Obstetrics
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'''Obstetrics''' (from the [[Latin]] ''obstare'', "to stand by") is the [[surgery|surgical]] specialty dealing with the care of a woman and her offspring during [[pregnancy]], [[childbirth]] and the [[puerperium]] (the period shortly after birth). [[Midwifery]] is the equivalent non-surgical specialty. Most obstetricians are also [[gynaecology|gynaecologists]]. See ''[[Obstetrics and gynaecology]]''.
The average gestational period for humans is 40 weeks by [[gestational age]] and 38 weeks by fertilization age. This is divided into three [[trimester]]s.
[[Veterinary obstetrics]] is the same concept for [[Veterinary medicine]].
== Antenatal care ==
In obstetric practice, an obstetrician or midwife sees a pregnant woman on a regular basis to check the progress of the pregnancy, to verify the absence of ex-novo disease, to monitor the state of preexisting disease and its possible effect on the ongoing pregnancy. A woman's schedule of antenatal appointment varies according to the presence of risk factors, such as [[diabetes]], and local resources.
Some of the clinically and statistically more important risk factors that must be systematically excluded, especially in advancing pregnancy, are [[pre-eclampsia]], abnormal placentation, abnormal fetal presentation and [[Intrauterine Growth Restriction]].
For example, to identify [[pre-eclampsia]], blood-pressure and albuminuria (level of [[urine]] protein) are checked at every opportunity.
[[Placenta praevia]] '''must''' be excluded (PP = low lying placenta that, at least partially, obstructs the birth canal and therefore warrants elective caesarean delivery); this can only be achieved with the use of an [[obstetric ultrasonography|ultrasound]] scan. However, early placenta praevia is not alarming; this is because as the uterus grows along the pregnancy, the placenta may still move away. A placenta praevia is of clinical significance as from the 28th week of gestation. The current management includes a caesarean section. The type of caesarean section is determined by the position (anterior or posterior) of the placenta.
In late pregnancy fetal presentation must be established: cephalic presentation (head first) is the norm but the fetus may present feet-first or buttocks-first ([[Breech birth|breech]]), side-on (transverse), or at an angle (oblique presentation).
[[Intrauterine Growth Restriction]] is a general designation, where the fetus is smaller than expected when compared to its gestational age (in this case fetal growth parameters show a tendency to drop off from the 50th percentile eventually falling below the 10th percentile, when plotted on a fetal growth chart). Causes can be intrinsic (to the fetus) or extrinsic (maternal or placental problems).
== Signs ==
[[Image:PregnancyAnatomicalModel.jpg|thumb|Anatomical model of a human pregnancy]]
=== Trimesters ===
'''First trimester''': elevated β-hCG (human chorionic gonadotrophin) of up to 100,000 mIU/mL by 10 weeks GA is thought to contribute to [[morning sickness]], fatigue, [[mood swing]]s and food cravings. The symptoms can last through 12 to 16 weeks of gestation.
'''Second trimester''': The abdomen shows an obvious swelling arising from the pelvis, starting the "obvious phase" of pregnancy. [[Hyperpigmentation]], including [[linea nigra]], may appear.
'''Third trimester''': The mother may experience [[back pain|backaches]] due to increased strain. Typically, the curvature of the spine is changed as pregnancy evolves in order to counteract the change in weight distribution. The mother may also suffer mild [[urinary incontinence]] due to pressure on the bladder by the pregnant uterus, as well as [[heartburn]](due to compression of the stomach).
=== Overall ===
* Bluish discoloration of vagina and cervix (Chadwick's sign)
* Softening and cyanosis of cervix after 4 weeks (Goodell's sign)
* Softening of uterus after 6 weeks (Hegar's or Ladin's sign)
* [[Breast]] swelling and tenderness
* [[Linea nigra]] from umbilicus to pubis
* [[Telangiectasias]]
* [[Palmar erythema]]
* [[Amenorrhea]]
* [[Nausea]] and [[vomit]]ing
* Breast pain
* Fetal movement
* [[Sciatica]] (Pain caused by compression of the [[sciatic nerve]])
== Maternal physiology ==
During pregnancy, the woman undergoes many [[physiology|physiological]] changes, which are entirely normal, including [[cardiovascular]], [[hematology|hematologic]], [[metabolism|metabolic]], [[renal]] and [[Respiration (physiology)|respiratory]] changes that become very important in the event of complications.
