Morning sickness

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Morning sickness
Other namesNausea and vomiting of pregnancy, nausea gravidarum, emesis gravidarum, pregnancy sickness
SpecialtyObstetrics
SymptomsNausea, vomiting[1]
ComplicationsWernicke encephalopathy, esophageal rupture[1]
Usual onset4th week of pregnancy[2]
DurationUntil 16th week of pregnancy[2]
CausesUnknown[2]
Diagnostic methodBased on symptoms after other causes have been ruled out[3]
Differential diagnosisHyperemesis gravidarum[1]
PreventionPrenatal vitamins[3]
TreatmentDoxylamine and pyridoxine[3][4]
Frequency~75% of pregnancies[4][5]

Morning sickness, also called nausea and vomiting of pregnancy (NVP), is a symptom of pregnancy that involves nausea or vomiting.[1] Despite the name, nausea or vomiting can occur at any time during the day.[2] Typically the symptoms occur between the 4th and 16th week of pregnancy.[2] About 10% of women still have symptoms after the 20th week of pregnancy.[2] A severe form of the condition is known as hyperemesis gravidarum and results in weight loss.[1][6]

The cause of morning sickness is unknown but may relate to changing levels of the hormone human chorionic gonadotropin.[2] Some have proposed that morning sickness may be useful from an evolutionary point of view.[1] Diagnosis should only occur after other possible causes have been ruled out.[3] Abdominal pain, fever, or headaches are typically not present in morning sickness.[1]

Taking prenatal vitamins before pregnancy may decrease the risk.[3] Specific treatment other than a bland diet may not be required for mild cases.[2][6][3] If treatment is used the combination of doxylamine and pyridoxine is recommended initially.[3][4] There is limited evidence that ginger may be useful.[3][7] For severe cases that have not improved with other measures methylprednisolone may be tried.[3] Tube feeding may be required in women who are losing weight.[3]

Morning sickness affects about 70–80% of all pregnant women to some extent.[4][5] About 60% of women experience vomiting.[2] Hyperemesis gravidarum occurs in about 1.6% of pregnancies.[1] Morning sickness can negatively affect quality of life, result in decreased ability to work while pregnant, and result in health-care expenses.[3] Generally, mild to moderate cases have no effect on the fetus, and most severe cases also have normal outcomes.[1] Some women choose to have an abortion due to the severity of symptoms.[1] Complications such as Wernicke encephalopathy or esophageal rupture may occur, but very rarely.[1]

Signs and symptoms[edit]

About 66% of women have both nausea and vomiting while 33% have just nausea.[1] Symptoms of both nausea and vomiting will normally climax around 10 and 16 weeks of pregnancy, subsiding around 20 weeks.[8] However, after around 22 weeks, up to 10% of women continue to have lingering symptoms.[8]

Cause[edit]

The cause of morning sickness is unknown but may relate to changing levels of estrogen and the hormone human chorionic gonadotropin.[2][9] Some have proposed that morning sickness may be useful from an evolutionary point of view, arguing that morning sickness may protect both the pregnant woman and the developing embryo just when the fetus is most vulnerable.[1] Diagnosis should only occur after other possible causes have been ruled out.[3] Abdominal pain, fever, or headaches are typically not present in morning sickness.[1]

Nausea and vomiting may also occur with molar pregnancy.[10]

Morning sickness is related to diets low in cereals and high in sugars, oilcrops, alcohol and meat.[11]

Pathophysiology[edit]

Hormone changes[edit]

Pathophysiology of vomiting in pregnancy

Defense mechanism[edit]

Morning sickness may be an evolved trait that protects the fetus against toxins ingested by the mother. Independent Scholar-Biologist Margie Profet from Seattle was one of the first to investigate the morning sickness-mystery. She argued that nausea and food aversions during pregnancy evolved to impose dietary restrictions on the mother in the early weeks of pregnancy, when the mother and the embryo are most immunologically vulnerable, to minimize fetal exposure to toxins such as mutagens and teratogens.[15] A woman and her embryo are very vulnerable to toxins during pregnancy. By reducing exposure to such chemicals, morning sickness reduces impairments on normal embryonic development and increases the reproductive success of the mother and survival success of both

the mother and her offspring. Evidence in support of this theory includes:[16][11]

  • Morning sickness is very common among pregnant women, which argues in favor of its being a functional adaptation and against the idea that it is a pathology.
  • Fetal vulnerability to toxins peaks at around 3 months, which is also the time of peak susceptibility to morning sickness.
  • There is a good correlation between toxin concentrations in foods, and the tastes and odors that cause revulsion.

