Pregnancy & Prenatal Care

Jennifer McDonald DO

What is the purpose of prenatal care?

WHEN SHOULD PRENATAL CARE START?

History Routine prenatal care relatively new

1900 the nurses of the instructive nursing association in Boston began

making house calls to pregnant mothers

Noticed that complications were decreased. Ultimately practice

adopted by physicians

IDEALLY, a woman planning to have a child should have a

medical evaluation before she becomes pregnant

The majority of pregnancies are unintended making pre-conceptual care challenging

25% of pregnancies worldwide will end in a termination

Why don’t women seek prenatal care?

Always TerminologyEmbryo (Greek “swelling within”)

Fertilization thru 8 weeks

Fetus (Latin “Offspring”)Beyond 8 weeks through delivery

Neonatal period = birth until 28 days of life

Terminology Premature infant < 37 weeks gestation

Post-mature infant > 42 weeks gestation Low birth weight < 2500 grams at birth

Macrosomic infant > 4500 grams at birth Spontaneous Abortion = expulsion of an

infant prior to 20 weeks of gestation Viability = 23-24 weeks gestation

Gravity & ParityGravity = Total number of pregnancies

Parity = Outcome of pregnancies Sometimes expressed as 4 digits

Full term deliveriesPreterm deliveries

Abortions (spontaneous or elective)Living children

A multiple birth is a single parous experience

Numbers Game Nulligravid = never been pregnant

Primigravid = first pregnancy Multigravid = achieved previous

pregnancies

Duration of Pregnancy

Calculated from the first day of the last menstrual period (LMP)

Average 280 days (40 weeks)

Numbers Game

Naegele’s RuleEDC = LMP - 3 months + 7 days

Example LMP 5/21 is due ??

Diagnosis of Pregnancy

Presumptive Signs

Probable Signs Positive Signs

Presumptive Secondary amenorrhea

Nausea & vomiting Breast changes

Skin changes (cholasma/linea nigra) Urinary frequency

Fatigue Quickening (first perception of fetal

movement)

Probable Signs Abdominal enlargement – uterus rises out of

the pelvis at 12 weeks Braxton Hicks contractions

Uterine souffle – rushing of maternal blood in placenta

Goodell’s sign – softening of cervix 6-8 weeks Chadwick’s sign – bluish hue to cervix after 6

weeks Fetal movement – felt 18 to 20 weeks, earlier

in multigravidas (14-16 weeks)

Positive Signs Fetal heart tones heard

Identifiable with doppler after 10 weeks Fetus identified on ultrasound

Palpation of the fetus (22 weeks) Positive hCG

Now able to be identified up to 4 days before missed period

Estimating Gestational Age Uterus palpable at pubic symphysis at

8 weeks Rises out of pelvis at 12 weeks

Mid to umbilicus at 15 weeks At umbilicus at 20 weeks

Fundal height correlates with gestational age from 26-34 weeks

Fundal Height

Measured from pubic symphysis to uterine

fundus

Should measure +/- 2 cm compared to weeks

gestation

Ultrasound Early Landmarks 5 weeks Chorionic sac; yolk sac 6 weeks Yolk sac/embryo; cardiac activity 7 weeks Embryonal movement 8 weeks Extremities visible

Measurement < 12 weeks = crown rump length

hCG LevelsGS = 1000-1200Yolk sac = 7200

Embryo/cardiac activity = 10,800

Fetal loss rate after finding cardiac activity is 5%

Ultrasound - Accuracy5 to 6 weeks +/- 4 days

7 to 11 weeks +/- 5 days

12 to 16 weeks +/- 7 days

17 to 26 weeks +/- 10 days

27-28 weeks +/- 2 weeks

29-40 weeks +/- 3 weeks

Ultrasound After 12 weeks

Head circumferenceBiparietal diameter

Femur lengthAbdominal circumference

The First Visit Present pregnancy

Establish dating Previous pregnancy history

Complications, routes of delivery, etc. Medical/Social history

Surgical history Previous gyn surgery very important

Family history

TeratogensCigarette Smoking

Only 20% of patients quit during pregnancy

Low birth weight, increased risk of fetal death, placental abruption, placenta

previa

Alcohol Exposure Alcohol crosses easily across the

placenta One of leading causes of mental

retardation Facial abnormalities

Cardiovascular defects CNS dysfunction

Fetal Alcohol Syndrome(1) CNS dysfunction low intelligence

microcephalybehavioral abnormalities

(2) Growth restriction(3) Facial anomalies

(4) Congenital heart defects

Daily ETOH not as important as max concentration at critical periods

FAS

3rd leading cause of birth defects

Significant Maternal Disorders

Seizure disorders Pre-gestational diabetes

Cardiac disease Psychiatric disorders

Thyroid disease

Initial Routine Lab Evaluation CBC

Blood type & antibody screen Rubella

Hepatitis B RPR (serologic test for syphilis)

HIV (not mandatory) Urinanalysis

Genetic Screening Advanced maternal age > 35 years old

Cystic fibrosis screening Sickle cell screening Hemoglobinopathies

TaySachs Ashkenazi Jewish (1 in 27 carriers)

Baseline risk of major congential malformations is 3.4%Baseline risk for genetic disorders is 0.5%

Prenatal Diagnosis

Chorionic villous sampling (CVS)

Amniocentesis

Frequency of Visits Monthly until 30 weeks

30-36 weeks every 2 weeks 36 weeks to delivery every

weekEvery visit:Weight/blood pressure

Urine dip: protein/glucoseFetal heart tones/fundal heightLabor symptoms/Hypertension

symptoms

Other Testing Routine screening GC/chlamydia

Pap smear Glucose challenge test

28 weeks 50 gram load/Not fasting/1 hour > 135

indicates need for 3 hour test Group B Strep (36 weeks)

Glucose Challenge Test Used for diagnosis when screening

test (1 hour) abnormal Overnight fast/100 gram load

Two or more abnormal values Fasting > 95 mg/dL 1 hour > 180 mg/dL 2 hour > 155 mg/dL 3 hour > 140 mg/dL

Rubella Infection can be communicated 7 days before

and 4 days after rash appears If develops will be 2-3 weeks after exposure

Rate of infection depends on trimester< 11 weeks = 90% chance congenital infection

11-12 weeks = 33%13-14 weeks = 24%15-16 weeks = 11%

>16 weeks = Less than 1%

Vaccinations in PregnancyContraindicated

measles mumps rubella

yellow fever

Case Dependent

polio influenza

rabies hepatitis A/B

pnuemococcal tetanus toxoid

HIV Testing ACOG recommends testing for all pregnant

women AZT in pregnancy and labor decreases

transmission from 25% to 8% Scheduled C-section (before onset of labor)

decreases transmission to 2% IV AZT 3 hours prior to c-section

Avoid amniocentesis or other invasive procedures Viral load at baseline and every 3 months

Breast feeding contraindicated

Group B Streptococcus Leading cause of life threatening perinatal

infection 15-30% women asymptomatic carriers

Early onset (80% within 6 hours of delivery) carries 6% chance neonatal mortality

GBS bacturia on initial urinanalysis implies heavy bacterial load

Routine screening perfomed 34-36 weeks Prophylaxis at delivery if positive

Quad Screen Screening for Down’s, neural tube

defects, Trisomy 18 16-20 weeks

60-70% 60% 75-80%

Trisomy 21 Trisomy 18 NTDAFP Decreased Decreased I ncreasedEstriol Decreased DecreasedhCG I ncreased DecreasedI nhibin A I ncreased I ncreased

Detection with ultrasound