Obstetrics - MTB Flashcards
Pregnancy
- suggest in patient w/ amenorrhea, enlargment of uterus and + urinary B-hCG
- confirmed w/ gestational sac, fetal heart motion, fetal heart sounds, and fetal movement
Presence of gestational sac
- seen by transvaginal U/S at 4-5 weeks
- corresponds to B-hCG level of 1500 mIU/mL
Fetal heart motion
- seen by U/S at 5-6 weeks
Fetal heart sounds
- seen by U/S at 8 - 10 weeks
Fetal movements
- felt by examining physician after 20 wees
Gravidity
number of pregnancies
Parity
number of births with gestational age > 24 months
21 y/o primigravida, para 0 (G1P0) presents for her first prenatal visit at 11 weeks gestation, which is confirmed by OB sono. No risk factors. What screening tests will you perform?
- CBC (to check for blood disorders)
- Blood type, Rh and antibody (type and screen, Direct and indirect Coombs)
- Cervical PAP smear
- Urinalysis/ urine culture
- Rubella anibody
- Hep B surface antigen
- RPR
- HIV Elisa
- Cervical culture
Anemia in pregnancy
- look for Hb < 10
- most common cause is Fe deficiency
- WBC > 16K is abnormal
If CBC returns w/ decr Hgb and decreased MCV. Next step?
- Give Fe
- Test for thalassemia is anemia doesn’t improve
If CBC returns w/ decr HgB and increased MCV. Next step?
Give folate to treat possible folate deficiency
If CBC returns w/ thrombocytopenia (< 150K)
- correlate clinically for ITP or HELLP syndrome
Testing for Rh and antibody during pregnancy
- Rh negative mothers may become sensitized (anti-D antibody) which increases risk of erythroblastosis fetalis
- Indirect Coombs test for atypical antibody test
RhoGAM indication
- give to Rh negative mothers at 28 weeks after first rescreening for absence of anti-D antibodies
- given to Rh negative mothers after any procedure (CVS, amniocentesis) and after delivery
Cervical Pap smear during pregnancy
- detects cervical dysplasia or malignancy
Urinalysis/ Urine Cc
- screen for underlying renal disease and infeection
- UCx screen for asymptomatic bacteruris
- always treat ASB to prevent pyelonephritis
ASB: treatment
- Nitrofurantoin (before 30 weeks), Cephalosporins, and Amoxicillin
Rubella antibody
- test in 1st trimester
- Negative rubella IgG ab means increased risk of primary rubell a infection
- DO NOT GIVE RUBELLA IMMUNIZATION DURING PREGNANCY
- Immunize seronegative patients after pregnancy
Hepatitis B surface antigen
- tested in 1st trimester
- Positive HBsAg indicates risk for vertical transmission of HBV
- If (+) HBsAg, order HBVe to check for active infection
Syphillis testing
- done in 1st trimester
- confirm (+) VDRL or RPR with FTA or MHATB
- If (+) confirmatory test, treat with IM penicillin
- If penicllin allergic, desensitize and treat w/ penicillin
HIV ELISA
- test in 1st trimester
- confirm w/ Western blot test (presence of HIV core and envelope
- all babies born to HIV (+) will have HIV antibody due to passive transport of maternal As
- ARVs are not contraindicated in pregnancy`
Chlamydia/Gonorrhea
- cervical culture in 1st trimester
- also treat trichomonas vaginalis
Chlamydia/Gonorrhea: treatment in pregnancy
- PO azithromycin + IM ceftriaxone (treatment of choice)
- Alternative: PO amoxicillin
Bacterial vaginitis: treatment
- PO metronidazole or clindamycin PO
-
Trichomonas vaginalis
- PO metronidazole
Optional tests during 1st trimester
Tuberculosis
Trisomy 21: early testing with PAPP-A and fetal nuchal translucency
Tuberculosis testing in 1st trimester
- optional test
- test for exposure in high risk moms
- (+) test is induration, not erythema
TB management in pregnancy
- If (+) PPD, order CXR to r/o active disease
Treatment for (+) PPD
(+) PDD and (-) CXR: Isoniazide and B6 for 9 mths
(+) PPD and (+) CXR (+) sputum: triple therapy antiTB if sputum stain positive
** Avoid streptomycin in pregnancy for risk of ototoxicity
Trisomy 21: Early testing
- B-hCG
- PAPPA
- Fetal nuchal translucency
- offered to high risk pregnancies (> age of 35 y.o at delivery or women w/ prior hx of Trisomy 21)
Trisomy 21 (Early Testing): Management
(+) screening test is confirmed w/ CVS sampling in 1st trimester
Maternal serum alpha fetoprotein (MS-AFP)
- increases w/ gestational age and is expressed in MoM
- > 2.2 MoM is considered elevated
- < 2. 2 MoM is considered normal
Inhibin A
made by placenta during pregnancy and normally remains constant during 15th - 18th week of pregnancy
- is increased in blood in mothers of fetuses w/ Downs Syndrome
23 y.o F (G3P1 Abortion 1) is seen at 17 weeks gestation. She recently underwent triple marker screen w/ MS-AFP (normal
U/S
- most common cause of abnormal MS-AFP is gestational dating error
Second Trimester Optional Tests
- MS-AFP
- B-hCG
- Add Inhibin A in high risk women (increased sensitivity to 80%)
Increased MS-AFP
- neural tube defect (NTD)
- ventral wall defect
- twin pregnancy
- placental bleeding
- renal disease
- sacrococcygeal teratoma
Decreased MS-AFP
- Trisomy 21 (Down syndrome)
- Trisomy 18
Trisomy 21
- decreased MS-AFP
- decreased estriol
- increased B-hCG
Trisomy 18 (Edward syndrome)
- decreased MS-AFP
- decreased estriol
- decreased B-hCG
Pt has abnormal MS-AFP. Next step?
