Editing Obstetrics (section)

== Main areas ==

=== Prenatal care ===
Prenatal care is important in screening for various [[complications of pregnancy]].<ref>{{cite book | vauthors = Tulchinsky TH, Varavikova EA | chapter = Chapter 6 - Family Health | title = The new public health. | publisher = Academic Press | date = March 2014 | pages = 311–379 | edition = Third | doi = 10.1016/B978-0-12-415766-8.00006-9 | isbn = 978-0-12-415766-8 }}</ref> This includes routine office visits with physical exams and routine lab tests along with telehealth care for women with low-risk pregnancies:<ref>{{Cite journal |last1=Cantor |first1=Amy G. |last2=Jungbauer |first2=Rebecca M. |last3=Totten |first3=Annette M. |last4=Tilden |first4=Ellen L. |last5=Holmes |first5=Rebecca |last6=Ahmed |first6=Azrah |last7=Wagner |first7=Jesse |last8=Hermesch |first8=Amy C. |last9=McDonagh |first9=Marian S. |date=2022 |title=Telehealth Strategies for the Delivery of Maternal Health Care: A Rapid Review |url=https://www.acpjournals.org/doi/10.7326/M22-0737 |journal=Annals of Internal Medicine |language=en |volume=175 |issue=9 |pages=1285–1297 |doi=10.7326/M22-0737 |pmid=35878405 |s2cid=251067668 |issn=0003-4819}}</ref>

<gallery class="center">
Image:Ultrasound_image_of_a_fetus.jpg|[[3D ultrasound]] of {{convert|3|in|mm|adj=on}} fetus (about 14 weeks [[Gestational age (obstetrics)|gestational age]])
Image:Sucking his thumb and waving.jpg|Fetus at 17 weeks
Image:3dultrasound 20 weeks.jpg|Fetus at 20 weeks
</gallery>

==== First trimester ====
Routine tests in the first [[Trimester (pregnancy)|trimester]] of pregnancy generally include:
* [[Complete blood count]]
* [[Blood type]]
** [[Rh blood group system|Rh-negative]] antenatal patients should receive [[Rho(D) immune globulin|RhoGAM]] at 28 weeks to prevent [[Rh disease]].
* [[Coombs test#Indirect Coombs test|Indirect Coombs test]] (AGT) to assess risk of [[hemolytic disease of the newborn]]<ref>{{Cite web | vauthors = Rath L |title=What Is a Coombs Test? |url=https://www.webmd.com/a-to-z-guides/antibody-coombs-test |access-date=2022-04-29 |website=WebMD |language=en}}</ref>
* [[Rapid plasma reagin]] test to screen for [[syphilis]]
* [[Rubella]] antibody screen<ref>{{Cite web | vauthors = Rath L |title=Why Do I Need a Rubella Test? |url=https://www.webmd.com/a-to-z-guides/rubella-test-antibodies |access-date=2022-04-29 |website=WebMD |language=en}}</ref>
* [[HBsAg]] test to screen for [[hepatitis B]]<ref>{{Cite journal|date=2021-04-03 | vauthors = Mekaroonkamol P, Hashemi N | veditors = Staros EB |title=Hepatitis B Test: Reference Range, Interpretation, Collection and Panels |url=https://emedicine.medscape.com/article/2109144-overview | journal = Medscape }}</ref>
* Testing for [[chlamydia]] (and [[gonorrhea]] when indicated<ref name="pmid24548498">{{cite journal | vauthors = Fontenot HB, George ER | title = Sexually transmitted infections in pregnancy | journal = Nursing for Women's Health | volume = 18 | issue = 1 | pages = 67–72 | date = 2014 | pmid = 24548498 | doi = 10.1111/1751-486X.12095 }}</ref>
* [[Mantoux test]] for [[tuberculosis]]<ref>{{Cite web |last=CDCTB |date=2020-12-16 |title=Tuberculosis (TB) Fact Sheets- Tuberculin Skin Testing |url=https://www.cdc.gov/tb/publications/factsheets/testing/skintesting.htm |access-date=2022-04-29 |website=Centers for Disease Control and Prevention |language=en-us}}</ref>
* [[Urinalysis]] and culture<ref>{{Cite web |title=Urinalysis: What It Is, Purpose, Types & Results |url=https://my.clevelandclinic.org/health/diagnostics/17893-urinalysis |access-date=2022-04-29 |website=Cleveland Clinic}}</ref>
* [[HIV]] screen

