG and TSH receptor antibodies stimulating the thyroid TSH receptor causing a flare of the symptoms of hyperthyroidism - vomiting.
Obesity (and underweight) is associated with an increased risk of hyperemesis. However, women with obesity or underweight who smoked pre-pregnancy have been found to have no increased risk of hyperemesis.
Primigravida status is associated with an increased risk of hyperemesis - this may be due to the body experiencing high beta-hCG for the first time however there is no clear evidence as to why this occurs.
Twin pregnancies are associated with higher levels of beta-hCG released from the placenta - as such, these carry an increased risk of hyperemesis gravidarum.
A 25-year-old woman at 15 weeks gestation of her first pregnancy returns to her general practitioner with tremor after starting a medication during pregnancy for hyperemesis gravidarum. On examination, the patient has a resting tremor in their left hand and increased upper limb tone.
What medication was the patient most likely prescribed?
Cyclizine
Metoclopramide
Ondansetron
Prednisolone
Promethazine
Metoclopramide is an option for nausea and vomiting in pregnancy, but it should not be used for more than 5 days due to the risk of extrapyramidal effects
This scenario describes a 25-year-old woman who has developed a resting tremor and increased upper limb tone after starting medication for hyperemesis gravidarum. Resting tremor can be part of extrapyramidal effects seen with metoclopramide, particularly when used for longer periods. Due to the risk of extrapyramidal effects, it is recommended that metoclopramide should not be used first-line. But, if it is used, the duration of use should be limited to no more than five days.
Cyclizine is incorrect. Cyclizine is a H1 histamine receptor antagonist, which may be used in hyperemesis gravidarum. Whilst tremor may occur with cyclizine use, the above scenario describes likely extrapyramidal effects, which are not routinely described as a risk. Drowsiness or reduced consciousness should be monitored.
Ondansetron is incorrect. Ondansetron is an anti-emetic that may be used in hyperemesis gravidarum and works by blocking the serotonin receptors in the chemoreceptor trigger zone. Extrapyramidal effects are not described, but common side effects can include constipation and headaches. Some sources recommend that ondansetron should be avoided in the first trimester due to the risk of orofacial clefts.
Prednisolone is incorrect. Corticosteroids are not used first-line in hyperemesis gravidarum, but maybe useful in difficult to manage cases. Corticosteroids have numerous side effects. However, extrapyramidal side effects (such as resting tremors) are not commonly described.
Promethazine is incorrect. Promethazine is an H1 histamine receptor antagonist which can be used in hyperemesis gravidarum. Drowsiness is an important side effect to monitor for.
