Morning sickness

About 66% of women have both nausea and vomiting while 33% have just nausea. Symptoms of both nausea and vomiting will normally climax around 10 and 16 weeks of pregnancy, subsiding around 20 weeks. However, after around 22 weeks, up to 10% of women continue to have lingering symptoms.{{cite journal | vauthors = Lee NM, Saha S | title = Nausea and vomiting of pregnancy | journal = Gastroenterology Clinics of North America | volume = 40 | issue = 2 | pages = 309–34, vii | date = June 2011 | pmid = 21601782 | pmc = 3676933 | doi = 10.1016/j.gtc.2011.03.009 }}

The cause of morning sickness is unknown but may relate to changing levels of estrogen and the hormone human chorionic gonadotropin.{{cite journal |vauthors=Viljoen E, Visser J, Koen N, Musekiwa A |date=March 2014 |title=A systematic review and meta-analysis of the effect and safety of ginger in the treatment of pregnancy-associated nausea and vomiting |journal=Nutrition Journal |type=Systematic review; meta-analysis |volume=13 |pages=20 |doi=10.1186/1475-2891-13-20 |pmc=3995184 |pmid=24642205 |doi-access=free}} Some have proposed that morning sickness may be useful from an evolutionary point of view -it may protect both the pregnant woman and the developing embryo just when the fetus is most vulnerable. Diagnosis should only occur after other possible causes have been ruled out. Abdominal pain, fever, or headaches are typically not present in morning sickness.

Nausea and vomiting may also occur with molar pregnancy.{{cite journal | vauthors = Verberg MF, Gillott DJ, Al-Fardan N, Grudzinskas JG | title = Hyperemesis gravidarum, a literature review | journal = Human Reproduction Update | volume = 11 | issue = 5 | pages = 527–539 | date = 2005 | pmid = 16006438 | doi = 10.1093/humupd/dmi021 | doi-access = free }}

Morning sickness is related to diets low in cereals and high in sugars, oilcrops, alcohol and meat.{{cite journal | vauthors = Pepper GV, Craig Roberts S | title = Rates of nausea and vomiting in pregnancy and dietary characteristics across populations | journal = Proceedings. Biological Sciences | volume = 273 | issue = 1601 | pages = 2675–2679 | date = October 2006 | pmid = 17002954 | pmc = 1635459 | doi = 10.1098/rspb.2006.3633 }}

File:Morning sickness.svg

• An increase in the circulating level of the hormone estrogen.{{cite journal | vauthors = Lagiou P, Tamimi R, Mucci LA, Trichopoulos D, Adami HO, Hsieh CC | title = Nausea and vomiting in pregnancy in relation to prolactin, estrogens, and progesterone: a prospective study | journal = Obstetrics and Gynecology | volume = 101 | issue = 4 | pages = 639–644 | date = April 2003 | pmid = 12681864 | doi = 10.1016/s0029-7844(02)02730-8 | s2cid = 13103469 }} However, there is no consistent evidence of differences in estrogen levels and levels of bilirubin between women that experience sickness and those that do not.{{cite web|url=http://www.nymetroparents.com/newarticle.cfm?colid=7114|title=Morning Sickness: Coping With The Worst|publisher=NY Metro Parents Magazine|access-date=2008-07-06| vauthors = Bauchner E, Marquez W |url-status=dead|archive-url=https://web.archive.org/web/20081204115500/http://www.nymetroparents.com/newarticle.cfm?colid=7114|archive-date=2008-12-04}} Related to increased estrogen levels, a similar form of nausea is also seen in some women who use hormonal contraception or hormone replacement therapy, but does not predict future reactions to 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 and gastroesophageal reflux disease (GERD).
• An increase in human chorionic gonadotropin. It is probably not the HCG itself that causes the nausea. More likely, it is the HCG stimulating the maternal ovaries to secrete estrogen, which in turn causes the nausea.{{cite journal | vauthors = Niebyl JR | title = Clinical practice. Nausea and vomiting in pregnancy | journal = The New England Journal of Medicine | volume = 363 | issue = 16 | pages = 1544–1550 | date = October 2010 | pmid = 20942670 | doi = 10.1056/NEJMcp1003896 }}