=== Cardiovascular ===
The woman is the sole provider of nourishment for the [[embryo]] and later, the [[fetus]], and so her [[Blood plasma|plasma]] and blood volume slowly increase by 40-50% over the course of the pregnancy to accommodate the changes. This results in overall [[vasodilation]], an increase in [[heart rate]] (15 beats/min more than usual), stroke volume, and [[cardiac output]]. Cardiac output increases by about 50%, mostly during the first trimester. The systemic vascular resistance also drops due to the smooth muscle relaxation caused by elevated progesterone, leading to a fall in blood pressure. Diastolic [[blood pressure]] consequently decreases between 12-26 weeks, and increases again to prepregnancy levels by 36 weeks. If the blood pressure remains abnormal beyond 36 weeks, the woman should be investigated for [[pre-eclampsia]], a condition that precedes [[eclampsia]].
=== Hematology ===
* The [[Blood plasma|plasma]] volume increases by 50% and the red blood cell volume increases only by 20-30%.
* Consequently, the [[hematocrit]] decreases.
* White blood cell count increases and may peak at over 20 mil/mL in stressful conditions.
* Decrease in platelet concentration to a minimal normal values of 100-150 mil/mL
* The pregnant woman also becomes [[hypercoagulable]] due to increased [[liver]] production of coagulation factors, mainly [[fibrinogen]] and [[factor VIII]].
=== Metabolism ===
During pregnancy, both [[protein metabolism]] and [[carbohydrate metabolism]] are affected. One [[kilogram]] of extra [[protein]] is deposited, with half going to the [[fetus]] and [[placenta]], and another half going to [[uterus|uterine]] contractile proteins, [[breast gland]]ular tissue, plasma protein, and [[hemoglobin]].
=== Nutrition ===
* Increased caloric requirement by 300 kcal/day
* Gain of 20 to 30 lb (10 to 15 kg)
* Increased protein requirement to 70 or 75 g/day
* Increased [[folate]] requirement from 0.4 to 0.8 mg/day (important in preventing [[neural tube defects]])
All patients are advised to take [[prenatal vitamins]] to compensate for the increased nutritional requirements. The use of Omega 3 fatty acids supports mental and visual development of infants.<ref name="titleOmega-3 least known of pregnancy Big 3">{{cite web |url=http://www.nutraingredients-usa.com/news/ng.asp?n=70645&m=1NIU918&c=dhtelyatuhgpyxm+ |title=Omega-3 least known of pregnancy "Big 3" |accessdate=2008-01-01 |format= |work=}}</ref> Choline supplementation of research mammals supports mental development that lasts throughout life.<ref name="pmid10531535">{{cite journal |author=Tees RC, Mohammadi E |title=The effects of neonatal choline dietary supplementation on adult spatial and configural learning and memory in rats |journal=Dev Psychobiol |volume=35 |issue=3 |pages=226–40 |year=1999 |pmid=10531535|doi=10.1002/(SICI)1098-2302(199911)35:3<226::AID-DEV7>3.0.CO;2-H}}</ref>
=== Gastrointestinal ===
* nausea and vomiting ("[[morning sickness]]") may be due to elevated [[B-hCG]], which should resolve by 14 to 16 weeks
* prolonged gastric empty time
* decreased gastroesophageal sphincter tone, which can lead to [[acid reflux]]
* decreased colonic motility, which leads to increased water absorption and [[constipation]]
=== Renal ===
* Increase in kidney and ureter size
* Increased [[glomerular filtration rate]] (GFR) by 50%, which subsides around 20 weeks [[postpartum]]
** Decreased BUN ([[blood urea nitrogen]]) and [[creatinine]], and glucosuria (due to saturated tubular reabsorption)
*** Persistent glucosuria can suggest [[gestational diabetes]]
* Increased [[renin-angiotensin system]], causing increased [[aldosterone]] levels
** Plasma [[sodium]] does not change because this is offset by the increase in GFR
=== Pulmonary ===
* Increased [[tidal volume]] (30-40%)
* Decreased [[total lung capacity]] (TLC) by 5% due to elevation of diaphragm from uteral compression
* Decreased [[expiratory reserve volume]]
* Increased [[minute ventilation]] (30-40%) which causes a decrease in PaCO2 and a compensated [[respiratory alkalosis]]
All of these changes can contribute to the [[dyspnea]] (shortness of breath) that a pregnant woman may experience.