Women who have no morning sickness are more likely to miscarry.[17] This may be because such women are more likely to ingest substances that are harmful to the fetus.[18]

In addition to protecting the fetus, morning sickness may also protect the mother. A pregnant woman's immune system is suppressed during pregnancy, presumably to reduce the chances of rejecting tissues of her own offspring.[19] Because of this, animal products containing parasites and harmful bacteria can be especially dangerous to pregnant women. There is evidence that morning sickness is often triggered by animal products including meat and fish.[20]

If morning sickness is a defense mechanism against the ingestion of toxins, the prescribing of anti-nausea medication to pregnant women may have the undesired side effect of causing birth defects or miscarriages by encouraging harmful dietary choices.[16]

Also morning sickness is a defense mechanism because when analyzing embryonic growth, several critical periods are identified in which there is mass proliferation and cell division resulting in the development of the heart and central nervous system that are very sensitive. In that period, the fetus is most at risk from damage to toxins and mutagens. These developments occur through week 6-18 which is in the same time frame in which the most nausea and vomiting of pregnancy (NVP) occurs. This relationship between the time at which the embryo is most susceptible to toxins lines up exactly with when the most severe NVP symptoms are seen, suggesting that this NVP is an evolutionary response developed in the mother, to indicate the sensitivity of the fetus hence making her wary to her health and in turn protecting the fetus.[20]

Treatments[edit]

There is a lack of good evidence to support the use of any particular intervention for morning sickness.[21]

Medications[edit]

A number of antiemetics are effective and safe in pregnancy including: pyridoxine/doxylamine, antihistamines (such as diphenhydramine), metoclopramide, and phenothiazines (such as promethazine).[22][23] With respect to effectiveness it is unknown if one is superior to another.[22] In the United States and Canada, the doxylamine-pyridoxine combination (as Diclegis in US and Diclectin in Canada) is the only approved pregnancy category "A" prescription treatment for nausea and vomiting of pregnancy.[23]

Ondansetron may be beneficial, but there are some concerns regarding an association with cleft palate,[24] and there is little high quality data.[22] Metoclopramide is also used and relatively well tolerated.[25] Evidence for the use of corticosteroids is weak.[26]

Alternative medicine[edit]

Some studies support the use of ginger, but overall the evidence is limited and inconsistent.[3][7][21][27][9] Safety concerns have been raised regarding its anticoagulant properties.[28][29][9][30]

History[edit]

Thalidomide[edit]

Thalidomide was originally developed and prescribed as a cure for morning sickness in West Germany, but its use was discontinued when it was found to cause birth defects.[31] The United States Food and Drug Administration never approved thalidomide for use as a cure for morning sickness.[32]

References[edit]

