Maternal Physiology / Normal Pregnancy and Prenatal Care / Imaging in Obstetrics Flashcards
Maternal Physiology
Pregnancy changes anatomy, physiology and biochemistry
Affects normal lab values
Affects medication dosing
Cardiovascular System 1 ?
As uterus enlarges, heart rotates
Apical impulse shifts laterally
Heart size increases by 12%
Blood plasma volume increases ~50% - Varies by Size of woman Number of prior pregnancies Number of fetuses
Cardiovascular System 2 ?
Cardiac output increases 40%
Stroke volume increases 25-30%
-Sensitive to maternal position
-Lateral recumbent
-Supine -they are compressing the vena cava
so lay on right or left side
Cardiovascular System 3 ?
Systemic arterial pressure decreases initially (until 24-28 weeks)
Venous pressure increases in legs
-Pressure on inferior vena cava and common iliac veins
-Edema
-Varicosities
feet swelling is normal but arms not so much
Cardiovascular System 4 ?
Blood flow distribution
Increased flow to uterus, kidneys, breast and skin - helps dissipate the heat
Strenuous exercise
- Diverts blood flow to large muscles
- Okay for conditioned mothers
- For nonconditioned, can decrease uteroplacental perfusion to the fetus
Cardiovascular System 5 ?
90% of gravidas have systolic ejection murmurs
Increased CO
Decreased blood viscosity
Pulmonary System 1 ?
Engorgement of nasopharynx, larynx, trachea and bronchi
Increased vascular markings on CXR
Diaphragm elevates 4 cm - SOB
- Reduced total lung capacity
- ribs flare out a bit more ( look below too)
Increased thoracic circumference
Decreased total lung capacity
Increased tidal volume
-Decreased reserve and residual volume
Renal System 1 ?
Kidney lengths enlarge by 1-1.5 cms
Ureters elongate and widen - curve around uterus
Collecting system can contain 200 mL
- Increased risk of UTI’s
- hold more volume but increase risk of UTI
Back to normal 4 days postpartum
Renal System 2 ?
Blood flow to kidneys increases by 50-85% during first half of pregnancy, lower later
Urinary flow increases two-fold in LATE pregnancy when in lateral recumbent position ( compared to supine)
Medications cleared by the kidney faster
Half of pregnant women will have glucosuria sometime during pregnancy
-NL also contributes to UTI rate
Renal System 3 ?
Early in pregnancy, hormones contribute to increased urinary frequency
Bladder capacity actually enlarges
Later in pregnancy, frequency due to enlarged uterus (pressure)
Gastrointestinal System ?
Stomach pushed upward
Bowel pushed back, to sides and up
Increased salivation (due to nausea?)
Gums may hypertrophy, bleed
-hormones , or even OCP
Increased GERD, esp first trimester
-more gastrin being produced and esophageal peristalsis being decreased
Increased constipation in later months
-cause slower transit time of stool
Increased risk of gallstone formation
-cause of bile stasis , GB disease
Hematologic System 1 ?
Red cell mass expands by 33%, even more with iron supplementation
Greater plasma increase – anemia of pregnancy cause of dilution factor
Active transport of iron to fetus
Fetus generally not anemic, even if mother is severely anemic
Hematologic System 2 ?
WBC’s 5000-12,000 in third trimester
not infection
20,000-25,000 during labor is normal
Mainly polymorphonuclear cells
- Basophils decrease slightly
- Eosinophils unchanged
Platelet production increases, but so does consumption = thrombocytopenia
-Resolves with delivery
Skin: Hyperpigmentation ?
Linea nigra
Chloasma - “mask of pregnancy”
Skin: Striae gravidarum ?
“stretch marks”
Abdomen, breasts, thighs, buttocks
Decreased collagen adhesiveness and it just pulls apart
Genetic predisposition
No effective treatment
Skin continued ?
