Pregnancy

Preconception

  • PMHX, OBHX, FHX, Social HX

  • Screen for thyroid, DM, HTN, anemia, communicable diseases

  • Review meds and immunizations (get titers)

  • Nutrition and lifestyle

    • Importance of ↓ smoking/etOH, BMI

    • Folic acid (0.4mg) 4wks before conception and through first 3mo of pregnancy

      • Folate deficiency (during 3-4th week of pregnancy) ➔ improper closure of neural tube in embryo ➔ neural tube defect ➔ spina bifida

    • Screen for nutrient deficiencies, advise to avoid excess vitamin A

  • Educate about exposures to heavy metals/solvents

  • Screen for partner violence

DRUGS TO AVOID IN PREGNANCY

    • ABX: Tetracycline, aminoglycoside, fluoroquinolones, trimethoprim/sulfonamide, chloramphenicol, clarithromycin

      • Instead: Penicillins/cephalosporins, Macrolides, Nitrofurantoin

    • Antifungals: Ketocanazole, flucytosine, itra/fluconazole, griseofulvin

      • Instead: Topical imidazoles, nystatin, amphotericin

    • AntiHTN: ACEi/ARB, diuretics, atenolol

      • Instead: Methyldopa, dihydralazine, nifedipine, metoprolol/labetalol (only in 1st and 2nd trimester, can ➔ IUR and can cross placenta)

    • Anti-epileptics: Phenytoin, carbamazepine, valproate

    • Others: Li, isotretinoin, steroids, antacids

    • Anticoagulation

      • ONLY USE HEPARIN (low dose ASA, never high dose after 2nd trimester)

    • Analgesics

      • ONLY USE TYLENOL (NSAIDs in first trimester only)

    • Thyroid

      • PTU in 1st trimester, methimazole in 2nd and 3rd; can continue levothyroxine

Pregnancy

Physical Exam Findings

  • Telangiectasias/palmar erythema - 4wks: Vessels/red palms

  • Goodell sign - 4-5wks:- Soft cervix

  • Ladin sign - 6wks: Softening of midline of uterus

  • Hegar sign - 6-8wks: Softening of isthmus (lower) uterus

  • Chadwick sign - 8-12wks: Blue vulva and cervix

  • Chloasma - 16 wks: Facial hyperpigmentation

Fundal Height

  • 12wks: Above symphysis

  • 16wks: Between symphysis and navel

  • 20wks: Navel

  • 32wks: Between navel and xiphoid

  • 36wks: At costal arch

Human Chorionic Gonadotropin

Urine HCG can be positive 2wks after fertilization

Qualitative serum HCG can be seen 6-9d after fertilization

  • ⍺ HCG resembles FSH, LH, TSH and has limited clinical use

  • β-subunit (β-hCG):

    • Placental syncytiotrophoblasts (direct contact with maternal blood) secrete HCG

    • Doubles every 2.5days for first 4wks, peaks at 8-12wks, ↓ in third trimester

        • 5-450 in first 4wks

        • 18-1,340 in first 5wks

        • Can be 25,700 - 288,000 at peak

HCG of 1,500-2,000 (~5-6wks)

  • Gestational sac visible on US, consider ectopic if not seen

Gestational Age (Ultrasound)

  • First trimester:

    • Crown-rump length (CRL) - up to 12 wks

      • ~5cm at 12wks

  • Second and third trimesters:

    • Biparietal diameter (BPD) and head circumference (HC)

      • BPD ∼ 2.5 cm at 13wks

      • BPD ~ 9.5 cm at term

    • Fetal femoral length (FL)

      • FL ~ 1 cm at 13 weeks

      • FL ~ 8 cm at term

    • Abdominal circumference (AC)

Important Ultrasound Events

  • 4.5wks: Chorionic cavity

  • 5wks: Gestational sac (HCG level ~ 1,500–2,000)

  • 5-6wks: Yolk sac

  • 6–7wks: Fetal pole and cardiac activity

  • 10–12wks: Fetal heartbeat with doppler ultrasound

  • 18–20wks: Fetal movements

Naegele's rule (Menstrual age)

  • First day of LMP + 7d + 1yr - 3mo

Prenatal check-ups

First 28wks: Monthly

28-36wks: Every Two Weeks

36wks: Weekly

Initial visit

  • Gyn exam with PAP smear

  • CBC and Fe studies (anemia)

  • Blood typing with Rh testing (Rhesus negative mom: ppx anti-D immunoglobulins at 28wks)

  • UA/UC (need baseline protein)

