Hyperemesis Gravidarum: A Review
Saria Tasnim 1 , Abdul Halim 2

Nausea and vomiting commonly labeled as "morning sickness” are common symptoms of pregnancy. They can appear within two weeks after a missed period, usually diminish by the 14 th week in up to 50% of pregnant women. If it begins after twelve weeks of gestation there may be a medical or surgical cause. If vomiting is of such intensity that it interferes with normal activity it is pathological1.

Causes of vomiting in pregnancy
Early pregnancy

»     Morning sickness
»     Hyperemesis gravidarum
»     Associated causes
Late pregnancy
»     Severe PET
»     Urinary tract infection
»     Acute hydramnios

Hyperemesis gravidarum is defined as excessive vomiting and nausea occuring before 20th week of gestation. The vomiting is intractable, occur irrespective of food and severe enough to require hospitalization.2 It is complicated by weight loss, dehydration, ketonuria sometimes by serious psychological disturbances. Hyperemesis can lead to sever maternal malnutrition and threaten fetal well being.

Epidemiology of Hyperemesis
The condition was described as early as 2000 BC. In a Epidemiological study 70% of all pregnancy were associated with nausea, in 91% of the case the onset was during first three months.3 This has a tendency to recur. It has been found that there was no difference of intensity, peak nausea or time of onset in successive pregnancy, however the duration decrease. There is a strong correlation between nausea and tolerance of oral contraceptives.4 Study have shown that offspring of women hospitalized for hyperemesis have higher proportion of females than do all mothers.5 It is more common in primigravida.

Incidence
Although nausea and vomiting are second most common symptom of pregnancy, the incidence of hyper emesis is 0.3%.6

Causes
It is not clear It appears that hyperemesis has complex interaction of biological, psychological and socio cultural factors.
Associated factors are the following
1. Vitamin B6 deficiency: due to change in protein metabolism.
2. Hyperthyroidism: found in 70% of patients with hyperemesis, Human Chronic Gonadotrophin (hCG) is not directly involved in     the a etiology of hyperemesis but indirectly by its ability to stimulate the thyroid.7
3. Psychopathologic and emotional factors. It has been observed that hyper emesis improves after hospitalization, being away     from home environment.
4. Hyperplacentosis: A condition of heightened trophoblastic activity is characterized by increased placental weight and hCG     level. Hyperplacentosis is regarded to be associated with hyperemesis 8
5. Hypersensitivity reaction.
6. Poor nutrition
7. Sex steroid imbalance - Progesterone deficiency and estrogen excess often implicated and there may be
    adrenal and  pituitary dysfunction. However, evidence shows there is no hypo function of anterior pituitary gland. It has been     found that nausea and vomiting in early pregnancy is associated with lower cortisol and progesterone and high hCG but     vomiting in late pregnancy had lower testosterone and hCG but higher dehydroepiandosterone.
4

8. Other factors proposed are tissue polypeptide anigen, high LDL and VLDL, low HDL, gall bladder disease and ovulation from     right ovary 4.

Patho physiology
Pregnancy is associated with gut disturbances. These include delayed gastric emptying ,reduced esophageal sphincter pressure, decreased gall bladder motility with increased gut transit times. The changes result from inhibitory action of progesterone on the gut which contribute to vomiting. However it is difficult to reconcile the decline of pregnancy sickness after first trimester and the increase of progesterone.
6

Clinical Feature
There is inability to retain food and fluid
»     Intractable vomiting
»     Dehydration
»     Dry and coated tongue
»     Skin turgor decrease
»     Acetone breath and ketonuria
»     Significant weight loss
»     Jaundice and various palsy may supervene
»     Metabolic acidosis

If weight loss greater than 5% of pre pregnant weight of the patient it is associated with poor fetal growth and out come.

Biochemical
»     Plasma Na K     CI  
»     Urea
»     Hypokalaemia
»     Alkalosis
»     Urine volumemay contain albumin and bile, chloride is absent

Pathology
The changes are generalized manifestation of starvation and severe malnutrition
»     Liver: Centrilobular fatty infiltration
»     Kidney: Fatty change in proximal convuluted tubule
»     Heart: Subendocardial hemorrahge
»     Brain: Small hemorrhage in hypothalamic area
»     Wernick's encephalopathy (apathy, restlessness, sleeplessness, convulsion and coma)
»     Korsakoff psychosis: (Confusion, loss of memory)


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1. Dr. Saria Tasnim,
MBBS, FCPS (Gyn & Obs )
    Senior Consultant (Obs & gyn), Institute of Child and Mother Health Matuail, Dhaka.
2. Dr. Abdul Halim, MBBS, FCPS (Gyn & Obs )
    Assistant Professor (Gyn & Obs ), Institute of Child and Mother Health Matuail, Dhaka
.