Spider angiomas
Palmar erythema- cause more heat through the hands trying to be released
Cutis marmorata - vasomotor instability
Hemorrhoids
Brittle nails with grooves (Beau’s lines)
-trauma to the body and the blood etc go else were causing this
Thickened hair (ends 1-5 months postpartum and shedding begins
Metabolism: Increased nutritional requirements ?
Rest more
Increased appetite (for some)
Pica (rare) - dirt
Metabolism: Weight gain ?
Uterus and contents ( fetus)
Breast enlargement
Blood and water volume 6.8L
Average weight gain is 27.5 lbs
Placenta ?
Purpose is physiologic exchange between fetal organs and maternal tissue
Oxygen and nutrients to fetus
CO2, urea, catabolites back to the mother
Placenta: Cotyledons ?
Cotyledons – 12-15 subunits of the placenta - tents of blood where the blood collects and during contraction they collapse
At height of contraction, cotyledons are mainly devoid of blood flow. In uterine tetany, fetal hypoxia develops
Placenta and Placental-Fetal Unit: Produces increasing amounts of steroids in late ?
first trimester
Placenta and Placental-Fetal Unit: Fetal adrenal cortex _______ than adult
larger
helps with fetal development and growth , maturation and delivery
Placental Secretions ?
Human chorionic gonadotropin- hCG
Properties similar to LH from pituitary
Alpha subunit common to all glycoproteins
Beta subunit is specific to the hormone
HcG secretions: Measurement of β-hCG detects pregnancy______ after fertilization ( qualitative)
6-12 days
HcG secretions: Levels peak at ______ gestation
60-90 days
then we look for quantitative and if it is still increasing and increasing then it could be ectopic
Placental Transport of Drugs: Few substances that won’t cross the “placental barrier” ?
Heparin
Insulin
these wont cross cause Too large of molecules
Umbilical Cord: Connective tissue of cord is called ?
Wharton’s jelly
Umbilical Cord: ___arteries, ___ vein twisted around each other
Two
one
Umbilical Cord: _______ carry blood from fetus to the mother
Arteries
Umbilical Cord: ____ returns blood to the fetus
Vein
Umbilical Cord: Average diameter ?
12 mm
Umbilical Cord: Average length ?
50-60 cms
Umbilical Cord: Nuchal loops around baby’s neck 25% of _________________ deliveries
spontaneous vertex
Umbilical Cord: Short cord related to _______________ maybe a shorter umbilical cord
oligohydramnios
not enough amniotic fluid
Umbilical Cord: True knots in __ of deliveries – can lead to fetal demise
1%
Umbilical Cord: At delivery, a portion of the cord should be kept for ?
cord blood gas sampling
more accurate then a APGAR score and it is preserved for several hours
Normal Pregnancy and Prenatal Care definition ?
Pregnancy defined as the physiologic process of a developing fetus within the maternal body
Gestational age is the amount of time since first day of ____
LNMP
(precedes fertilization by 2 weeks)
Assume a 28 day cycle
Gestational age expressed in ?
Expressed in completed weeks
__ weeks to term pregnancy
40
_________________ age is the age of the conception, calculated from time of implantation
Developmental/fetal
Naegele’s Rule calculates ?
estimated due date (EDD)
Naegele’s Rule ?
Add 7 days to first day of LNMP
Subtract 3 months
Add 1 year
Ex: First day of LNMP 5/1/15
Gestation: Divided into __ trimesters, each __ calendar months
3
3
Gestation: First trimester has two parts ?
Embryonic period
Fetal period
Embryonic period: ____weeks gestational age
2-10
Embryonic period: Most sensitive to ?
teratogens
- *sometimes people dont know they preggo yet and still drink alcohol etc .
