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Obstetric & Perinatology

  • Beta Strep
  • First trimester bleeding
  • Hyperemesis
  • Infection - Maternal
  • Labor and Delivery Notes
  • Some of this material is particularly dated.

    Beta Strep Management - Antenatal and Infant

    rev. 1994 eg. ancient!


    Infant: Committee on infectious diseases and committee on fetus and the newborn. Guidelines for prevention of group B streptococcal (GB) infections by chemoprophylaxis. Pediatr 1992 Nov ;90(5):775-8.

    Lower Vaginal Culture: 1-2 before 32 w GA

    Culture taken as single swab of lower vagina. Used to be done at 26-28 weeks GA, but CDC has changed to later @35-37 weeks. Some swab anorectum as well.

    a) positive vaginal or urine culture: antibiotics > 4h prior delivery

    b) negative culture: prophylaxis per obstetric indications

    Beta Strep: Management of Infants of Treated Mothers

    a) symptomatic infants: culture & treat as septic (pending cultures)

    b) asymptomatic infants

    1. GA >= 38 weeks: no therapy
    2. GA 34-38 weeks: individualize based on age, other risk factors
    3. GA <=34 weeks: culture and empiric therapy (?IM ampicillin only?)

    First trimester bleeding: ab vs. ectopic

    Common Errors

    1. Always confirm pregnancy with qualitative serum test before initiating major evaluation. History may be unreliable or initial test might be a false positive.


    ultrasound and quantitative B-HCG: at 5w U/S should show sac and B-HCG should be > 6500. Vaginal probe should show sac as early as 3.5 weeks with B-HCG of 15 (?).


    Infection - Maternal

    Labor and Delivery Notes



    Labor Dysfunction


    Ectopic pregnancy management with oral methotrexate

    Molar pregnancy


    Premature Rupture of Membranes

    Thu, Apr 15, 1993 (eg. ancient)

    key decisions: infection vs. immaturity

    The use of pulmonary surfactant (less RDS), and of prostaglandin gel, have yet to be “digested” by the medical literature. Surfactant makes delay of delivery and steroids less important in premies. PG gel makes delay of delivery less important in term infants with an unripe maternal cervix. Beta strep screening also may change management. Factoring these in a rough guess is:

    < 32 weeks: immaturity > infection as cause of mortality.

    > 32 weeks: infection > immaturity as cause of mortality.

    initial considerations and standard evaluation

    a) confirm diagnosis: are membranes ruptured? (see speculum exam)

    b) establish gestational age. Femur length and abdominal circumference are more reliable than HC if oligohydramnios present.

    c) establish if infection present (fever, ?WBC)

    d) establish if fetal distress present

    e) establish if active labor by monitoring and speculum exam

    f) avoid digital exam (see below)

    g) alert pediatrician, consultation if needed (local vs. distal)

    h) establish fetal lung maturity if 32-36 weeks

    These recommendations are of less importance in the surfactant era. We should discuss with our referral center in Green Bay as to whether they would like us to obtain a fluid sample and transport it with the patient.

    (1) PG testing from vaginal pool

    (2) if PG negative L/S ratio on amnio. If do amniocentesis obtain cultures and Gram stain.

    speculum exam

    digital exam

    indications for delivery and associated management issues

    Careful monitoring required, esp. for cord compression.

    C-SXN reserved for usual obstetrical indications, there is increased maternal risk if chorioamnionitis present. May do c-sxn however if suspect very virulent infection.


    Active labor is the most common indication for delivery. Tocolysis doesn’t seem to work in PROM especially with a preterm infant.

    antibiotics (assuming absence of chorioamnionitis)


    fetal distress

    no labor, no choriamnionitis, no fetal distress

    A 48 hour delay in delivery appears to promote fetal lung maturation.

    therapeutic options (general)

    antibiotic regimens for expectant management

    Main benefit is likely for infection with group B strep. Choice of antibiotic, dosing, and mode of administration varies (see also antibiotics in labor, above). The following regimens were described in articles on expectant management.

    induction when indicated (see below)
    monitoring for expectant management

    management by dates

    post-term (>41 weeks)
    term (36-41 weeks)
    pre-term, viable (25-35 weeks)

    Management of PROM without labor in infants from 25-35 weeks is changing quickly. Probably can divide into two subgroups. The following is highly speculative. Antibiotic administration should involve consultation with a perinatologist. These women are likely admitted and/or transferred.