  1. ^ a b c d e f g h i j k l m n "Practice Bulletin No. 153: Nausea and Vomiting of Pregnancy". Obstetrics and Gynecology. 126 (3): e12–e24. September 2015. doi:10.1097/AOG.0000000000001048. PMID 26287788. S2CID 19552518.
  2. ^ a b c d e f g h i j Festin M (June 2009). "Nausea and vomiting in early pregnancy". BMJ Clinical Evidence. 2009. PMC 2907767. PMID 21726485.
  3. ^ a b c d e f g h i j k l m "Practice Bulletin Summary No. 153: Nausea and Vomiting of Pregnancy". Obstetrics and Gynecology. 126 (3): 687–688. September 2015. doi:10.1097/01.aog.0000471177.80067.19. PMID 26287781. S2CID 39256123.
  4. ^ a b c d Koren G (December 2014). "Treating morning sickness in the United States--changes in prescribing are needed". American Journal of Obstetrics and Gynecology. 211 (6): 602–606. doi:10.1016/j.ajog.2014.08.017. PMID 25151184.
  5. ^ a b Einarson TR, Piwko C, Koren G (2013-01-01). "Prevalence of nausea and vomiting of pregnancy in the USA: a meta analysis". Journal of Population Therapeutics and Clinical Pharmacology. 20 (2): e163–e170. PMID 23863545.
  6. ^ a b "Pregnancy". Office on Women's Health. September 27, 2010. Archived from the original on 10 December 2015. Retrieved 5 December 2015.
  7. ^ a b Matthews A, Haas DM, O'Mathúna DP, Dowswell T (September 2015). "Interventions for nausea and vomiting in early pregnancy". The Cochrane Database of Systematic Reviews. 2015 (9): CD007575. doi:10.1002/14651858.CD007575.pub4. PMC 4004939. PMID 26348534.open access
  8. ^ a b Lee NM, Saha S (June 2011). "Nausea and vomiting of pregnancy". Gastroenterology Clinics of North America. 40 (2): 309–34, vii. doi:10.1016/j.gtc.2011.03.009. PMC 3676933. PMID 21601782.
  9. ^ a b c Viljoen E, Visser J, Koen N, Musekiwa A (March 2014). "A systematic review and meta-analysis of the effect and safety of ginger in the treatment of pregnancy-associated nausea and vomiting". Nutrition Journal. 13: 20. doi:10.1186/1475-2891-13-20. PMC 3995184. PMID 24642205.
  10. ^ Verberg MF, Gillott DJ, Al-Fardan N, Grudzinskas JG (2005). "Hyperemesis gravidarum, a literature review". Human Reproduction Update. 11 (5): 527–539. doi:10.1093/humupd/dmi021. PMID 16006438.
  11. ^ a b Pepper GV, Craig Roberts S (October 2006). "Rates of nausea and vomiting in pregnancy and dietary characteristics across populations". Proceedings. Biological Sciences. 273 (1601): 2675–2679. doi:10.1098/rspb.2006.3633. PMC 1635459. PMID 17002954.
  12. ^ Lagiou P, Tamimi R, Mucci LA, Trichopoulos D, Adami HO, Hsieh CC (April 2003). "Nausea and vomiting in pregnancy in relation to prolactin, estrogens, and progesterone: a prospective study". Obstetrics and Gynecology. 101 (4): 639–644. doi:10.1016/s0029-7844(02)02730-8. PMID 12681864. S2CID 13103469.
  13. ^ Bauchner E, Marquez W. "Morning Sickness: Coping With The Worst". NY Metro Parents Magazine. Archived from the original on 2008-12-04. Retrieved 2008-07-06.
  14. ^ Niebyl JR (October 2010). "Clinical practice. Nausea and vomiting in pregnancy". The New England Journal of Medicine. 363 (16): 1544–1550. doi:10.1056/NEJMcp1003896. PMID 20942670.
  15. ^ Holt RD, Nesse RM, Williams GC (April 1996). "Why We Get Sick: The New Science of Darwinian Medicine". Ecology. 77 (3): 983. doi:10.2307/2265522. ISSN 0012-9658. JSTOR 2265522.
  16. ^ a b Nesse RM, Williams GC (1996). Why We Get Sick (1st ed.). New York: Vintage Books. p. 290.
