Morning sickness

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Morning sickness, also called "nausea and vomiting of pregnancy" (NVP) or pregnancy sickness, affects between 50 and 95 percent of all pregnant women. It is also sometimes experienced by women who take birth control pills or hormone replacement therapy. The amount of nausea can vary from mild amounts to actual vomiting. In extreme cases, known as hyperemesis gravidarum, hospital admission may be required to correct the resulting dehydration.

1 When it occurs
2 Causes
3 Treatments
- 3.1 Thalidomide tragedy
- 3.2 Research
4 Associations with miscarriage risk
5 External links
6 Notes

[edit] When it occurs

Morning sickness is not confined to the morning: nausea can occur at any time of the day, though it most commonly occurs soon after waking because blood sugar levels are typically the most depressed after these hours without eating.^{[citation needed]}

Morning sickness usually starts in the first month of the pregnancy, peaking in the 5th to 7th weeks, and continuing until the 14th to 16th week. For 50% of all sufferers, it ends by the 16th week of pregnancy. For the other half, it may take up to another month to get relief but some women will have morning sickness off and on for their entire pregnancy.

[edit] Causes

There is insufficient evidence to pin down a single (or multiple) cause, but the leading theories include:

An increase in the circulating level of the hormone estrogen. Estrogen levels may increase by up to a hundredfold during pregnancy.
Low blood sugar during pregnancy.
An increase in progesterone relaxes the muscles in the uterus, which prevents early childbirth, but may also relax the stomach and intestines, leading to excess stomach acids.
An increase in human chorionic gonadotropin.
An increase in sensitivity to odors.
Eating vegetables. Vegetables produce a small amount of toxins to deter insect infestation and while these toxins are normally harmless to humans, they are potentially dangerous to embryos. One theory suggests that becoming nauseated during pregnancy is an evolutionary measure to prevent a mother from eating vegetables, thereby protecting the embryo from the toxins. Other studies, however, have linked consumption of fruits and vegetables to higher birth weights, which tend to mean healthier babies.
Intake of alcohol, sugar, oils and meat, which have been postulated to cause a natural trigger of morning sickness in the body as a way of discouraging ingestion of less healthy foods.<ref>Gillian V. Pepper and S. Craig Roberts "Rates of nausea and vomiting in pregnancy and dietary characteristics across populations" from Proceedings of The Royal Society</ref>

[edit] Treatments

Treatments for morning sickness typically aim to lessen the symptoms of nausea, rather than attacking the root cause(s) of the nausea. Treatments include:

Avoiding an empty stomach
Eating five or six small meals per day, rather than three large ones
Ginger, in capsules, tea, ginger ale, ginger beer or ginger snaps<ref>Borrelli, Francesca et al. "Effectiveness and Safety of Ginger in the Treatment of Pregnancy-Induced Nausea and Vomiting," Obstetrics & Gynecology. September 1, 2005; 106(3): 640 - 641.</ref>
Vitamin B6 (either pyridoxine or pyridoxamine), often taken in combination with the antihistamine doxylamine (Diclectin^®).
Lemons, particularly the smelling of freshly cut lemons
Fulfilling food cravings
Eating dry crackers in the morning.

A doctor may prescribe anti-nausea medications if the expectant mother suffers from dehydration or malnutrition as a result of her morning sickness. In the US, Zofran (ondansetron) is the usual drug of choice, though the high cost is prohibitive for some women; in the UK, older drugs with which there is a greater experience of use in pregnancy are preferred, with first choice being promethazine otherwise as second choice metoclopramide, or prochlorperazine.<ref name="BNF">British National Formulary (March 2003). “4.6 Drugs used in nausea and vertigo - Vomiting of pregnancy”, "BNF", 45.</ref>

[edit] Thalidomide tragedy

Further information: Thalidomide#The thalidomide tragedy

Thalidomide was originally developed and prescribed as a cure for morning sickness in Great Britain, but its use was discontinued when the drug's teratogenic properties came to light. The United States Food and Drug Administration never approved thalidomide for use as a cure for morning sickness.

[edit] Research

A recent Canadian survey conducted by researchers at the University of British Columbia and the University of Victoria suggested that the use of medical marijuana may be effective in combating morning sickness,<ref name="ComplementTherClinPract2006-Westfall">Westfall R, Janssen P, Lucas P, Capler R (2006). "Survey of medicinal cannabis use among childbearing women: patterns of its use in pregnancy and retroactive self-assessment of its efficacy against 'morning sickness'.". Complement Ther Clin Pract 12 (1): 27-33. PMID 16401527.</ref> although the researchers noted that their survey was not conclusive.<ref name="NationalPost-Blackwell">Tom Blackwell. "More pregnancy highs than lows", National Post, 2006-01-17. Retrieved on 2006-06-07.</ref>

[edit] Associations with miscarriage risk

Studies have shown that women who suffer from morning sickness are less likely to have miscarriages, while other studies have shown that the majority of women who do miscarry had multiple pregnancy symptoms including pregnancy sickness. Some doctors refute the claim that lack of morning sickness indicates an increased risk of miscarriage. They claim the mother's sensitivity to the changes in her body is not a variable that indicates risk of miscarriage. It is also mentioned that many women having a molar pregnancy or an ectopic pregnancy suffer strong nausea.