Obstetrics

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For the medical specialty, see Obstetrics and gynaecology.

Obstetrics is the medical profession that deals with pregnancy, childbirth, and the postpartum period, chiefly at risk situations requiring surgical interventions. Midwifery is an associated health profession. As a medical specialty, obstetrics is combined with gynaecology under the discipline known as obstetrics and gynaecology (OB/GYN).

Main areas[edit]

Prenatal care[edit]

Main article: 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[edit]

Genetic screening for downs syndrome (trisomy 21) and trisomy 18 the national standard in the United States is rapidly evolving away from the AFP-Quad screen for downs syndrome- done typically in the second trimester at 16–18 weeks. 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 (thick skin is bad) and two chemicals (analytes) PAPP-A and βHCG (pregnancy hormone level itself). It gives an accurate risk profile very early. A second blood screen at 15 to 20 weeks refines the risk more accurately. 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.

Second trimester[edit]

  • MSAFP/quad. screen (four simultaneous blood tests) (maternal serum AFP, inhibin A, estriol, & βHCG) - elevations, low numbers or odd patterns correlate with neural tube defect risk and increased risks of trisomy 18 or trisomy 21
  • Ultrasound either abdominal or trannsvaginal to assess cervix, placenta, fluid and baby
  • Amniocentesis is the national standard (in what country) for women over 35 or who reach 35 by mid pregnancy or who are at increased risk by family history or prior birth history.

Third trimester[edit]

  • [Hematocrit] (if low, the mother receives iron supplements)
  • 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.
  • 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.

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

Induction[edit]

Main article: Induction (birth)

Induction is a method of artificially or prematurely stimulating labour in a woman. Reasons to induce can include pre-eclampsia, placental malfunction, intrauterine growth retardation,[1] and other various general medical conditions, such as renal disease. 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.

Induction may be achieved via several methods:

Labor[edit]

Main article: Childbirth

During labor, the obstetrician carries out the following tasks:

  • 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
  • Surgically assisting labor, by forceps or the Ventouse (a suction cap applied to the fetus' head)
  • Caesarean section, if there is an associated risk with vaginal delivery, as such fetal or maternal compromise supported by evidence and literature. 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 include abruptio placenta, and are more common in multigravid patients, or patients attempting a Vaginal Birth After Caeserean section (VBAC).

Antenatal record[edit]

Fetal screening is 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, which is usually performed between 15 and 20 weeks,[2] to check for Down syndrome, other chromosome abnormalities or other conditions in the fetus, is sometimes offered to women who are at increased risk due to factors such as older age, previous affected pregnancies or family history. Amniocentesis, and other invasive investigations such as chorionic villus sampling, is not performed in the UK as frequently as it is in other countries, and in the UK, advanced maternal age alone is not an indication for such an invasive procedure.

Even earlier than amniocentesis is performed, the mother may undergo the triple test, nuchal screening, nasal bone, alpha-fetoprotein screening, Chorionic villus sampling, and 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[edit]

A dating 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 placentae; evaluate for an ectopic pregnancy and first trimester bleeding; and assess for early signs of anomalies.

X-rays and computerized tomography (CT) are not used, especially in the first trimester, due to the ionizing radiation, which has teratogenic effects on the fetus. No effects of magnetic resonance imaging (MRI) on the fetus have been demonstrated,[3] 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.

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).

The safety of frequent ultrasound scanning has not be 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.

A normal gestation would reveal a gestational sac, yolk sac, and fetal pole. The 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 placentae and amniotic sacs present.

Fetal assessments[edit]

Obstetric ultrasonography is routinely used for dating the gestational age of a pregnancy from the size of the fetus, the most accurate dating being in first trimester before the growth of the fetus has been significantly influenced by other factors. Ultrasound is also used for detecting congenital anomalies (or other fetal anomalies) and determining the biophysical profiles (BPP), which are generally easier to detect in the second trimester when the fetal structures are larger and more developed. Specialised ultrasound equipment can also evaluate the blood flow velocity in the umbilical cord, looking to detect a decrease/absence/reversal or diastolic blood flow in the umbilical artery.