=== Endocrine ===
* Increased [[estrogen]], which is mainly produced in the [[placenta]]
** Fetal well being is associated with maternal estrogen levels
** Causes an increase in [[thyroxine-binding globulin]] (TBG)
* Increased [[human chorionic gonadotropin]] (β-hCG), which is produced by the placenta. This maintains [[progesterone]] production by the [[corpus luteum]]
* [[Human placental lactogen]] (hPL) is produced by the placenta and ensures nutrient supply to the fetus. It also causes [[lipolysis]] and is an [[insulin]] antagonist, which is a diabetogenic effect.
* Increased progesterone production, first by corpus luteum and later by the placenta. Its main course of action is to relax smooth muscle.
* Increased [[prolactin]]
* Increased [[alkaline phosphatase]]
=== Musculoskeleton and dermatology ===
* Lower back pain due to a shift in gravity
* Increased estrogen can cause [[spider angiomata]] and [[palmar erythema]]
* Increase [[melanocyte]]-stimulating hormone (MSH) can cause hyperpigmentation of nipples, umbilicus, abdominal midline ([[linea nigra]]), perineum, and face (melasma or chloasma)
===Others===
* [[Edema]], or swelling, of the feet is common during pregnancy, partly because the enlarging uterus compresses veins and lymphatic drainage from the legs.
== Prenatal care ==
{{main|Prenatal care}}
Prenatal care is important in screening for various complications of pregnancy. This includes routine office visits with physical exams and routine lab tests:
=== First trimester ===
* [[complete blood count]] (CBC)
* [[blood type]] (blood transfusion may be needed in an emergency)
* general [[antibody]] screen ([[Coombs test#indirect Coombs test|indirect Coombs test]]) for [[HDN]]
** Rh D negative antenatal patients should receive RhoGam at 28 weeks to prevent Rh disease.
* [[Rapid plasma reagent]] (RPR) which screens for [[syphilis]]
* [[Rubella]] antibody screen
* [[Hepatitis B]] surface antigen
* [[Gonorrhea]] and [[Chlamydia (bacterium)|Chlamydia]] culture
* [[Mantoux test|PPD]] for [[tuberculosis]]
* [[Pap smear]]
* [[Urinalysis]] and culture
* [[HIV]] screen
* [[Group B Streptococcus]] screen -- will receive IV penicillin if positive (if mother is allergic, alternative therapies include IV clindamycin or IV vancomycin)
=== Second trimester ===
* MSAFP/triple screen (maternal serum [[alpha-fetoprotein]]) - elevation correlated with neural tube defects and decrease correlated with Down's syndrome
* ultrasound
* amniocentesis in older patients
=== Third trimester ===
* hematocrit (if low, mother will receive iron supplementation)
* [[glucose loading test]] (GLT) - screens for gestational diabetes; if > 140 mg/dL, a [[glucose tolerance test]] (GTT) is administered; a fasting glucose > 105 mg/dL suggests gestational diabetes.
== Complications ==
''See'' [[Complications of Pregnancy]]
=== Fetal assessments ===
;Common:
* [[Obstetric ultrasonography|ultrasound]] is used for many functions:
** Dating the gestational age of a pregnancy, most accurate in first trimester
** Detecting fetal anomalies in the second trimester
** [[biophysical profile]]s (BPP)
** Blood flow velocity in [[umbilical cord]] -- decrease/absence/reversal or diastolic blood flow in the umbilical artery is worrisome.
** Congenital anomalies can be diagnosed with second trimester ultrasound
* Fetal [[karyotype]] for the screening of genetic diseases can be obtained via [[amniocentesis]] or [[chorionic villus sampling]] (CVS)
;Uncommon:
* Fetal [[hematocrit]] for the assessment of fetal [[anemia]], Rh isoimmunization, or [[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]].
* 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 [[neonatal respiratory distress syndrome]] (NRDS). Typically a [[lecithin]]:[[sphingomyelin]] ratio greater than 1.5 is associated with increased lung maturity.
* [[Nonstress test]] (NST) for fetal heart rate
* [[Oxytocin challenge test]]
== Induction ==
Reasons to induce include:
# [[pre-eclampsia]]
# [[IUGR]]
# diabetes
# other general medical condition, such as [[renal disease]]
# "postdates" - the pregnancy has lasted longer than 41 weeks after the last menstrual period
Induction may occur any time after 34 weeks of gestation if the risk to the fetus or mother is greater than the risk of delivering a premature fetus regardless of lung maturity.
If a woman does not eventually labour by 41-42 weeks, induction may be performed, as the placenta may become unstable after this date.