Morning sickness may be an evolved trait that protects the fetus against toxins ingested by the mother. Biologist Margie Profet believes 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.{{Cite book |title=Why We Get Sick: The New Science of Darwinian Medicine. |vauthors=Holt RD, Nesse RM, Williams GC |date=April 1996 |isbn=978-0679746744 |pages=983|publisher=Knopf Doubleday Publishing }} 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:{{cite book | vauthors = Nesse RM, Williams GC |author-link2=George C. Williams (biologist) |title= Why We Get Sick |year=1996 |edition=1st |publisher= Vintage Books|location= New York |pages=290 }}

• 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.{{cite journal | vauthors = Chan RL, Olshan AF, Savitz DA, Herring AH, Daniels JL, Peterson HB, Martin SL | title = Severity and duration of nausea and vomiting symptoms in pregnancy and spontaneous abortion | journal = Human Reproduction | volume = 25 | issue = 11 | pages = 2907–2912 | date = November 2010 | pmid = 20861299 | pmc = 3140259 | doi = 10.1093/humrep/deq260 | author4-link = Amy H. Herring }}{{Cite web |last=Collins |first=Dr Francis |date=2016-10-04 |title=Morning Sickness Associated with Lower Miscarriage Risk |url=https://directorsblog.nih.gov/2016/10/04/nausea-in-pregnancy-is-associated-with-lower-miscarriage-risk/ |access-date=2023-06-25 |website=NIH Director's Blog |language=en-US}} This may be because such women are more likely to ingest substances that are harmful to the fetus.{{cite journal | vauthors = Sherman PW, Flaxman SM | title = Nausea and vomiting of pregnancy in an evolutionary perspective | journal = American Journal of Obstetrics and Gynecology | volume = 186 | issue = 5 Suppl Understanding | pages = S190–S197 | date = May 2002 | pmid = 12011885 | doi = 10.1067/mob.2002.122593 | citeseerx = 10.1.1.611.7889 }}

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.{{cite journal | vauthors = Haig D | title = Genetic conflicts in human pregnancy | journal = The Quarterly Review of Biology | volume = 68 | issue = 4 | pages = 495–532 | date = December 1993 | pmid = 8115596 | doi = 10.1086/418300 | s2cid = 38641716 | url = http://nrs.harvard.edu/urn-3:HUL.InstRepos:3153297 | author-link = David Haig (biologist) }} 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.{{cite journal | vauthors = Flaxman SM, Sherman PW | title = Morning sickness: a mechanism for protecting mother and embryo | journal = The Quarterly Review of Biology | volume = 75 | issue = 2 | pages = 113–148 | date = June 2000 | pmid = 10858967 | doi = 10.1086/393377 | s2cid = 28668687 }}

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.

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.

Emerging research suggests that the health of the male partner and the quality of his sperm may influence the severity of morning sickness experienced by a pregnant woman. Studies have shown that sperm DNA integrity, epigenetic factors, and overall sperm health can affect early placental development and hormone regulation, which are linked to the onset and severity of nausea and vomiting during pregnancy (NVP). For example:

1. Sperm DNA Fragmentation: High levels of sperm DNA damage have been associated with abnormal placental development, which may disrupt hormone levels such as human chorionic gonadotropin (hCG) and contribute to more severe morning sickness. {{Cite journal |last1=Agarwal |first1=Ashok |last2=Majzoub |first2=Ahmad |last3=Esteves |first3=Sandro C. |last4=Ko |first4=Edmund |last5=Ramasamy |first5=Ranjith |last6=Zini |first6=Armand |date=December 2016 |title=Clinical utility of sperm DNA fragmentation testing: practice recommendations based on clinical scenarios |journal=Translational Andrology and Urology |language=en |volume=5 |issue=6 |pages=93550–93950 |doi=10.21037/tau.2016.10.03 |doi-access=free |issn=2223-4691 |pmc=5182232 |pmid=28078226}}
2. Epigenetic Modifications: Sperm carry epigenetic markers that can influence gene expression in the developing embryo and placenta. These modifications may affect the production of hormones like hCG and estrogen, which are directly linked to NVP. {{Cite journal |last1=Soubry |first1=Adelheid |last2=Hoyo |first2=Cathrine |last3=Jirtle |first3=Randy L. |last4=Murphy |first4=Susan K. |date=2014 |title=A paternal environmental legacy: Evidence for epigenetic inheritance through the male germ line |journal=BioEssays |language=en |volume=36 |issue=4 |pages=359–371 |doi=10.1002/bies.201300113 |issn=1521-1878 |pmc=4047566 |pmid=24431278}}
3. Lifestyle Factors: Male lifestyle factors such as smoking, alcohol consumption, and obesity can negatively impact sperm quality. Poor sperm health has been correlated with complications in early pregnancy, including heightened NVP symptoms. {{Cite journal |last1=Sharma |first1=Reecha |last2=Harlev |first2=Avi |last3=Agarwal |first3=Ashok |last4=Esteves |first4=Sandro C. |date=2016-10-01 |title=Cigarette Smoking and Semen Quality: A New Meta-analysis Examining the Effect of the 2010 World Health Organization Laboratory Methods for the Examination of Human Semen |url=https://linkinghub.elsevier.com/retrieve/pii/S0302283816300690 |journal=European Urology |volume=70 |issue=4 |pages=635–645 |doi=10.1016/j.eururo.2016.04.010 |pmid=27113031 |issn=0302-2838}}

While the exact mechanisms remain under investigation, these findings highlight the importance of male preconception health as a potential factor in the severity of morning sickness.

There is a lack of good evidence to support the use of any particular intervention for morning sickness.{{cite journal |vauthors=Matthews A, Haas DM, O'Mathúna DP, Dowswell T |date=September 2015 |title=Interventions for nausea and vomiting in early pregnancy |journal=The Cochrane Database of Systematic Reviews |type=Systematic review; meta-analysis |volume=2015 |issue=9 |pages=CD007575 |doi=10.1002/14651858.CD007575.pub4 |pmc=4004939 |pmid=26348534 |doi-access=free}}

A number of antiemetics are effective and safe in pregnancy including: pyridoxine/doxylamine, antihistamines (such as diphenhydramine), metoclopramide, and phenothiazines (such as promethazine).{{cite journal |vauthors=Jarvis S, Nelson-Piercy C |date=June 2011 |title=Management of nausea and vomiting in pregnancy |url=https://www.bmj.com/content/342/bmj.d3606 |journal=The BMJ |type=Review |volume=342 |pages=d3606 |doi=10.1136/bmj.d3606 |pmid=21685438 |s2cid=32242306 |url-access=subscription}} With respect to effectiveness it is unknown if one is superior to another. 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.{{cite journal |vauthors=Clark SM, Dutta E, Hankins GD |date=December 2014 |title=The outpatient management and special considerations of nausea and vomiting in pregnancy |url=https://www.sciencedirect.com/science/article/abs/pii/S0146000514001025 |journal=Seminars in Perinatology |type=Review |volume=38 |issue=8 |pages=496–502 |doi=10.1053/j.semperi.2014.08.014 |pmid=25267280 |url-access=subscription}}