- *
Fetal period: __ weeks after FDLNMP
10
8 weeks after fertilization
Nulliparous - ?
never pregnant
Primiparous - ?
first pregnancy
Multiparous - ?
delivered more than one child
Gravid = ?
pregnant
Gravida = ?
total number of pregnancies, regardless of outcome
delivered pregnancy or not
Parity= ?
number of births
Parity includes what type of births ?
full term
preterm
abortions
living children
Preterm births: Weighing ____ or more, at OR beyond __ completed weeks, alive or dead
500 g
20
Abortions: Ending before __ weeks, induced or spontaneous
20
Twins = ___ gravid event, but ___ parity
one
two
Ex: G2 P3 Ab 0 ?
(had twins once)
Ex: G2 T1 P0 A0 L1 ?
(currently pregant)
Live birth – ?
evidence of life
Infant: Live-born human, from moment of birth until ?
1 year of age
Preterm infant: Born at _____ completed weeks gestation
20 -37
Term infant: Born between ______ and ______ weeks
37 0/7 and 42 0/7
Postterm infant: Born after __ weeks
42
Large for gestational age (LGA) – aka ?
macrosomia - “big body”
Beyond 90th percentile
LGA baby are prone to ?
gestational DM are prone to this
cephalopelvic disproportion
Low-birth-weight infant – ?
2500 g or less
Abortion – based on age or weight: Expulsion of ____________________ with or without fetus
complete or partial placenta
Abortion – based on age or weight: Expulsion of fetus, alive or dead weighing less than _____ or less than __ completed weeks
500 g
20
Embryo –until __ weeks gestation
10
Fetus – ___ weeks
10+
Neonatal period ?
Birth to 28 days of life
Infant is a newborn, a neonate
Perinatal period: __ weeks gestation to 7 days of life
28
before and after birth
Pregnancy Symptoms and Signs: Nausea/vomiting
?
50% of pregnancies
2 weeks until 13-16 weeks
Small, frequent meals, emotional support
Extreme – Hyperemesis gravidarum
Pregnancy Symptoms and Signs: Mastodynia ?
Tingling to pain
Caused by hormones
Pregnancy Symptoms and Signs: Breast engorgement ?
Fullness, esp in primips ( first pregnancies)
Montgomery’s tubercles
Periareolar veins ( venous engorgement )
Pregnancy Symptoms and Signs: Colostrum secretion ?
As early as 16 weeks
variation of normal
Pregnancy Symptoms and Signs: Fetal Movement ?
Perception of fetal movement – “quickening”
18-20 weeks in primips
14 weeks in multips ( recognize it earlier)
Not a reliable symptom
Pregnancy Symptoms and Signs: Elevated basal body temperature ?
Progesterone causes a 0.5ᵒ F increase
Pregnancy Symptoms and Signs: skin changes ?
Chloasma
Linea nigra
Striae
Spinder telangiectasia
Chloasma ?
Darkening of forehead, bridge of nose, cheeks
Exacerbated by sunlight
Linea nigra ?
Midline from umbilicus to pubis
Lightens somewhat after delivery
Spider telangiectasia ?
Vascular stellate lesions
cheek or chest
PUPPP aka ?
Pruritic Urticarial Papules and Plaques of Pregnancy
Most common specific dermatosis of preg ?
PUPP
Most common in primip and multiple gestation ?
PUPP
PUPP description ?
Erythematous papule within striae
- *itchy hive like lumpy within the straie and erythematous and late in the third trimester
- *
When does PUPP start ?
Usually starts late 3rd trimester
Where does PUPP start ?
Starts on abdomen, spreads to extrem
PUPP tx ?
Treat symptoms (pruritus) –low potency steroid cream
** use low potency steroid for the itch**
Pregnancy Symptoms and Signs: pelvic organ changes ?
Chadwick’s sign
Hegar’s sign
Leukorrhea
Pelvic ligaments
Abdominal enlargement
Uterine contractions
What is the Chadwick’s sign
?
Bluish discoloration of cervix and vagina
cause venous engorgement / congestion
What is the Hegar’s sign
?