Genetic screening for [[Down syndrome]] (trisomy 21) and [[Edwards syndrome]] (trisomy 18), the national standard in the United States, is rapidly evolving away from the AFP-[[quad screen]], done typically in the second trimester at 16–18 weeks.<ref>{{cite journal | vauthors = Cereda A, Carey JC | title = The trisomy 18 syndrome | journal = Orphanet Journal of Rare Diseases | volume = 7 | pages = 81 | date = October 2012 | pmid = 23088440 | pmc = 3520824 | doi = 10.1186/1750-1172-7-81 | doi-access = free }}</ref> The newer integrated screen (formerly called F.A.S.T.E.R for First And Second Trimester Early Results) can be done at 10 plus weeks to 13 plus weeks with an [[ultrasound]] of the fetal neck (thicker nuchal skin correlates with higher risk of Down syndrome being present) and two chemicals (analytes), [[pregnancy-associated plasma protein A]] and [[human chorionic gonadotropin]] (pregnancy hormone level itself<ref>{{cite journal | vauthors = Malone FD, Canick JA, Ball RH, Nyberg DA, Comstock CH, Bukowski R, Berkowitz RL, Gross SJ, Dugoff L, Craigo SD, Timor-Tritsch IE, Carr SR, Wolfe HM, Dukes K, Bianchi DW, Rudnicka AR, Hackshaw AK, Lambert-Messerlian G, Wald NJ, D'Alton ME | display-authors = 6 | title = First-trimester or second-trimester screening, or both, for Down's syndrome | journal = The New England Journal of Medicine | volume = 353 | issue = 19 | pages = 2001–2011 | date = November 2005 | pmid = 16282175 | doi = 10.1056/NEJMoa043693 | doi-access = free }}</ref>). It gives an accurate risk profile very early. A second blood screen at 15 to 20 weeks refines the risk more accurately.<ref>{{Cite web |date=2021-08-08 |title=Common Tests During Pregnancy |url=https://www.hopkinsmedicine.org/health/wellness-and-prevention/common-tests-during-pregnancy |access-date=2022-04-29 |website=www.hopkinsmedicine.org |language=en}}</ref> The cost is higher than an "AFP-quad" screen due to the ultrasound and second blood test, but it is quoted to have a 93% pick up rate as opposed to 88% for the standard AFP/QS. This is an evolving standard of care in the United States.<ref name="Carlson2017">{{cite journal | vauthors = Carlson LM, Vora NL | title = Prenatal Diagnosis: Screening and Diagnostic Tools | journal = Obstetrics and Gynecology Clinics of North America | volume = 44 | issue = 2 | pages = 245–256 | date = June 2017 | pmid = 28499534 | pmc = 5548328 | doi = 10.1016/j.ogc.2017.02.004 }}</ref><ref name="Zhang2019">{{cite journal | vauthors = Zhang W, Mohammadi T, Sou J, Anis AH | title = Cost-effectiveness of prenatal screening and diagnostic strategies for Down syndrome: A microsimulation modeling analysis | journal = PLOS ONE | volume = 14 | issue = 12 | pages = e0225281 | date = 2019 | pmid = 31800591 | pmc = 6892535 | doi = 10.1371/journal.pone.0225281 | doi-access = free | bibcode = 2019PLoSO..1425281Z }}</ref><ref name="Common Tests During Pregnancy">{{Cite web |date=2021-08-08 |title=Common Tests During Pregnancy |url=https://www.hopkinsmedicine.org/health/wellness-and-prevention/common-tests-during-pregnancy |access-date=2022-04-28 |website=www.hopkinsmedicine.org |language=en}}</ref>
[[File:Down Syndrome karyotype.png|thumb|Down syndrome karyotype]]

==== Second trimester ====
* MSAFP/quad. screen (four simultaneous blood tests) (maternal serum [[alpha-fetoprotein|AFP]], [[inhibin A]], [[estriol]], and [[Human chorionic gonadotropin|βHCG]]) – elevations, low numbers or odd patterns correlate with neural tube defect risk and increased risks of trisomy 18 or trisomy 21<ref>{{Cite web |title=Quad screen - Mayo Clinic |url=https://www.mayoclinic.org/tests-procedures/quad-screen/about/pac-20394911 |access-date=2022-04-29 |website=www.mayoclinic.org}}</ref>
* Ultrasound either abdominal or transvaginal to assess cervix, placenta, fluid and baby<ref>{{Cite web |title=Prenatal Ultrasound Procedure Information |url=https://my.clevelandclinic.org/health/diagnostics/9704-pregnancy-prenatal-ultrasonography |access-date=2022-04-29 |website=Cleveland Clinic}}</ref>
* Amniocentesis is the national standard for women over 35 or who reach 35 by mid pregnancy or who are at increased risk by family history or prior birth history.<ref name="Common Tests During Pregnancy"/>