Other tools used for assessment include:

Complications and emergencies[edit]

The main emergencies include:

  • Ectopic pregnancy is when an embryo implants in the uterine (Fallopian) tube or (rarely) on the ovary or inside the peritoneal cavity. This may cause massive internal bleeding.
  • Pre-eclampsia is a disease 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 earliest stages of pregnancy. Some unknown factors cause vascular damage in the endothelium, causing hypertension. If severe, it progresses to eclampsia, where seizures occur, which can be fatal. Preeclamptic patients with the HELLP syndrome show liver failure and Disseminated intravascular coagulation (DIC). The only treatment is to deliver the fetus. Women may still develop pre-eclampsia following delivery.
  • Placental abruption is where the placenta detaches from the uterus and the woman and fetus can bleed to death if not managed appropriately.
  • Fetal distress where the fetus is getting compromised in the uterine environment.
  • Shoulder dystocia where one of the fetus' shoulders becomes stuck during vaginal birth. There are many risk factors, including macrosmic (large) fetus, but many are also unexplained.
  • Uterine rupture can occur during obstructed labor and endanger fetal and maternal life.
  • Prolapsed cord can only happen after the membranes have ruptured. The umbilical cord delivers before the presenting part of the fetus. If the fetus is not delivered within minutes, or the pressure taken off the cord, the fetus dies.
  • Obstetrical hemorrhage may be due to a number of factors such as placenta previa, uterine rupture or tears, uterine atony, retained placenta or placental fragments, or bleeding disorders.
  • Puerperal sepsis is an ascending infection of the genital tract. It may happen during or after labour. Signs to look out for include signs of infection (pyrexia or hypothermia, raised heart rate and respiratory rate, reduced blood pressure), and abdominal pain, offensive lochia (blood loss) increased lochia, clots, diarrhea and vomiting.

Intercurrent diseases[edit]

In addition to complications of pregnancy that can arise, a pregnant woman may have intercurrent diseases, that is, other diseases or conditions (not directly caused by the pregnancy) that may become worse or be a potential risk to the pregnancy.

Postnatal care[edit]

Further information: Postnatal

Postnatal care is care provided to the mother following parturition.

A woman in the Western world who is delivering in a hospital may leave the hospital as soon as she is medically stable and chooses to leave, which can be as early as a few hours postpartum, though the average for spontaneous vaginal delivery (SVD) is 1–2 days, and the average caesarean section postnatal stay is 3–4 days.

During this time the mother is monitored for bleeding, bowel and bladder function, and baby care. The infant's health is also monitored.

Certain things must be kept in mind as the physician proceeds with the post-natal care.

  1. General condition of the patient.
  2. Check for vital signs (pulse, blood pressure, temperature, respiratory rate, (pain) at times)
  3. Palor?
  4. Edema?
  5. Dehydration?
  6. Fundus (height following parturition, and the feel of the fundus) (Per abdominal examination)
  7. If an episiotomy or a C-section was performed, check for the dressing. Intact, pus, oozing, haematomas?
  8. Lochia (colour, amount, odour)?
  9. Bladder (keep the patient catheterized for 12 hours following local anaesthesia and 24–48 hours after general anaesthesia) ? (check for bladder function)
  10. Bowel movements?
  11. More bowel movements?
  12. Follow up with the neonate to check if they are healthy.

See also[edit]

References[edit]

  1. ^ Wagner, Marsden. Born in the USA: How a Broken Maternity System Must Be Fixed to Put Women and Children First. Berkeley: University of California Press, 2006. Print.
  2. ^ http://www.medicinenet.com/amniocentesis/article.htm
  3. ^ Ibrahim A. Alorainy, Fahad B. Albadr, Abdullah H. Abujamea (2006). "Attitude towards MRI safety during pregnancy". Ann Saudi Med 26 (4): 306–9. PMID 16885635. 
  4. ^ a b Page 264 in: Gresele, Paolo (2008). Platelets in hematologic and cardiovascular disorders: a clinical handbook. Cambridge, UK: Cambridge University Press. ISBN 0-521-88115-3.