Nausea and vomiting in pregnancy

Obstetrics

Family practice, obstetric triage or the emergency department, usually before 16 weeks

The first question

Is this the nausea of pregnancy, and is she keeping enough down to stay hydrated?

Two patients: the gestational age and the maternal stability first, then the fetal status.

01
Severity
Frequency of vomiting, what stays down, weight compared with pre-pregnancy, and the ability to work and care for others. Hyperemesis is the severe end: dehydration, weight loss over 5 percent and electrolyte disturbance.
02
Dating and the pregnancy
Confirm the gestation and that the pregnancy is intrauterine; nausea that starts after 10 weeks or persists past 20 is unusual for the pregnancy alone.
03
Other causes
Fever, abdominal pain, headache, dysuria, diarrhoea, a new medication or a thyroid story point away from simple nausea of pregnancy.
04
Treat in steps
Diet and lifestyle, then pyridoxine with doxylamine, then a second-line antiemetic; fluids and thiamine before glucose when admitted; treat reflux and constipation, which worsen it.
05
Safety-net
Return for inability to keep fluids down for 24 hours, dark urine, dizziness on standing, blood in the vomit or abdominal pain.

Where it is

Each opens the structure on the 3D pelvis.

Onset relative to the last period, frequency of vomiting and what stays down
Weight before pregnancy and now
Urine output and colour, dizziness on standing
Abdominal pain, fever, headache, diarrhoea, urinary symptoms
Previous pregnancies with the same, and how they were treated
Medications, including iron, and supplements
Thyroid symptoms, and a multiple or molar pregnancy if the uterus feels large
Mood, sleep and support: the symptom that keeps people off work and out of relationships

Urinalysis for ketones and infection
Electrolytes, creatinine and urea; liver enzymes and lipase in the severe or atypical case
Thyroid function when severe (a suppressed TSH from hCG is common and settles; overt thyrotoxicosis has a goitre or eye signs)
Ultrasound to confirm an intrauterine pregnancy and to look for twins or a molar pregnancy
The PUQE score to grade severity and to track treatment

Diagnosis	Favours	Against	Urgency
Nausea and vomiting of pregnancy	Onset by 6 to 8 weeks, worst around 9 to 10, no fever or abdominal pain, keeping some fluids down	Onset after 10 weeks, fever, abdominal pain, neurological symptoms	routine
Hyperemesis gravidarum	Persistent vomiting with weight loss over 5 percent, dehydration, ketonuria and electrolyte disturbance	Weight maintained, no ketones, working and eating	urgent
Urinary tract infection or pyelonephritis	Dysuria, frequency, loin pain, fever, nitrites and leucocytes	Clean dipstick, no fever	urgent
Molar or multiple pregnancy	Uterus large for dates, very high hCG, severe early symptoms, bleeding	Single intrauterine pregnancy of the right size on scan	urgent
Thyrotoxicosis	Goitre, eye signs, tremor, heat intolerance, symptoms before the pregnancy	A suppressed TSH alone in the first trimester, which is hCG and settles	routine
Gastrointestinal or surgical cause	Abdominal pain, fever, diarrhoea, a raised lipase or liver enzymes	No pain, normal bloods	urgent

Pitfalls this pathway refuses

Calling it morning sickness and sending home a patient with ketones and a postural drop
Giving glucose-containing fluids before thiamine in the malnourished
Treating a suppressed TSH in the first trimester as thyroid disease
Not asking about the effect on mood, work and the family
Starting antiemetics late because they were assumed unsafe: the first-line agents are well studied in pregnancy