Ondansetron may be beneficial, but there are some concerns regarding an association with cleft palate,{{cite journal |vauthors=Koren G |date=October 2012 |title=Is ondansetron safe for use during pregnancy? |url=https://www.cfp.ca/content/58/10/1092 |department=Motherisk update |journal=Canadian Family Physician |volume=58 |issue=10 |pages=1092–1093 |doi= |pmc=3470505 |pmid=23064917 |url-access=}} and there is little high quality data. Metoclopramide is also used and relatively well tolerated.{{cite journal |vauthors=Tan PC, Omar SZ |date=April 2011 |title=Contemporary approaches to hyperemesis during pregnancy |url=https://journals.lww.com/co-obgyn/abstract/2011/04000/contemporary_approaches_to_hyperemesis_during.6.aspx |department=Maternal-Fetal Medicine |journal=Current Opinion in Obstetrics & Gynecology |type=Review |volume=23 |issue=2 |pages=87–93 |doi=10.1097/GCO.0b013e328342d208 |pmid=21297474 |s2cid=11743580 |url-access=subscription}} Evidence for the use of corticosteroids is weak.{{cite journal |vauthors=Poon SL |date=October 2011 |title=BET 2: Steroid therapy in the treatment of intractable hyperemesis gravidarum |url=https://emj.bmj.com/content/28/10/898.3 |department=Best Evidence Topic reports |journal=Emergency Medicine Journal |type=Review |volume=28 |issue=10 |pages=898–900 |doi=10.1136/emermed-2011-200636 |pmid=21918097 |s2cid=6667779 |url-access=subscription}}

A recent review of studies has found acupuncture to be safe and effective for NVP.{{Cite journal |last1=Hu |first1=Yao |last2=Yang |first2=Qian |last3=Hu |first3=Xianjin |date=2024 |title=The efficacy and safety of acupuncture and moxibustion for the management of nausea and vomiting in pregnant women: A systematic review and meta-analysis |journal=Heliyon |volume=10 |issue=2 |pages=e24439 |doi=10.1016/j.heliyon.2024.e24439 |doi-access=free |pmid=38298660 |issn=2405-8440|pmc=10828706 |bibcode=2024Heliy..1024439H }} Acupressure applied at the acupuncture point PC6 with finger pressure or a nausea band has some evidence of effectiveness,{{Cite journal |date=2018 |title=ACOG Practice Bulletin No. 189: Nausea And Vomiting Of Pregnancy |url=https://journals.lww.com/00006250-201801000-00039 |journal=Obstetrics & Gynecology |language=en |volume=131 |issue=1 |pages=e15–e30 |doi=10.1097/AOG.0000000000002456 |pmid=29266076 |issn=0029-7844 |author1=Committee on Practice Bulletins-Obstetrics }}{{Cite book |title=Management of nausea and vomiting in pregnancy: Antenatal care: Evidence review (NICE Guideline No. 201) |publisher=National Guideline Alliance (UK) |year=2021 |isbn=978-1-4731-4227-5 |location=London, UK}} as does auricular (ear acupuncture).

Some studies support the use of ginger, but overall the evidence is limited and inconsistent.{{cite journal |vauthors=Thomson M, Corbin R, Leung L |year=2014 |title=Effects of ginger for nausea and vomiting in early pregnancy: a meta-analysis |url=https://www.jabfm.org/content/27/1/115 |journal=Journal of the American Board of Family Medicine |type=Meta-analysis |volume=27 |issue=1 |pages=115–122 |doi=10.3122/jabfm.2014.01.130167 |pmid=24390893 |doi-access=free}} Safety concerns have been raised regarding its anticoagulant properties.{{cite journal |vauthors=Borrelli F, Capasso R, Aviello G, Pittler MH, Izzo AA |date=April 2005 |title=Effectiveness and safety of ginger in the treatment of pregnancy-induced nausea and vomiting |url=https://journals.lww.com/greenjournal/abstract/2005/04000/effectiveness_and_safety_of_ginger_in_the.27.aspx |journal=Obstetrics and Gynecology |volume=105 |issue=4 |pages=849–856 |doi=10.1097/01.AOG.0000154890.47642.23 |pmid=15802416 |s2cid=1607109 |url-access=subscription}}{{cite journal |vauthors=Tiran D |date=February 2012 |title=Ginger to reduce nausea and vomiting during pregnancy: evidence of effectiveness is not the same as proof of safety |url=https://www.sciencedirect.com/science/article/abs/pii/S1744388111000739 |journal=Complementary Therapies in Clinical Practice |type=Review |volume=18 |issue=1 |pages=22–25 |doi=10.1016/j.ctcp.2011.08.007 |pmid=22196569 |url-access=subscription}}{{cite journal |display-authors=6 |vauthors=Hu Y, Amoah AN, Zhang H, Fu R, Qiu Y, Cao Y, Sun Y, Chen H, Liu Y, Lyu Q |date=January 2022 |title=Effect of ginger in the treatment of nausea and vomiting compared with vitamin B6 and placebo during pregnancy: a meta-analysis |url=https://www.tandfonline.com/doi/full/10.1080/14767058.2020.1712714 |journal=The Journal of Maternal-Fetal & Neonatal Medicine |type=Meta-analysis |volume=35 |issue=1 |pages=187–196 |doi=10.1080/14767058.2020.1712714 |pmid=31937153 |s2cid=210827751 |url-access=subscription}}

