1st Trimester Conditions

Hyperemesis Gravidarum

This is a condition which causes nausea and vomiting in pregnant women and accompanied with weight loss

– Nausea and vomiting is common during pregnancy, and so the term hyperemesis gravidarum is only used if this leads to complications like dehydration or >5% weight loss

– This condition is experiences in the first trimester and usually resolves by week 20

– It is believed to be due to raised beta-hCG sensitizing the vomiting centre

– Severe vomiting leads to dehydration and electrolyte abnormalities in the mother

Risk factors:

This is anything which leads to raised b-hCG

– Factors which raised b-hCG –> Multiple pregnancies (twins), Gestational trophoblastic disease

– Hyperthyroidism –> TSH is similar to b-hCG

– Obesity

Symptoms:

– Severe nausea and vomiting accompanied with weight loss

Complications:

– Mechanical –> Mallory-Weiss tear of the oesophagus

– Neurological –> Wernicke’s encephalopathy, central pontine myelinosis

– Renal –> acute tubular necrosis, AKI due to hypovolaemia

– Foetal –> Preterm birth and intrauterine growth restriction

Diagnosis:

– In addition to the nausea and vomiting, you need additional features such as:

– Weight loss of 5% pre-pregnancy weight

– Dehydration

– Electrolyte disturbances

Management:

– Check urine for ketones –> if raised, then admit patient

– Anti-emetics –> 1st is Promethazine or Cyclizine –> 2nd line is ondansetron/metoclopramide

– Fluids (Hartmann’s solution) for rehydration with Vitamin B1 replacement

– Prophylactic Dalteparin –> dehydrated patients at a high risk of venous thromboembolism

– If unresolving, you can give IV hydrocortisone

– Last resort is a termination of pregnancy

Ovarian Hyper-Stimulation Syndrome (OHSS)

This is a complication of IVF treatment which occurs after excessive stimulation of the ovary

– IVF treatment results in multiple corpus luteum cysts in the ovary which lead to high levels of oestrogen, progesterone and vasoactive chemicals like VEGF

– This causes increased angiogenesis and higher vascular permeability leading to oedema

Risk factors:

– IVF treatment with GnRH or hCG treatment

Symptoms:

– Oedema –> pitting oedema, ascites and pulmonary oedema (giving breathlessness)

– Abdominal pain and bloating

– Dehydration –> high risk of venous thromboembolism

– AKI –> due to the physical pressure on the kidneys

Tests:

– Measure abdominal girth (used to assess severity of ascites)

– Blood tests –> shows hypoproteinaemia and haematocrit > 45%

Management:

– Only symptomatic control is possible

– Prophylactic dalteparin –> reduces risk of thromboembolisms

– Analgesia and titrate fluid balance to reduce fluid shifting into the interstitial space

Prevention:

– During IVF do single embryo transfer to stop OHSS (also reduces multiple pregnancies)

– You can also give metformin or cabergoline to help reduce release of vasoactive substances like VEGF

Gestational Trophoblastic diseases (GTD)

This is a group of pregnancy related tumours which originate from the placenta trophoblast cells.

– These tumours result in very high levels of serum b-hCG which can cause hyperemesis and hyperthyroidism (as b-HSH mimics TSH stimulating the thyroid gland)

Risk factors:

– Maternal age (<20 or >35)

– Use of COCP

– Previous history of GTD

The GTDs can be split into pre-malignant tumours (more common) and malignant tumours:

Pre-Malignant Conditions (more common)

These tumours are benign but can become malignant, invade myometrium and spread to rest of the body

Partial molar pregnancy

This is a situation in which a single ovum is fertilised by 2 sperm cells

– This produces a cell which exhibits triploidy, with a total of 69 chromosomes

– A partial mole may exist with a viable fetus if mosaicism is present (i.e. if the fetus has a normal karyotype and the triploidy is confined to the placenta)

Complete molar pregnancy:

This is a situation in which one ovum without any chromosomes is fertilised by either one sperm that duplicates (more common) or two different sperm

– This produces a cell with a total of 46 chromosomes of paternal origin alone

– Shows granular/snowstorm appearance with central heterogenous mass surrounding many cystic area/vesicles on ultrasound 

Malignant Conditions (Rarer)

Invasive Moles

This is partial/molar pregnancy which has become malignant 

Choriocarcinoma

This is a malignant proliferation of trophoblastic cells of the placenta

– It commonly co-exists with a molar pregnancy and metastasises to the lungs

Symptoms:

In early pregnancy:

– Vaginal bleeding and abdominal pain

– Soft, boggy uterus that is larger than expected for gestation

– Hyperemesis (very high levels of serum b-hCG)

In 2nd/3rd trimesters:

– Hyperthyroidism (heat intolerance, weight loss, hypertension) as b-hCG mimics TSH

– “Large for dates” uterus

Key Tests:

– b-HCG –> very high

– Ultrasound –> this shows an abnormally enlarged uterus which is large for dates

– Histology –> Performed on the products of conception following their passage to confirm the diagnosis

Management:

– This needs urgent referral as the pregnancy is non-viable and needs to be removed

– For molar pregnancies –> suction curettage or medical evacuation of the uterus

– It is recommended to avoid becoming pregnant again in the following 12 months