    late pre-term (32-35 weeks)
    early pre-term (24-32 weeks)
    preterm, non-viable (<25 weeks)

    management of the infant


    See AAFP MOM Care and especially Laboratory-Parameters - MOM Care

    test disorder timing notes
    Initial visit package PAP, GC, chlamydia, HIV, RPR, HepB, Rh, rubella and varicella ab, type and Rh, U/A and screen. Some add PPD in high risk populations.
    CVS (chorionic villus sampling) Down's other genetic 9-12 wk Risk miscarriage, loss rate > 0.8%. (Probably higher than this 1990 value.)
    ultrasound dating 18 wk for dating, else prn Need accurate dates for screens. Earlier if dates quite poor. Note that weeks 10-17 there is increased CNS teratogenic sensitivity -- another reason to defer routine U/S to 18 weeks.
    • 6 week: sac
    • 7-14 weeks: dating by crown-rump length
    • 2nd trimester: date w/ biparietal diameter and femur length
    • 3rd trimester: date w/ biparietal diameter, abd circ and femur length

    Down syndrome associations: IUGR, nuchal fold thickness, congenital heart defect, duodenal atresia, hypoplasia of the 5th finger, two vessel umbilical cord -- but in practice this is a lousy test for finding Down's and may be discarded.

    triple screen Down's, NTD 15-20 weeks AFP, estriol, hCG. PPV is only 2%?!

    Detect 60% of Down's syndrome for age < 35y, 75% for age >= 35y. Incr hCG associated with placental problems, increased risk of low birth weight, pre-term delivery, and IUGR.

    quadruple screen Down's, NTD 15-20 wk Triple screen + inhibin A (low in Down's) increases sensitivity.
    amniocentesis Down's other genetic d/o 18 wk Risk miscarriage.
    OGC GDM 24-28 wk See gestational (GDM).
    Rh Ab screen if Rh - Hemolytic anemia of newborn 28-30 For Rh negative women preparatory to RhoGam. If positive consult!

    If negative, then give RhIg if partner is Rh positive or unknown status -- some advocate always administer. Protection lasts 12 weeks, consider renew if post-dates. Rhogam prevents devpt of Rh Ab post-partum.

    Repeat screen 26-30 U/A and screen, H/H optional
    GrpB Strep 35-37 wk CDC recommendation.
    GC / Chlam STD 36-38 wk Consider RPR and HIV as well.
    NST (nonstress test) placental insufficiency, fetal distress prn
    • do if risk factors: post-dates, DM, hypertension
    • reactive (negative): >=2 accelerations (>= 15 bpm above baseline) within 20 minutes
    • non-reactive (positive): 40 minutes without reactivity. Do CST.
    • add external stimulation if 20 min non-reactive
    CST (contraction stress test) placental insufficiency, fetal distress prn
    • nipple-stimulation version easiest, often follows non-reactive NST
    • need 3 contractions within 10 minutes
    • negative (normal) if no late decelerations
    • if positive (abnormal) then deliver (urgency depends on conditions and lung maturation), but about half the time there is no placental insufficiency
    biophysical profile placental insufficiency, fetal distress prn
    • unclear added value to NST/CST, sometimes replaces CST or used to assist in delivery timing with abnormal CST
    • includes NST, fetal movement, fetal tone, qualitative amniotic fluid volume and fetal breathing movements (FBM). All scored 0-2 (absent to normal) during observation <= 30 minutes.
      • >= 8: normal
      • 6: equivocal, repeat within 24 hours
      • < 6: deliver if lungs mature
    Herpes neonatal Herpes suspect Herpes No longer screen prior to delivery, do if suspicious lesion. C-SXN at delivery if active lesions. If primary herpes during pregnancy or if delivery through infected canal then consider treat neonate while awaiting neonatal culture.
    lecithin/sphingomyelin ratio fetal lung maturity prn
    G6PD, Hg electrophoresis, genetic screens fetal disorders prn

    Seizure Disorders in pregnancy

    1. to prevent neonatal Vit K deficiency: Vitamin K1 10 mg PQ qD from 36w onwards. (Am J Obstet Gynecol, Mar 1993)

    Author: John G. Faughnan.  The views and opinions expressed in this page are strictly those of the page author. Pages are updated on an irregular schedule; suggestions/fixes are welcome but they may take weeks to years to be incorporated. Anyone may freely link to anything on this site and print any page; no permission is needed for citing, linking,  printing, or distributing printed copies.