Pregnancy Part 1 – SOGC 2014/ TN2014

Definitions:
  • First Trimester = 0-12 wks          Second = 12-28 wks       Third = 28-40wks
  • Term = 37-42
  • Active Labour: regular contractions result in cervical change / descent of the fetus (presenting part)
  • Gravity = # pregnancies of any gestation
  • T = # of term infants P = # premature A = # of abortions L = # of living Children

1 In a patient who is considering pregnancy:
a) Identify risk factors for complications.
b) Recommend appropriate changes (e.g., folic acid intake, smoking cessation, medication changes).

Preconception Counselling

  • GA 3-8 wk is a critical period of organogenesis
  • PMH – optimize medical illness
Supplements
  • Folic acid supplement 8-12 wk preconception until end of T1
    • 0.4-1mg/d
    • 5mg/d if previous NTD, anti-epileptic meds, DM or BMI >35
  • Iron supplement & prenatal vitamins
Risk Modification:
  • Lifestyle: balanced nutrition & physical fitness
  • Meds – ? teratogenic
  • Infection screening: rubella, HBsAg, VDRL, Pap smear, G/C, HIV
  • Genetic testing – appropriate for high risk group
  • Social: EtOH, smoking, drug use, domestic violence (ask every women about abuse)

Counselling:

Nutrition
  • Ca 1200-1500mg/d + Vit D 1000 u – 3-4 servings of milk daily
  • Daily caloric increase – 100 cal/d in 1st, 300 cal/d in 2nd, 450 cal/d in 3rd
    • Wt gain 6.8-18.2 kg (depends on pre-pregnancy weight)
  • Advise all women of childbearing age to supplement diet with 0.4mg/day (5mg/d if high risk) Folic acid for the first 12 wk of(materna has 1 mg/day)
    • decreases indicence of NTD
    • Food rich in folic acid: spinach, lentils, chick peas, asparagus, brocoli, peas, brussels sprouts, corn and oranges
  • Iron supplement (0.8mg/d in T1, 4-5mg/d in T2, >6mg/d in T3) if anemic, prenatal vitamins
    • Req amount > normal body stores & typical intake – need supplement iron
    • daily multivitamin not necessary in 2nd trimester (unless not consuming an adequate diet)
  • Essential fatty acids – vegetable oils, margarines, peanuts, fatty fish
    • supports fetal neural and visual development
Caffeine – diuretic & stimulant
  • 1-2 cups/d are safe during pregnancy (SOGC)
  • <200mg/d is not thought to contribute to miscarriage or preterm birth / relationship to IUGR ? (AOGC)
Food Borne illnesses
  • Avoidance of cats/litter/rodents (toxoplasmosis), soft cheeses/deli meats, smoked salmon, pates (listeria), raw fish / eggs / poultry, unpasteurized dairy products
  • 0.5ppm of mercury in fish is not considered harmful – limit consumption of top predator fish, eg shark, swordfish, tuna (one meal / month)
Social Hx:
  • EtOH – no amount is safe in pregnancy
    • encourage abstinence
    • ↑ SA, stillbirth, congenital anomalies (FAS)
  • smoking – reduce or quit
    • ↑ low birth wt, placenta previa / abruption, SA, preterm labour, stillbirth
  • Drug cessation
    • Cocaine ↑ microcephaly, growth retardation, prematurity, placenta abruption
  • Inquire about safety, domestic violence, genetic disease
  • Exercise
    • C/I: ROM, Preterm labour, HTN, Incompetent Cervic, IUGR, multiple gestations (>3), placenta previa >28wk GA, 2nd/3rd trimester bleeding, twin pregnancy >28wk GA
    • uncontrolled DM1 / thyroid dz, anemia (hgb <100) other CVS / Resp / endo disorders
  • Work – strenuous work / extended hours and shift work – ↑ low birth weight, prematurity, SA
  • Travel – not harmful, air travel ok in T2, cutoff GA36-38wk (depending on the airline)
  • Intercourse – continue except
    • at risk for abortion, preterm labour, placenta previa
    • breast stimulation may induce uterine activity
PmHX
  • heart conditions, past uterine/cervical procedures, STI’s
  • maternal age, birth defects, multiple gestation
Med: 
  • Review meds/OTC meds. – motherrisk.org
  • Discuss cessation of current form of birth control
Family Hx:
  • Genetic screening of high risk groups (tay-sachs, sickle cell, thalessemia)

2 In a female or male patient who is sexually active, who is considering sexual activity, or who has the potential to conceive or engender a pregnancy, use available encounters to educate about fertility.

Discuss STI’s, appropriate forms of contraception, and emergency contraception.

Dx of pregnancy

Symptoms:

  • amenorrhea – LMP, N/V, breast tenderness, u frequency, fatigue
  • Nagele’s rule = 1st day of LMP + 7days – 3 months.