- Perform U/S to confirm dates
- If dating error, repeat MS-AFP
If normal, repeat MS-AFP is reassuring
If patient has abnormally increased MS-AFP and dates have been confirmed by ultrasound. Next step?
For increased MS-AFP,
- do aminiocentesis for amniotic fluid alpha fetoprotein level and acetylcholintersase activity
- elevated amniotic fluid acetylcholinesterase activity are specific open to NTD
If patient has abnormally decreased MS-AFP and dates have been confirmed by U/S. What’s next step?
For decreased MS-AFP
- amniocentesis for karyotyping
38 y.o F (G2P1) is at 27 weeks gestation. She weighs 227 lbs. She has gained 30 lbs during her pregnancy but reports that most of it is fluid retention. She was diagnosed w/ gestational diabetes during her last pregnancy. Which of the following is the next step in management?
Obtain 1-hr 50 g OGTT (indicated in 24-28 weeks)
– if positive, then patient undergoes confirmatory 3 hr 100g OGTT
What conditions do you test for during 3rd trimester of pregnancy
- Diabetes
- Anemia
- Atypical antibodies
- GBS Screening
Diabetes during pregnancy
- test during 24- 28 weeks of pregnancy
- screening test: 1hr 50g OGTT
- abnormal result is > 140mg/dL
- if (+) screening test: perform 3hr 100g OGTT for glucose intolerance
Anemia during pregnancy
- Do CBC at 24-28 weeks
- Hemoglobin < 10 g / dL = anemia
- Most common cause is Fe deficiency
Atypical antibody testing during pregnancy
- Do Indirect Coombs test
- performed on Rh-negative women to look after anti-D antibodies before giving RhoGAM
- RhoGAM is not indicated in Rh negative women who have developed anti-D antibodies
GBS Screening during pregnancy
- test for vaginal and rectal cx for GBS (35-37 weeks)
- (+) GBS is high risk for neonatal sepsis. Tx with intrapartum IV abx (IV penicillin G, IV clindamycin or erythromycin in penicillin allergic patient)
Confirmatory testing for diabetes in pregnancy
3hr 100g OGTT
Gestational diabetes: diagnosis
After taking 3hr 100 g OGTT
- if plasma glucose > 125 mg/dL at beginning of test - DIABETES MELLITUS
- abnormal plasma measurements > 140 mg/dL at 3 h, 155 mg/dL at 2h, and > 180 mg/dL at 1h
- if > 2 of postglucose load measurements are abnormal, the diagnosis is GESTATIONAL DIABETES
Impaired glucose tolerance after 3hr 100g OGTT
- only 1 postglucose load measurement is abnormal
Indications to give RhoGAM to Rh negative mothers
Give to Rh negative mothers:
- at 28 weeks
- within 72 hrs of delivery
- after miscarriage or abortion
- during amniocentesis or CVS
- with heavy vaginal bleeding
N/V Management during pregnancy
- Doxylamine
- Metoclopramide
- Ondansetron
- Promethazine
- Pyroxidine
Third Trimester Bleeding
- Perform initial management
- Vitals, external fetal monitor, IV fluids - Order lab tests
- CBC, DC w/u, type and crossmatch, obstetric U/S - Further steps in management
- Blood xfusions, foley catheter, vaginal exam to r/o lacerations, scheule delivery if fetus is > 36 weeks
When do you perform speculum exam or digital exam in pregnant patient w/ late trimester vaginal bleeding?
- Digital rectal exam OR speculum exam
MUST DO VAGINAL U/S TO R/O PLACENTA PREVIA
Abruptio Placenta
- sudden onset vaginal bleeding
- severe constant pelvic pain in patient w/ hx of HTN or trauma (e.g. MVA)
- bleeding results from avulsion of anchoring placental villi from lower uterine segment
Feared complication of abruptio placenta
Disseminated intravascular coagulation (DIC)
- release of thromboplastin into the circulation
Placenta Previa
- sudden onset painless bleeding occurs at rest or during activity w/o warning
- includes hx of trauma, coitus, or pelvic examination before bleeding occurs
- occurs when placenta is implanted in lower uterine segment
Complete placenta previa
- the placenta covers the entire os
Incomplete placenta previa
- the placenta partially covers the cervical os
Placenta accreta
- if placental implantation occurs over a previous uterine scare, the villi may invade into the deeper layers of decidua basalis and myometrium
- intractable bleeding may require cesarian hysterectomy
Vasa Previa
- life-threatening for the fetus
- occurs when velamentous cord insertion results in umbilical vessels crossing the placental membranes over cervix
Vasa Previa: Classic triad
- Rupture of membranes
- Painless vaginal bleeding
- Fetal bradycardia
** Emergency C-section is always 1st step management
Uterine rupture
- hx of uterine scar w/ sudden-onset abdominal pain and vaginal bleeding associated w/ loss of electronic fetal heart rate, uterine contractions, and recession of fetal head
Abruptio placenta: risk factors
- Previous abruption
- Hypertension
- Trauma
- Cocaine abuse
Abruptio placenta: diagnosis
Placenta in normal position +/- retroplacental hematoma
Abruptio placenta: management
- Emergent C-section:
- Vaginal delivery > 36 weeks or continued bleeding.
- Admit and observe if bleeding has stopped, vital and fetal heart rate stable, or < 34 weeks