  17. ^ Chan RL, Olshan AF, Savitz DA, Herring AH, Daniels JL, Peterson HB, Martin SL (November 2010). "Severity and duration of nausea and vomiting symptoms in pregnancy and spontaneous abortion". Human Reproduction. 25 (11): 2907–2912. doi:10.1093/humrep/deq260. PMC 3140259. PMID 20861299.
  18. ^ Sherman PW, Flaxman SM (May 2002). "Nausea and vomiting of pregnancy in an evolutionary perspective". American Journal of Obstetrics and Gynecology. 186 (5 Suppl Understanding): S190–S197. CiteSeerX 10.1.1.611.7889. doi:10.1067/mob.2002.122593. PMID 12011885.
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  20. ^ a b Flaxman SM, Sherman PW (June 2000). "Morning sickness: a mechanism for protecting mother and embryo". The Quarterly Review of Biology. 75 (2): 113–148. doi:10.1086/393377. PMID 10858967. S2CID 28668687.
  21. ^ a b Matthews A, Haas DM, O'Mathúna DP, Dowswell T (September 2015). "Interventions for nausea and vomiting in early pregnancy". The Cochrane Database of Systematic Reviews. 2015 (9): CD007575. doi:10.1002/14651858.CD007575.pub4. PMC 4004939. PMID 26348534.
  22. ^ a b c Jarvis S, Nelson-Piercy C (June 2011). "Management of nausea and vomiting in pregnancy". BMJ. 342: d3606. doi:10.1136/bmj.d3606. PMID 21685438. S2CID 32242306.
  23. ^ a b Clark SM, Dutta E, Hankins GD (December 2014). "The outpatient management and special considerations of nausea and vomiting in pregnancy". Seminars in Perinatology. 38 (8): 496–502. doi:10.1053/j.semperi.2014.08.014. PMID 25267280.
  24. ^ Koren G (October 2012). "Motherisk update. Is ondansetron safe for use during pregnancy?". Canadian Family Physician. 58 (10): 1092–1093. PMC 3470505. PMID 23064917.
  25. ^ Tan PC, Omar SZ (April 2011). "Contemporary approaches to hyperemesis during pregnancy". Current Opinion in Obstetrics & Gynecology. 23 (2): 87–93. doi:10.1097/GCO.0b013e328342d208. PMID 21297474. S2CID 11743580.
  26. ^ Poon SL (October 2011). "Towards evidence-based emergency medicine: Best BETs from the Manchester Royal Infirmary. BET 2: Steroid therapy in the treatment of intractable hyperemesis gravidarum". Emergency Medicine Journal. 28 (10): 898–900. doi:10.1136/emermed-2011-200636. PMID 21918097. S2CID 6667779.
  27. ^ Thomson M, Corbin R, Leung L (2014). "Effects of ginger for nausea and vomiting in early pregnancy: a meta-analysis". Journal of the American Board of Family Medicine. 27 (1): 115–122. doi:10.3122/jabfm.2014.01.130167. PMID 24390893.
  28. ^ Borrelli F, Capasso R, Aviello G, Pittler MH, Izzo AA (April 2005). "Effectiveness and safety of ginger in the treatment of pregnancy-induced nausea and vomiting". Obstetrics and Gynecology. 105 (4): 849–856. doi:10.1097/01.AOG.0000154890.47642.23. PMID 15802416. S2CID 1607109.
  29. ^ Tiran D (February 2012). "Ginger to reduce nausea and vomiting during pregnancy: evidence of effectiveness is not the same as proof of safety". Complementary Therapies in Clinical Practice. 18 (1): 22–25. doi:10.1016/j.ctcp.2011.08.007. PMID 22196569.
  30. ^ Hu Y, Amoah AN, Zhang H, Fu R, Qiu Y, Cao Y, et al. (January 2022). "Effect of ginger in the treatment of nausea and vomiting compared with vitamin B6 and placebo during pregnancy: a meta-analysis". The Journal of Maternal-Fetal & Neonatal Medicine. 35 (1): 187–196. doi:10.1080/14767058.2020.1712714. PMID 31937153. S2CID 210827751.
  31. ^ Cohen WR, ed. (2000). Cherry and Merkatz's complications of pregnancy (5th ed.). Lippincott Williams & Wilkins. p. 124. ISBN 9780683016734.
  32. ^ Bren L (2001-02-28). "Frances Oldham Kelsey: FDA Medical Reviewer Leaves Her Mark on History". FDA Consumer. U.S. Food and Drug Administration. Retrieved 2009-12-23.