Signs:

  • Goodell’s sign – softening of the cervix (4-6wk)
  • Chadwick’s sign – bluish discolouration of the cervix / vagina (6wk)
  • Hegar’s sign – softening of the cervical isthmus (6-8wk)
  • Uterine enlargment / breast engorgement

3 In a patient with suspected or confirmed pregnancy, establish the desirability of the pregnancy.

Confirm pregnancy with urine/serum bHCG &/or US

  1. Serum bHCG – positive 9 d post-conception
    • doubles Q1-2 d, peak 8-10wk, fall to a plateau until delivery
    • Less than expected
      • ectopic, abortion, inaccurate dates
    • Higher than expected
      • Multiple gestation, molar pregnancy, T21, inaccurate dates
  2. Urine bHCG – positive 28d after LMP
  3. US
    • Transvaginal
      • 5wk – gestational sac (bHCG >1500), 6 wk – fetal pole, 7-8 wk – fetal heart tones
    • Transabdominal 
      • 6-8wk – intrauterine pregnancy visible (bHCG – >6500)

4 In a patient presenting with a confirmed pregnancy for the first encounter:
a) Assess maternal risk factors (medical and social). – objective 1
b) Establish accurate dates.
c) Advise the patient about ongoing care.

Repeat visits q4weeks until 28, q2weeks until 36, qweekly until delivery.

>2-3mo preconception
  • See Objective 1
  • Folic acid 0.4-1mg od + Iron
  • Risk factors: Folic acid 5mg od
    1. Hx of baby with NTD, facial cleft, heart/urinary/limb defect
    2. Family hx of NTD, DM
    3. Smoking, obesity, poor diet, substance abuse, forgets to take vitamins daily
    4. Epileptics on valproic acid or carbamazepine
<12 wk Routine Dating U/S for all pregnant women (SOGC 2014):

  • First-trimester crown-rump length is the best parameter for determining gestational age
  • the earliest ultrasound with a crown-rump length equivalent to at least 7 weeks (or 10 mm) should be used to determine the gestational age
  • Between the 12th and 14th weeks, crown-rump length and biparietal diameter are similar in accuracy. It is recommended
    that crown-rump length be used up to 84 mm, and the biparietal diameter be used for measurements > 84 mm
  • U/S more accurate than LMP dates if ≤ 23 weeks GA
  • If a T2/3 scan is used to determine gestational age, a combination of multiple biometric parameters
    (biparietal diameter, head circumference, abdominal circumference, and femur length) should be used to determine
    gestational age, rather than a single parameter. (II-1A)
  • When the assignment of gestational age is based on a T3  ultrasound, it is difficult to confirm an accurate due date.
    Follow-up of interval growth is suggested 2 to 3 weeks following the ultrasound.
  • u/s dating reduces inductions for post-term pregnancies

U/S also for

  1. Threatened abortion, incomplete abortion, prior to termination
  2. Suspected multiple gestation, ectopic pregnancy, molar pregnancy, and suspected pelvic masses
  3. Increased risk for major fetal congenital malformations
≥12 wk routine FHR with handheld Doppler
>8 wk
  1. Routine prenatal b/w: ABO group, Rh & Ab, CBC, HIV, rubella, syphilis, hep B sAg, Hep C ab, U/A, U Cx, urine for G/C, TSH (optional but routine in most places)
  2. VZV ab (if no hx of varicella),
  3. A1c for high risk of DM
    • Aboriginal, hispanic, South Asian, Asian, African
    • Prev Hx of GDM or glucose intolerance, macrosomia (>4000g), unexplained stillbirth, neonatal hypoglycemia, hypocalcemia, or hyperbilirubinemia
    • Advanced maternal age >35yo, obesity, repeated glucosuria in pregnancy, polyhydramnios, suspected macrosomia, PCOS, acanthosis nigricans, corticosteroid use

Visit 1: Fill out prenatal forms, refer if needed

  • Inquire about financial concerns, living situation, paternity, abuse, stresses/supports (don’t forget to FIFE the patient).

Visit 2: Physical Exam + Pap Smear, if not done in past 6mo & >21yo, vaginal swab for BV, cervical Cx for G/C

UTI UTI and asymptomaic bacteriuria (midstream Cx >105 )Tx: Macrobid 100mg po bid x 7 days – avoid at labour and delivery due to hemolytic anemia

  • TMP-SMX 1DS tab bid x 3 days (avoid 3rd trimester & near term)
  • TMP 100mg bid x 7 days (avoid in 1st trimester)
  • Amoxicillin 500mg tid x 7 days
  • Clavulin 500mg bid x 7 days
  • Keflex 250mg qid x 7 days

Repeat U Cx in 1-2 wk after Tx

11-13wk + 6d CVS prn, 1% risk of loss, earlier dx than aminocentesis1st trimester integrated serum screen – Part 1 – T18, 21 & U/S NTSIPS vs. IPS (SIPS + NT): Depending on the age(risk) of your patients and their desire for screening after informed consent. Amniocentisis may be offered after age 40 with no prior screening (http://www.bcprenatalscreening.ca/page202.htm)Indications for Nuchal Translucency U/S:

  • Multiple gestation,
  • age>40yo at EDD, Age>35 with >=3 SA
  • Personal / family Hx of T18, 13, 21
16 wk TA cut-off in most provinces
15-17wk Amniocentesis – routinely offered to women >40yo & >35yo with multiple gestation; 0.5% risk of loss
15-20wk + 6d(16-18wk) Part 2   or Quad screen (if no part 1) – T18, 21, ONTDs
18-24wk Routine u/s for dates (inaccurate +/-2wk) /anomalies
≥20wk SFH measurement routinely
24-26 wk
  1. GDM screen: 1hr 50g nonfasting GCT
    • <7.8 normal, 7.8-10.2 – 75g OGTT, >10.3 – GDM
  2. 75g OGTT: to confirm if positive with 1hr test
    • DM if >5.3/10.6/8.9 at 0,1,2hr
28wk Repeat CBC / Hg (screen with anemia in T3) often with GDM screening (24-26wk)Re-screen STI/HIV if high risk

  • Rh – : repeat type & screen for alloantibodies before Adm
  • Rh +: repeat type & screen for alloantibodies – not necessary if 2 previous results on file
  • RH – : Rhrogam 300mcg IM
30-32wk u/s to r/o IUGR in women w/initial wt >90kg or BMI >30
28-36 wk Repeat HIV, G/C, syphilis testing if at risk
35-37 wk GBS swab (36wk) – vaginal + rectal (valid for 5 wk), send result to delivery suit unless + GBS bacteriuria during the current pregnancy or prev infant with GBS dz
38+ wk Consider Cervical exam at prenatal visitOffer sweeping of membranes to prevent posterm getation
41-42 wk Induction to prevent posterm gestation vs expectant (req fetal monitoring with NST & AFT bi-weekly
Delivery
  • Rh – : Rhrogam 300mcg IM within 72hr of delivery if Rh+ baby
  • Rubella immunization to nonimmune women
  • BCG for baby, routinely offered to high-risk population, mother be HIV –
  • Intrapartum Prophylaxis:
    • Prev infant with invasive GBS dz
    • + GBS screen in current pregnancy
    • Unknown GBS + <37wkGA or ROM>18hr or intrapartum temp >38oC – use broad-spectrum abx if amnionitis
    • Pen G 5million u IV then 2.5 million u IV Q4h
      • Cefazolin 3g IV then 1g IV q8h (if pen allergy)
      • Clindamycin 900mg IV q8h until delivery (pen anaphylaxis risk)
      • Erythromycin 500mg IV q6h
      • If GBS resistant or susceptibility unknown:
        • Vancomycin 1g IV q12h
    • Prophylaxis not reg:
      • Planned C/S in absence of ROM or labour
      • -ve GBS Cx in current pregnancy (despite prev pregnancy with + GBS) – regardless of intrapartum risk factors
Postpartum GDM – a 75g OGTT at 6-12 wk pp to screen for persistent DM or impaired glucose tolerance

5 In pregnant patients:

a) Identify those at high risk (e.g., teens, domestic violence victims, single parents, drug abusers, impoverished women).
b) Refer these high-risk patients to appropriate resources throughout the antepartum and postpartum periods.

OB consult if
  1. posible C/S: VBAC, malpresentation, multiple gestation
  2. antepartum care: HTN, PTL/PPROM, failure to progress/descend, induction / augmentation if high risk
  3. PP care: 3/4 degree tear, retained placenta
Refer to social worker and local mental health unit

 


6 In at-risk pregnant patients (e.g., women with human immunodeficiency virus infection, intravenous drug users, and diabetic or epileptic women), modify antenatal care appropriately.

Diabetes:
  • Insulin for type 1, or type II uncontrolled by diet alone. Oral hypoglycemics (especially glyburide) are controversial
  • Diet usually adequate for GDM. Multi-disciplinary approach with diabetes educators, dieticians, and maternity care provider.
HIV:
  • Fetus at risk of IUGR, pre-term labor or PROM.
  • Rescreen for HIV at 28 – 36 wk GA if high risk
  • May deliver vaginally. Combined retroviral for antepartum decrease risk of transmission to <1%.
  • Discuss risk of transmission with breast feeding.
Epileptics:
  • For planning a pregnancy, switch to the safest effective anti-convulsant at lowest dose(avoid valproic acid). If already pregnant, continue with same anti-convulsant meds.
  • Folate supplementation 5mg/d.
  • Vit K supplementation in final month with enzyme inducing meds.
  • Monitor drug levels.
IVDU:
  • Arrange supports, encourage cessation,
  • surveilance for HIV/Hep B/C during pregnancy – repeat screening in T3

 

References:

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Posted in 76 Pregnancy, 99 Priority Topics, FM 99 priority topics, OB

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