==== Third trimester ====
* [[Hematocrit]] (if low, the mother receives iron supplements)<ref>{{Cite web | vauthors = Uscher J |title=Anemia in Pregnancy: Causes, Symptoms, and Treatment |url=https://www.webmd.com/baby/guide/anemia-in-pregnancy |access-date=2022-04-29 |website=WebMD |language=en}}</ref>
* [[Group B Streptococcus]] screen. If positive, the woman receives IV penicillin or ampicillin while in labor—or, if she is allergic to penicillin, an alternative therapy, such as IV clindamycin or IV vancomycin.<ref name="Common Tests During Pregnancy"/>
* Glucose loading test (GLT) – screens for [[gestational diabetes]]; if > 140&nbsp;mg/dL, a [[glucose tolerance test]] (GTT) is administered; a fasting glucose > 105&nbsp;mg/dL suggests gestational diabetes.<ref>{{Cite web |title=Glucose challenge test - Mayo Clinic |url=https://www.mayoclinic.org/tests-procedures/glucose-challenge-test/about/pac-20394277 |access-date=2022-04-29 |website=www.mayoclinic.org |language=en}}</ref>

Most doctors do a sugar load in a drink form of 50 grams of glucose in cola, lime or orange and draw blood an hour later (plus or minus 5 minutes). The standard modified criteria have been lowered to 135 since the late 1980s.<ref>{{Cite web |title=Glucose tolerance test - Mayo Clinic |url=https://www.mayoclinic.org/tests-procedures/glucose-tolerance-test/about/pac-20394296 |access-date=2022-04-29 |website=www.mayoclinic.org |language=en}}</ref>
[[File:Ultrasonography of abdominal pregnancy.jpg|thumb|The result of an ultrasonography: a black and white image that shows a clear view of the interior abdomen]]

==== Fetal assessments ====
[[Image:Scan12weeks.jpg|thumb|A dating [[Obstetric ultrasonography|scan]] at 12 weeks]]
[[Obstetric ultrasonography]] is routinely used for dating the gestational age of a pregnancy from the size of the [[fetus]], determine the number of fetuses and [[placenta]]e, evaluate for an [[ectopic pregnancy]] and first trimester bleeding, the most accurate dating being in first trimester before the growth of the foetus has been significantly influenced by other factors.<ref>{{Cite journal | vauthors = Kansky C, Ramus RM |date=2021-06-15 | veditors = Pierce Jr JG |title=Basic Obstetric Ultrasound: Background, Indications, Contraindications |url=https://emedicine.medscape.com/article/2047305-overview | journal = Medscape }}</ref> Ultrasound is also used for detecting congenital anomalies (or other foetal anomalies) and determining the [[biophysical profile]]s (BPP), which are generally easier to detect in the second trimester when the foetal structures are larger and more developed.<ref>{{cite book | vauthors = DeFrancesco V | chapter = Perinatology. | title = Clinical Engineering Handbook | date = January 2004 | pages = 410–416 | publisher = Academic Press| doi = 10.1016/B978-012226570-9/50102-2 | isbn = 978-0-12-226570-9 }}</ref>

[[X-ray]]s and [[computerized tomography]] (CT) are not used, especially in the first trimester, due to the [[ionizing radiation]], which has [[teratogen]]ic effects on the foetus.<ref>{{cite journal | vauthors = Shaw P, Duncan A, Vouyouka A, Ozsvath K | title = Radiation exposure and pregnancy | journal = Journal of Vascular Surgery | volume = 53 | issue = 1 Suppl | pages = 28S–34S | date = January 2011 | pmid = 20869193 | doi = 10.1016/j.jvs.2010.05.140 | series = Radiation Safety in Vascular Surgery | doi-access = free }}</ref> No effects of [[magnetic resonance imaging]] (MRI) on the foetus have been demonstrated,<ref>{{cite journal | vauthors = Alorainy IA, Albadr FB, Abujamea AH | title = Attitude towards MRI safety during pregnancy | journal = Annals of Saudi Medicine | volume = 26 | issue = 4 | pages = 306–309 | year = 2006 | pmid = 16885635 | pmc = 6074503 | doi = 10.5144/0256-4947.2006.306 }}</ref> but this technique is too expensive for routine observation. Instead, [[obstetric ultrasonography]] is the imaging method of choice in the first trimester and throughout the pregnancy, because it emits no [[radiation]], is portable, and allows for realtime imaging.<ref>{{cite book | vauthors = Herbst MK, Tafti D, Shanahan MM | chapter =Obstetric Ultrasound |date=2022 | chapter-url=http://www.ncbi.nlm.nih.gov/books/NBK470450/ | title = StatPearls |place=Treasure Island (FL) |publisher=StatPearls Publishing |pmid=29261880 |access-date=2022-04-29 }}</ref>