Induction may be achieved via several methods:
# [[pessary]] of ''Prostin'' cream, [[prostaglandin]] E<sub>2</sub>
# l or oral administration of misoprostol
# cervical insertion of a 30-mL Foley catheter
# rupturing the amniotic membranes
# intravenous infusion of synthetic [[oxytocin]] (Pitocin or Syntocinon)
== Labor ==
During labor itself, the obstetrician/doctor/intern/medical student under supervision may be called on to do a number of things:
# monitor the progress of labor, by reviewing the nursing chart, performing vaginal examination, and assessing the trace produced by a fetal monitoring device (the [[cardiotocograph]])
# accelerate the progress of labor by infusion of the hormone [[oxytocin]]
# provide pain relief, either by [[nitrous oxide]] (nowadays uncommon, at least in the [[United States|U.S.]]), [[opiates]], or by [[local anesthesia|epidural anesthesia]] done by [[anesthesiology|anaesthestists]], an anesthesiologist, or a [[nurse anesthetist]].
# surgically assisting labor, by forceps or the Ventouse (a suction cap applied to the fetus' head)
# [[Caesarean section]], if vaginal delivery is decided against or appears too difficult. Caesarean section can either be elective, that is, arranged before labor, or decided during labor as an alternative to hours of waiting. True "emergency" Cesarean sections (where minutes count) include abruptio placenta, and are more common in mulitgravid patients, or patients attempting a VBAC (Vaginal Birth After Caeserean section).
== Antenatal ==
During the time immediately after birth both baby as well as mother are hormonally cued to bond, the mother through the release of [[oxytocin]] a hormone also released with [[breastfeeding]].
== Emergencies in obstetrics ==
The main emergencies include:
* [[Ectopic pregnancy]] is when an embryo implants in the Fallopian tube or (rarely) on the ovary or inside the peritoneal cavity. This may cause massive internal bleeding.
* [[Pre-eclampsia]] is a disease which is defined by a combination of signs and symptoms that are related to maternal hypertension. The cause is unknown, and markers are being sought to predict its development from the earlist stages of pregnancy.
Some unknown factors cause vascular damage in the [[endothelium]], causing [[hypertension]] and [[proteinuria]]. If severe, it progresses to fulminant pre-eclampsia, with headaches, epigastric pain and visual disturbances. This is a prelude to ''eclampsia'', where a convulsion occurs, which can be fatal.
* [[Placental abruption]] where the patient can bleed to death if not managed appropriately.
* [[Shoulder dystocia]] where one of the fetus' shoulders becomes stuck during vaginal birth, especially in macrosomic babies of diabetic mothers.
== Imaging, monitoring and care ==
In present society, medical science has developed a number of procedures to monitor pregnancy.
===Antenatal record===
On the first visit to her [[obstetrician]] or [[midwife]], the pregnant woman is asked to carry out the [[antenatal record]], which constitutes a [[medical history]] and [[physical examination]].
On subsequent visits, the [[gestational age]] (GA) is rechecked with each visit.
[[Symphysis-fundal height]] (SFH; in cm) should equal gestational age after 20 weeks of gestation, and the fetal growth should be plotted on a curve during the antenatal visits.
The fetus is palpated by the midwife or obstetrician using [[Leopold maneuver]] to determine the position of the baby.
[[Blood pressure]] should also be monitored, and may be up to 140/90 in normal pregnancies. High blood pressure indicates [[hypertension]] and possibly [[pre-eclampsia]], if severe swelling ([[edema]]) and spilled protein in the urine are also present.
[[Fetal screening]] is also used to help assess the viability of the fetus, as well as congenital problems. [[Genetic counseling]] is often offered for families who may be at an increased risk to have a child with a genetic condition.
[[Amniocentesis]] at around the 20th week is sometimes done for women 35 or older to check for [[Down's Syndrome]] and other [[chromosome]] abnormalities in the fetus.
Even earlier than amniocentesis is performed, the mother may undergo the [[triple test]], [[nuchal translucency|nuchal screening]], [[nasal bone]], [[alpha-fetoprotein]] screening and [[Chorionic villus sampling]], also to check for disorders such as Down Syndrome. Amniocentesis is a prenatal genetic screening of the fetus, which involves inserting a needle through the mother's abdominal wall and uterine wall, to extract fetal DNA from the amniotic fluid. There is a risk of miscarriage and fetal injury with amniocentesis because it involves penetrating the uterus with the baby still in utero.
