OB/GYN Review

Starting at 5 weeks

embryo

Fetus

Infant

A fetus delivered between 24 - 37 weeks

From 37-42 weeks

The number of pregnancies that led to a birth beyond 20 weeks gestation OR an infant weighing more than 500 g.

Determines the estimated date of delivery (EDD or EDC):

Starting with the LMP, add 1 year, substract 3 months, then add 7 days.

-C.O. increases by 30-50%
-Systemic vascular resistance decreases due to elevated levels of progesterone that causes smooth muscle contraction

-Tidal volume increases by 30-40%, but TLC decreases by 5% due to elevation of the diaphragm

By 14-16 weeks gestation

-Relaxation of the lower esophageal sphincter
-Prolonged gastric emptying

Ureters dilate during pregnancy and the kidneys increase in size

b/c the GFR increases by 50% early in pregnancy and is maintained until delivery

-Plasma volume increases by 50%
-RBC volume increases 20-30%
-Decreased Hct

Using doppler US, FHT's are first heard at 10-12 weeks gestation

Using a fetoscope auscultation, FHT's are first heard at 18-20 weeks

Maternal sensation of fetal movement.

Usually occurs at 18-20 wks GA in first time pregnant mothers, and 16-20 weeks in mutiparida women

1. Femur length
2. Head circumference
3. Biparietal diameter
4. Abdominal circumference

2nd

1st

3rd

Painless, low-intensity contractions usually palpated starting at 14 weeks GA (2nd trimester)

The actually cause urine retention

They decrease sphincter tone in the proximal urethra, causing leakage of urine and URGE incontinence.

They increase sphincter tone in the proximal urethra, causing urinary retention and OVERFLOW UI.

They can reduce smooth muscle contractility in the bladder and occasionally cause urinary retention and OVERFLOW UI.

Urge or overflow UI

-Urge incontinence (50% to 75% prevalence)

- Detrusor contracts when it should be relaxed

Overflow incontinence

Urge incontinence

Stress incontinence

Stress

Urge

Overflow

ADL's reflect a patient's ability to perform basic self-care.

IADL's reflect a patient's ability to perform tasks that are required to maintain an independent household.

These are changes UNRELATED to the uterus or fetus.

N/V, skin changes, breast tenderness, ammenorrhea, Chadwick's sign

Presumptive signs of pregnancy that include bluish discoloration of the vulva, vagnia, and cervix

Probable signs:

These include uterine enlargement, + B-hCG test, uterine contractions, palpation of fetal parts, Hegar's sign

A propable sign of pregnancy:
softening btwn the fundus and cervix

Definitive signs:

Ultrasound imaging is the most specific!, also auscultation of fetal heart tones, x-ray imaging of the fetus, fetal movements by the examiner

-Diabetes mellitus
-HTN
-Seizure disorder
-Previous perinatal death, fetal anomaly, preterm delivery
-Inherited dz's, retardation, birth defect, perinatal deaths
-EtOH, tobacco, drug use, poor nutrition, eating disorders

-CBC, UA, sickle cell, TB
-Serology (VDRL or rapid plasma reagin, HIV
-Oral glucose tolerance test
-Atypical Ab's
-Blood type, Hepatitis B surface Ag, Rubella Ab's
-Triple marker screen
-Sonogram

Every 4 weeks

Every 2 weeks

Every 1 week!

15-20 lbs

30-40 lbs

25-30 lbs

-Give iron 30 mg daily
-Give folate supplementation 0.4 mg daily

20 weeks GA

12 weeks GA

16 wks GA

Polyhydramnios

Oligohydramnios (inadequate amniotic fluid)

Intrauterine growth restriction is dx when sonographic fetal growth falls BELOW the 10th %ile expected for gestational age.

Symmetric: Fetal in origin due to decreased growth potential

Asymmetric: Placental etiology due to inadequate nutritional substrate availability

The degree of extenstion of the presenting part through the birth canal.

-above the level of the ischial spines, represented as a negative #

-Below the level of the ischial spines, represented as a positive #

The degree of extension or flextion of the fetal head

-Most common attitude is VERTEX = fetal head flexed w/ chin against chest

The relationship btwn a reference point on the fetal presenting part and the maternal bony pelvis.

-Most common position is OCCIPUT ANTERIOR

Engagement
Descent
Flexion
Internal Rotation
Extension
External Rotation
Expulsion

Stage 1: Latent --> Active
Stage 2: Descent
Stage 3: Expulsion

Effacement - Latent phase

Dilation (active phase of labor, rapid cervical dilation)

Remember the 15/15 2/20 rule:
There must be an increase in fetal heartbeat of 15 beats or greater that lasts for at least 15 seconds.

There must be 2 accelerations of the fetal heart rate in a 20 minute period

The NST is a test of the fetal heart rate.