  • Rubella and varicella immunity (can’t give vaccine to pregnant pt)

  • Syphilis

  • Hep C and Hep B antigen/ABs (vaccinate if no immunity)

    • Positive antigen mothers: Baby gets HepB IG and vaccine within 12hrs of birth

  • HIV testing (must be cesarean, start zidovudine and nevirapine, continue infant for 6wks)

  • Chlamydia (technically, Gonorrhea only if <25yo/high risk)

Every visit

  • Body weight

  • BP

  • UA/UC

  • Fundal height and position

  • Fetal heart and clinical assessment of fetal growth (US)

18-20wks

  • Should begin feeling first fetal movements (quickening)

24-28wks

36-41wks

  • Recto-vaginal swab for GBS

Daily calorie intake

  • First trimester: 2,200 kcal

  • Second & third trimester: 2,500 kcal

Expected weight gain

  • First trimester: ~5lbs

  • Second & third trimester: ~1-2lbs/week

Total WG

    • BMI <18.5 (low BIM) ➔ 28-40 lbs

    • BMI 18.5-24.9 ➔ 25-35 lbs

    • BMI 25-29.9 (overweight) ➔ 15-25 lbs

    • BMI >30 (obesity) ➔ 11-20 lbs

Prenatal Screening

Screening is voluntary and gives the opportunity to terminate if aneuploidy but has risks of false positives/negatives

Noninvasive screening before 20 weeks

  • Maternal serum biomarkers and ultrasound markers

First trimester combined screening at 10-13wks

  • US for nuchal translucency

  • β-HCG

  • Pregnancy associated protein A (PAPP-A)

Second trimester triple screen at 15-20wks

  • β-HCG

  • ⍺-fetoprotein (AFP)

  • Estriol

    • Add inhibin A for Quad screen

Cell-free fetal DNA (cffDNA) from 10wks on

  • Determines sex

  • High sensitivity and specificity for Trisomies

  • Used for secondary screening if abnormal screening

  • Guides invasive testing decision

Screening Results

  • US for nuchal translucency (fluid accumulation ➔ ↑)

    • ↑↑ Trisomy 21 (Down Syndrome)

    • ↑ Trisomy 18 (Edwards Syndrome)

    • ↑ Trisomy 13 (Patau Syndrome)

  • β-HCG

    • ↑ in Trisomy 21

    • ↓ in Trisomy 13, 18

    • ↑ ↑ in molar pregnancy

  • PAPP-A

    • ↓ in Trisomy 13, 18, 21 (1st trimester)

    • ↑ in preeclampsia (2nd and 3rd)

  • AFP (relies on acurate fetal gestation age)

    • ↓ in Trisomy 18, 21

    • ↑ in neural tube or ABD wall defects

  • Estriol

    • ↓ in Trisomy 18, 21

  • Inhibin A

    • ↑ in Trisomy 21

Trisomies have ↓ AFP and ↓ PAPP-A

  • Only 21 has ↑ HCG and ↑ inhibin (18 and 13 have ↓ HCG and ↓ inhibin)

Trisomy 21 (Down syndrome)

  • MC autosomal trisomy (that can survive til birth)

  • Upward palpebral fissures with epicanthal folds and strabismus, small oral cavity and narrow palate

    • Low set ears, broad, flat nose

  • ↓ AFP and ↓ PAPP-A

  • ↑ HCG and ↑ inhibin A

  • ASD, duodenal atresia, hypogonadism, hypothyroid, DMT1

Trisomy 18 (Edwards syndrome)

  • 2nd MC autosomal trisomy (that can survive til birth)

  • Contracted fists with overlapping fingers, cleft lip/palate, micrognathia (mandibular hypoplasia)

    • Also has low-set ears

  • ↓ AFP and ↓ PAPP-A

  • ↓ HCG, normal/↓ inhibin A

  • ~50% die in first 2wks and only ~10% survive first year; can move into school years with severe ID and GI/cardiac problems

Alternative option of invasive genetic testing before 20 weeks

Chorionic villus sampling at 10-13wks

  • Transcervical/transABD chorionic tissue removal with US guidance to analyze DNA

    • ↑ risk of miscarriage and limb defects

Amniocentesis from 15wks on

  • TransABD puncture with US guidance to analyze amniotic fluid

    • ↑ risk of miscarriage, PROM, infection

Cordocentesis from 18wks on

  • TransABD puncture of umbilical cord with US guidance to analyze amniotic fluid

    • ↑ risk of miscarriage, infection