===Imaging===
[[Image:Scan12weeks.jpg|thumb|A dating [[Obstetric ultrasonography|scan]] at 12 weeks]]
Imaging is another important way to monitor a pregnancy. The mother and [[fetus]] are also usually imaged in the first trimester of pregnancy. This is done to predict problems with the mother; confirm that a pregnancy is present inside the [[uterus]]; estimate the [[gestational age]]; determine the number of fetuses and [[placenta]]e; evaluate for an [[ectopic pregnancy]] and first trimester bleeding; and assess for early signs of anomalies.
[[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 fetus. Instead, [[obstetric ultrasonography|ultrasound]] 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.
Ultrasound imaging may be done at any time throughout the pregnancy, but usually happens at the 12th week (dating scan) and the 20th week (detailed scan).
A normal gestation would reveal a [[gestational sac]], [[yolk sac]], and [[fetal pole]].
The [[gestational age]] can be assessed by evaluating the [[mean gestation 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.
Pregnancy has different cultural aspects related to the perception of the body, the relationship with partner and to the meaning of the event.
== Terms and definitions ==
* ''embryo'' - conceptus between time of fertilization to 10 weeks of gestation
* ''fetus'' - from 10 weeks of gestation to time of birth
* ''infant'' - time of birth to 1 year of age
* ''gestational age'' - time from first day of last menstrual period (LMP) up to present
* ''first trimester'' - up to 14 weeks of gestation
* ''second trimester'' - 14 to 28 weeks of gestation
* ''third trimester'' - 28 weeks to delivery
* ''viability'' - 24 weeks by definition, age at which fetus is believed to have all organs formed (though immature)
* ''previable infant'' - delivered prior to 24 weeks
* ''preterm infant'' - delivered between 24-37 weeks
* ''term infant'' - delivered between 37-42 weeks
* ''gravidity (G)'' - number of times a woman has been pregnant
* ''parity (P)'' - number of pregnancies with a birth/abortion beyond 20 weeks GA or an infant weighing more than 500 g
* ''Ga Pw-x-y-z'' - a = number of pregnancies, w = number of term births, x = number of preterm births, y = number of abortions (spontaneous or therapeutic), z = number of living children; for example, G4P1-2-1-3 means the woman had a total of 4 pregnancies, of which 1 is of term, 2 are preterm, 1 miscarriage or therapeutic abortion, and 3 total living children (1 term + 2 preterm).
==Salary==
The salary of an obstetrician varies from country to country:
{| class="wikitable"
!Country
!Annual salary ($)
|-
|United Kingdom
| 118,000 <ref>[http://www.salaryexpert.com/index.cfm?FuseAction=Free_Salary_Intl.Report&job=2934&area=942&Action=Search salaryexpert.com] Presumed the value is in GBP, then by Google December 18, 2007: 117 999 British pounds = 239 832.968 U.S. dollars</ref>
|-
|[[United Arab Emirates]]
|228,190 <ref>[http://www.salaryexpert.com/index.cfm?FuseAction=Free_Salary_Intl.Report&job=2934&area=941&Action=Searcha=942&Action=Search salaryexpert.com] Presumed the value is in AED, then by Google December 18, 2007: 838 051 British pounds = 1.70333866 million U.S. dollars</ref>
|}
==See also==
*[[List of obstetric topics]]
*[[Gynecology]]
*[[Home birth]]
*[[Maternal health]]
*[[Midwifery]]
*[[Obstetric ultrasonography]]
*[[Puerperum]]
== References ==
{{reflist}}
=== Further reading ===
* {{cite journal|journal=Medical History|date=July 1987|volume=31|issue=3|pages=333–348|title=A provincial surgeon and his obstetric practice: Thomas W. Jones of Henley-in-Arden, 1764–1846|author=J Lane|url=http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1139744|pmid=3306222}}
==External links==
*[http://www.OBGYN.net OBGYN.net resource portal ] on Obstetrics and Gynecology for patients and medical professionals
* [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?itool=abstractplus&db=pubmed&cmd=Retrieve&dopt=abstractplus&list_uids=10531535 Prenatal Choline improves research mammals lifetime mental ability]
* [http://www.nutraingredients-usa.com/news/ng.asp?n=70645&m=1NIU918&c=dhtelyatuhgpyxm Omega 3 fatty acid supports mental and visual development of infants]
* [http://www.doctor.vg/forumdisplay.php?f=16 Obstetrics Forums]
* [http://www.ingenious.org.uk/See/Medicineandhealth/Obstetricsgynaecologyandcontraception/ Ingenious]: archive of historical images related to obstetrics, gynaecology, and contraception.
*[http://www.obgynhealth.net OBGYNHealth.net]
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