1. Non-stress test (NST)
2. Contraction stress test (CST) or Oxytocin challenge test
3. Biophysical profile (BPP)

- Hx of STD or PID
-Prior ectopic preg
-Previous tubal surgery
-Endometriosis
-Use of IUD for birth control
-Current use of estrogen or progesterone

beta-hCG level that is LOW for gestational age and doesn't increase at the expected rate

Ectopic pregnancy

1,500 mlU/ml

> 5,000 mlU/ml

Methotrxate

Ectopic pregnancy

-About 1% of all pregancies are ectopic

Ectopic pregnancy

spontaneous abortion; occur in 15-25% of all pregnancies

Threatened abortion

Abortus

-SAB
-Post-coital bleeding
-Ectopic pregnancy
-Vaginal or cervical lesions/lacerataions
-Extrusion of molar pregnancy

D&C: Dilation and cutterage

Misoprostol that causes cervical dilation and uterine contractions

Chromosomal abnormality

D&C - for abortions that occur prior to 20 weeks GA

D&E - for aborions that occur after 20 weeks GA (2nd trimester abortions, etc.)

Secondary to cervical or uterine abnormalities, trauma, systemic disease, infection

Incompetent cervix

Accounts for 15% of 2nd trimester losses

-Hx of cervical lacerations w/ vaginal delivery
-Hx of DES exposure
-Uterine anomalies
-Hx of cervical surgery (cone biopsy, dilation of the cervix)

Antiphospholipid antibody syndrome

Anytime after 15 weeks GA.

It is used to obtain the fetal karyotype once the chorion and amnion have fused.

Can be performed earlier than an amniocentesis! Usually between 9-11 weeks GA.

CVS

PUBS= periumbilical blood sampling

This can also be used to obtain a more rapid fetal chomosome analysis

PPROM= preterm; a rupture of membranes that occurs before 37 weeks GA

PROM= rupture of membranes that occurs after 37 weeks GA

-Speculum exam to asses for fluid collection in the vaginal vault of fluid leaking from the cervix

-Nitrazine test: test fluid w/a strip of acid-base paper --> amniotic fluids are alkaline, so paper should turn blue (compared to vaginal secretions that are acidic and turn red)

-Fern test: Place drop of fluid onto slide to look for pattern that resembles a fern leaf. Estrogens from amniotic fluid cause crystallization of salts also found in amnio fluid causing fern pattern.

8 or greater

1. Cervical dilation (cm)
2. Effacement (%)
3. Station
4. Cervical consistency
5. Cervical position

-Prostaglandins (such as PGE2 gel, cervidil, or misoprostol)
-Oxytocin
-AROM
-Mechanical dilation of the cervix

If the mom has asthma or glaucoma

110-160 bmp

-Infection
-Hypoxia
-Anemia

12%

3%

<1% - This is the best pregnancy rate among the methods of contraception!

8%

Early menopause, glucocorticoid therapy, sedentary lifestyle, alcohol consumption, hyperthyroidism, hyperparathyroidism, anticonvulsant therapy, vitamin D deficiency, family history of early or severe osteoporosis, or chronic liver or renal disease.

Starting at age 65

1. MMR
2. Varicella

No! The rate does not change, but the tidal volume increases which also causes an increase in minute ventilation.

The majority of estrogen is produced by the placenta! The ovaries also contribute to insulin production but to a lesser extent.

hCG

Peaks at 10-12 weeks GA

Steady state after 15 weeks GA

Alpha subunit: is identical to the alpha subunits of LH, FSH, and thyroid stimulating hormone (TSH)

hPL is also known as human chorionic somatomammotropin.

hPL ensures a constant nutrient and energy supply to the fetus during pregnancy.

Causes lipolysis to increase circulating free fatty acids

It decreases maternal insulin sensitivity leading to increased insulin resistance and a diabetic state.

Neural tube defects, hydrocephalus and craniofacial malformations.

Often performed at 10-12 weeks

The sampled placental tissue may be analyzed for fetal chromosomal abnormalities, such as Trisomy 21, biochemical, or DNA-based studies.

It CANNOT be used to asses for neural tube defects!

Inhibin A: a more sensitive screening test for Down syndrome

The three components are
1. Maternal serum AFP
2. hCG
3. Unconjugated estriol (the estrogen of pregnancy)

Used to screen for Down syndrome, trisomy 18 and neural tube defects.

1. Maternal AFP
2. beta-hCG
3. Estriol
4. Inhibin A (more specific marker for Down's Syndrome)

Performed at 15-18 weeks GA

AFP and estiol levels are DECREASED

bHCG and Inhibin A are INCREASED

At 15-18 weeks GA, but before 20 weeks GA to allow for elective termination of the pregnancy if desired

Quad screen

Approximately 1.2 %

Fragile X syndrome

Down's Syndrome - due to a chromosomal anomaly

1. Nuchal translucency
2. Serum PAPP-A
3. Free beta-hCG

Shoulder dystocia, metabolic disturbances, preeclampsia, polyhydramnios and fetal macrosomia

4mg

15-20 lbs total

The first 8 menstrual weeks

Up to 25 %

> 300 mg/24-hr

>5000 mg/24-hr (5 grams)

Previous history of the disease, chronic HTN, multifetal pregnancy and molar pregnancy

No!!!!