{{Main|Thalidomide scandal}}

In the late 1950s and early 1960s, the use of thalidomide in 46 countries by women who were pregnant or who subsequently became pregnant resulted in the "biggest man‐made medical disaster ever," with more than 10,000 children born with a range of severe deformities, such as phocomelia, as well as thousands of miscarriages.Vargesson, Neil. “Thalidomide-induced teratogenesis: history and mechanisms.” Birth defects research. Part C, Embryo today : reviews vol. 105,2 (2015): 140–56. doi:10.1002/bdrc.21096{{cite news | author = Bren L | title =Frances Oldham Kelsey: FDA Medical Reviewer Leaves Her Mark on History | url =http://permanent.access.gpo.gov/lps1609/www.fda.gov/fdac/features/2001/201_kelsey.html | work =FDA Consumer|publisher =U.S. Food and Drug Administration | date =28 February 2001 | access-date =23 December 2009}}

Thalidomide was introduced in 1953 as a tranquilizer, and was later marketed by the German pharmaceutical company Chemie Grünenthal under the trade name Contergan as a medication for anxiety, trouble sleeping, "tension", and morning sickness.{{cite journal | last = Miller | first = Marylin T. | name-list-style = vanc | title = Thalidomide Embryopathy: A Model for the Study of Congenital Incomitant Horizontal Strabismus | journal = Transactions of the American Ophthalmological Society | year = 1991 | volume = 81 | pages = 623–674 | pmid = 1808819 | pmc = 1298636 }}{{cite book |last1=Loue |first1=Sana |last2=Sajatovic |first2=Martha | name-list-style = vanc |title=Encyclopedia of Women's Health |date=2004 |publisher=Springer Science & Business Media |isbn=9780306480737 |pages=643–644 |url=https://books.google.com/books?id=LbHWgd-mDbsC&pg=PA644 |language=en}} It was introduced as a sedative and medication for morning sickness without having been tested on pregnant women.{{cite book|last1=Sneader|first1=Walter | name-list-style = vanc |title=Drug discovery: a history|url=https://archive.org/details/drugdiscoveryhis00snea|url-access=limited|date=2005|publisher=Wiley|location=Chichester|isbn=978-0-471-89979-2|page=[https://archive.org/details/drugdiscoveryhis00snea/page/n380 367]|edition=Rev. and updated}} While initially deemed to be safe in pregnancy, concerns regarding birth defects were noted in 1961, and the medication was removed from the market in Europe that year.{{cite book | title = The Oxford Companion to the Body | last = Cuthbert | first = Alan | name-list-style = vanc | year = 2003 | publisher = Oxford University Press | url = https://archive.org/details/oxfordcompaniont0000unse_z0k4/page/682 | doi = 10.1093/acref/9780198524038.001.0001 | isbn = 9780198524038 | url-access = registration | page = [https://archive.org/details/oxfordcompaniont0000unse_z0k4/page/682 682] }}

{{Reflist}}

{{Medical resources

| ICD10 = {{ICD10|O|21.0}}

| ICD9 = {{ICD9|643.0}}

| MedlinePlus = 003119

|ICD11={{ICD11|SC00}}}}

{{Pathology of pregnancy, childbirth and the puerperium}}

{{Authority control}}

{{DEFAULTSORT:Morning Sickness}}

Category:Health issues in pregnancy

Category:Vomiting

Category:Gynaecology

Category:Obstetrics

Category:Midwifery

Category:Wikipedia medicine articles ready to translate