The safety of frequent ultrasound scanning has not been confirmed. Despite this, increasing numbers of women are choosing to have additional scans for no medical purpose, such as gender scans, 3D and 4D scans.<ref>{{cite journal | vauthors = Edvardsson K, Small R, Persson M, Lalos A, Mogren I | title = 'Ultrasound is an invaluable third eye, but it can't see everything': a qualitative study with obstetricians in Australia | journal = BMC Pregnancy and Childbirth | volume = 14 | issue = 1 | pages = 363 | date = October 2014 | pmid = 25336335 | pmc = 4287579 | doi = 10.1186/1471-2393-14-363 | doi-access = free }}</ref> A normal gestation would reveal a [[gestational sac]], [[yolk sac]], and [[fetal pole]].<ref>{{cite book | chapter = Obstetric Imaging | veditors = Weissleder R, Harisinghani MG, Wittenberg J, Chen JW |title=Primer of Diagnostic Imagin |date=2011 | pages = 533–574 |publisher=Mosby |location=St. Louis, Mo. |isbn=978-0-323-06538-2 |edition=5th | doi = 10.1016/B978-0-323-06538-2.00010-X }}</ref>

The [[Gestational age (obstetrics)|gestational age]] can be assessed by evaluating the mean gestational sac diameter (MGD) before week 6, and the crown-rump length after week 6. [[Multiple gestation]] is evaluated by the number of [[placenta]]e and [[amniotic sac]]s present.<ref>{{Cite web | vauthors = Khan AN, Sabih D, Sabih A |date=2021-04-26 |title=Early Pregnancy Loss (Embryonic Demise) Imaging: Practice Essentials, Ultrasonography |url=https://emedicine.medscape.com/article/403208-overview}}</ref>

Other tools used for assessment include:
* Fetal screening is used to help assess the viability of the fetus, as well as congenital abnormalities.<ref>{{Cite journal | vauthors = Marino T | veditors = Ramus RM |date=2021-06-14 |title=Prenatal Diagnosis for Congenital Malformations and Genetic Disorders: Practice Essentials, Noninvasive Techniques, Invasive Techniques |url=https://emedicine.medscape.com/article/1200683-overview | journal = Medscape }}</ref>
* Fetal [[karyotype]] can be used for the screening of genetic diseases. This can be obtained via [[amniocentesis]] or [[chorionic villus sampling]] (CVS<ref>{{Cite web |title=Chorionic villus sampling - Mayo Clinic |url=https://www.mayoclinic.org/tests-procedures/chorionic-villus-sampling/about/pac-20393533 |access-date=2022-04-29 |website=www.mayoclinic.org}}</ref>)
* Foetal [[haematocrit]] for the assessment of foetal [[anemia]], Rh isoimmunization, or [[hydrops fetalis|hydrops]] can be determined by [[percutaneous umbilical blood sampling]] (PUBS), which is done by placing a needle through the abdomen into the [[uterus]] and taking a portion of the [[umbilical cord]].<ref>{{cite book | vauthors = Gomella TL, Cunningham MD, Eyal FG, Tuttle DJ |title=Fetal Assessment |date=2013 |url=http://accesspediatrics.mhmedical.com/content.aspx?aid=1107523894 |work=Neonatology: Management, Procedures, On-Call Problems, Diseases, and Drugs |edition=7 |place=New York, NY |publisher=McGraw-Hill Education |access-date=2022-04-29 }}</ref>
* Fetal lung maturity is associated with how much [[surfactant]] the fetus is producing. Reduced production of surfactant indicates decreased lung maturity and is a high risk factor for [[infant respiratory distress syndrome]].<ref>{{cite book | vauthors = Jobe AH | chapter = Fetal lung maturation and the respiratory distress syndrome. | title = Fetal Physiology and Medicine | edition = Second | date = January 1984 | pages = 317–351 | publisher = Butterworth-Heinemann | doi = 10.1016/B978-0-407-00366-8.50016-2 | isbn = 978-0-407-00366-8 }}</ref> Typically a [[lecithin]]:[[sphingomyelin]] ratio greater than 1.5 is associated with increased lung maturity.
* [[Nonstress test]] (NST) for fetal heart rate<ref>{{Cite web |title=Nonstress test - Mayo Clinic |url=https://www.mayoclinic.org/tests-procedures/nonstress-test/about/pac-20384577 |access-date=2022-04-29 |website=www.mayoclinic.org}}</ref>
* [[Oxytocin challenge test]]