Pulmonary edema at levels > 12mEq/L
Cardiac toxicity at levels > 15 mEq/L

NOTE: The therapeutic range for magnesium is 4-7 mEq/L

Pyelonephritis

Ultrasound measurement of crown rump length

Tear of the vaginal mucosa

Tear of the vaginal fascia and the perimeum

partial or complete transection of the rectal sphincter

Tear through the external and internal anal sphincter, along with the rectal mucosa

> 12 cm

Fetal heart rate < 110 beats per minute

-severe vaginal bleeding
-advanced labor
-mature fetus
-intrauterine infection
-severely anomalous fetus

The non-stress test (NST)

Two fetal heart rate accelerations that rise at least 15 bpm over baseline that each last for a duration of 15 seconds that occur within 20 minutes of each other.

Prolonged periods of fetal tachycardia (HR > 160 bpm)

Caused by fetal head compression during uterine contraction, resulting in vagal stimulation and slowing of the heart rate.

This type of deceleration starts and ends with uterine contraction.

late decelerations

Umbilical cord compression

A symmetric fall in the fetal heart rate, beginning AT or AFTER the peak of the uterine contraction and returning to baseline only after the contraction has ended.

Associated with uteroplacental insufficiency.

4.5 - 5.5

7.0 - 7.5

1. Nitrazine pH test of vaginal fluid - if membranes have ruptured, the pH will be alkaline (> 6.5); but must watch out for false + from blood which is also alkaline

2. Ferning: a fern-like pattern that can be seen on microscopic exam when estrogen and amniotic fluid mix together and cause salt crystallization

overflow incontinence

Prolactin

oxytocin

streptococci

increases by 40-60% btwn 12 and 36 wks GA

increases 15% without iron supplementation; increases 30% with iron supplementation

decreases

increases greatly

increases due to increased number of neutrophils

Approaches approx 16,000

decreases by 35% by term

= iron storage capacity

Increases by 100% by 2nd trimester

TIBC increases by 25-100%

= storage form of iron

decreases

human placental lactogen

increases

increases from 70-85 bpm

increases

DECREASES

UNCHANGED

measuring crown rump length at 5-12 weeks GA

1000
10,000
100,000
15,000-25,000

3rd degree

500 mL

1000 mL

3 or less

None! Place the baby on the warmer.

Hemipareisis - it often involves the middle cerebral artery

placenta previa - must do a c-section!
Abruption
Vasa previa - must do c-section!
Labor with bloody show
Low lying placenta
Trauma
Sexual intercourse - semen contains prostaglandins that can lead to uterine contractions and thinning of the cervix

placenta percreta

plaenta increta

placenta accreta - the most common form of abnormal placentation

formation of intrauterine adhesions which typically result from scars that develop after uterine surgery.

overdistended uterus (twins, macrosomnia, polyhydraminos)

prolonged labor

chorioamnionitis

precipitous labor

fetal head compression

Compression of the umbilical cord - often due to a change in maternal position

acute placental insufficiency

At 28 weeks GA and postpartum

90% of cases are due to a prior uterine scar, such as from a C-section or other uterine surgery

Presentation: sudden onset of intense abdominal pain

Placental abruption (abruptio placentae)

50% of cases occur before labor and after 30 weeks GA

Advanced maternal age
Multparity
Pregnant with multiples
Diabetes Mellitus
Trauma
Motor Vehicle Accident

You should not perform a vaginal exam because it can lead to more bleeding. Instead, you should dx with an ultrasound

Placenta previa

Placenta accreta

Placenta increta

Placenta percreta

About 60%

Compression of the fetal head (this is vagally mediated)

Compression of the umbilical cord (this is vagally mediated)

Uteroplacental insufficiency

1. Non-stress test
2. Amniotic fluid index
3. Fetal breathing movements
4. Gross body movements
5. Extremity tone

Each of the 5 parameters is assigned a score of 0-2. Max score is 10, lowest score is 0.

Score 8-10 = REASSURING, follow up w/ repeat BPP

Score 4-6 = Equivocal, f/u with delivery of the fetus if gestation >36 weeks; or repeat BPP

Score 0-4 = Delivery baby immediately!

This means there were NO late decelerations seen in the presence of 3 uterine contractions that occurred within 10 minutes. This is REASSURING! Follow up with a repeat CST weekly.

This means there are repetitive late decelerations seen with 3 consecutive uterine contractions within 10 minutes. This is WORRISOME! Deliver the baby now!

This is consistent with a fetal neural tube defect.

Increased amniotic fluid acetylcholinesterase level confirms an OPEN neural tube defect.

Non-stress test (NST)

Perform a NST

3 in 1,000

Perform vibroacoustic stimulation

7.20 or greater

pH <7.20 indicates fetal acidosis, so deliver the fetus immediately

1. Placenta previa
2. Abruptio placentae
3. Abruptio placentae