Hyperemesis gravidarum (HG) is a rare complication of pregnancy that involves persistent nausea and extreme vomiting to an intensity that distinguishes it from the nausea and vomiting commonly experienced during pregnancy. Research has suggested potential biological and psychological etiologies for Hyperemesis gravidarum, but the augmented prevalence in immigrant populations, which is 45 times higher, remains unclear. Studies show that in order to better address the psychosocial needs of immigrant patients with Hyperemesis gravidarum, we must first improve our understanding of how they experience their illness. The objective of this study was to understand the meaning and experience of Hyperemesis gravidarum among immigrant women in Canada.
Hypermesis gravidarum is a serious complication of pregnancy, presenting as prolonged and severe nausea and vomiting, causing dehydration, malnutrition, and significant morbidity. Women with a history of hypermesis gravidarum have around an 80% chance of suffering in subsequent pregnancies. Careful and thorough planning in advance of a future pregnancy can significantly reduce the overall severity of symptoms and improve the psychosocial welfare of the women, as well as pregnancy outcomes.
Around 80% of pregnant women experience nausea and vomiting to a greater or lesser degree, making it the most common medical condition in pregnancy. Approximately 30% of women are severely affected, while only 1-1.5% of pregnant women are admitted to the hospital with extreme nausea and vomiting, known as hyperemesis gravidarum. According to the Office for National Statistics (ONS) (2013), with 729,674 live births in the UK in 2012, admissions for hyperemesis gravidarum are significant, at nearly 11,000 across the UK. Furthermore, the rate for therapeutic termination for hyperemesis gravidarum is estimated to be 10% in the UK, accounting for further morbidity and admissions. In the financial year of 2003/04, the cost for admission for hyperemesis gravidarum in England was estimated to be £36,481,745. It is the most common reason for hospitalization in early pregnancy and the second most common reason throughout pregnancy, with preterm labor being the first.
Hyperemesis gravidarum is a severe and potentially life-threatening condition that can have a profound effect on the sufferer's health and well-being. Clinical manifestations of Hyperemesis gravidarum include a weight-loss of 5% or more of pre-pregnancy weight, ketosis, and/or a urine output of less than 500 ml in 24 hours. Electrolyte imbalance can occur if left untreated, leading to further complications. Hyperemesis gravidarum is considered an appropriate diagnosis when symptoms are severe and persistent enough to reduce a woman's quality of life, affect her ability to conduct daily activities and prevent her from eating and drinking.
Although some studies indicate a poor relationship between estrogen levels and hyperemesis gravidarum, the role of estrogen in this condition remains unclear. Serum progesterone levels also peak in the first trimester of pregnancy; progesterone alone or in combination with estrogen may cause gastric dysrhythmias by decreasing the contractility of gastric smooth muscles. Serum prostaglandin E2 (PGE2) levels were found to be higher during the symptomatic period of hyperemesis gravidarum. Placental PGE2 synthesis is stimulated by HCG, the latter usually peaking between the 9th and 12th weeks of gestation, which may explain the symptoms of hyperemesis gravidarum. HCG has a thyrotropin action and hyperemesis gravidarum is more common in pregnancies with high HCG.
The thyroid gland is physiologically stimulated during early pregnancy. Sometimes, thyroid hormone values deviate from the normal range, leading to a state referred to as gestational transient thyrotoxicosis (GTT). GTT has been observed in up to two-thirds of women with hyperemesis gravidarum. To study whether GTT and hyperemesis gravidarum are causally related, we examined thyroxine (T4) and TSH levels in hyperemesis gravidarum patients. Of the 15 prospective comparative studies comparing T levels of hyperemesis gravidarum patients with those of asymptomatic controls, eight were matched for gestational age, and eleven showed significantly higher T4 levels in the hyperemesis gravidarum group. Nine out of the thirteen prospective comparative studies investigating TSH levels showed significantly higher TSH levels in the hyperemesis gravidarum group.
Various mechanisms may be involved in the stimulation of thyroid function during pregnancy. Under the influence of estrogens, the production of thyroid-binding globulin increases and T4 metabolism is slowed, causing a transient decrease in free T levels.