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

Gestational diabetes screening
28wks and RhD negative
- Give anti-D immune globulin (RhoGAM)
- Repeat RBC antibody screening

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

Google Sites

Report abuse