Widening and softening of body of uterus
Cervical softening and widening of os
Occurs at 6-8 weeks gestation ( early)
What is the Leukorrhea ?
Vaginal discharge ( white , NL , just increased in amount)
Pelvic Organ Changes: Pelvic ligaments ?
Relaxation of sacroiliac and pubic symphysis
Pelvic Organ Changes: Abdominal enlargement ?
Good correlation between fundal measurement and gestational age ( checks fetal growth )
Pelvic Organ Changes: Uterine contractions ?
Braxton-Hick’s – painless, tightening, pressure
Usually begin at 28 weeks
Often stop with walking, exercise
- while true babe they get worse with exercise
- not true labor, its like the uterus is getting ready
Diagnosis: Fetal heart tones FHT’s ?
Handheld Doppler after10 weeks
Fetoscope after 18-20 weeks
Diagnosis: Uterine size/Fetal palpation ?
Uterine enlargement or fetal parts/position
Diagnosis: Imaging studies ?
Sonography
Handheld Doppler after __weeks
10
Fetoscope after_____ weeks
18-20
Sonography ?
Crown-rump length (CR)
top of the head to the butt and very accurate at determine gestational age
Diagnosis: Home pregnancy tests - qualitative ?
First voided morning urine sample
hCG (beta)
Diagnosis: Urine pregnancy tests ?
In office, to confirm
Reliable, rapid, inexpensive
Diagnosis: Serum pregnancy tests - quantitative ?
β-hCG – 6-12 days after conception
Used more for evaluating threatened abortion, ectopic and molar pregnancies
see if it is increasing or decreasing
Uterine size: 8 weeks – ?
fundus at pubic symphysis
Uterine size: 16 weeks – ?
midway between pubic symphysis and umbilicus
Uterine size: 20 -22 weeks – ?
at umbilicus
Uterine size: 18 weeks and up – ?
measure in cms from pubic symphysis to top of fundus
Uterine size: After 36 weeks, ?
height may decrease as head descends into pelvis
** the baby drops and head goes into the pelvis **
______ of pregnancies have complications
5-20%
Prenatal care focuses on prevention and identification of ?
risk factors
Evidence-based that prenatal care helps ? And IDs ?
Helps decrease complications
Identifies high-risk pregnancies for special care
Prenatal Care: Ideally an evaluation occurs before conception ?
Identify risk factors
Discuss smoking, alcohol, teratogens
Discuss nutrition, exercise, vitamins
Start folic acid 3 months before conception
Start folic acid __ months before conception
3
Prenatal Hx: Obstetric history ?
Current symptoms
Outcomes of previous pregnancies
Prenatal Hx: Medical history ?
Preexisting conditions such as :
diabetes, thyroid dz, HTN, epilepsy
Hx of blood transfusion
Prenatal Hx: Surgical history ?
Previous abdominal, gynecologic procedures
Recurrent fetal losses
-cause cervical incompietnce, maybe it dilates to early
Previous Caesarean section
- doesn’t always mean they will need another, VBACS
- vaginal birth after c section
** ( cause we want to know about scar tissue) **
Prenatal Hx: Family history ?
Diabetes, twinning, familial disorders
Prenatal Hx: Social history ?
Tobacco, alcohol, contact with IVDU or other drug use
Exposures – workplace, home
Prenatal Physical Exam: Complete PE at _____ visit ?
first
Prenatal Physical Exam: Pelvic exam ?
Bony pelvis
Fundal height
Cervical length
Cervical os
Pelvic exam: Bony pelvis ?
pelvimetry to assess for cephalopelvic disproportion (CPD).
inside of the pelvic rim measurements
Usually allow a trial of labor, though
Pelvic exam: Cervical length?
3-4 cms average
Pelvic exam: Cervical os?
nullip will be closed
multip may be partially open
Prenatal Blood Tests on First visit ?
CBC - anemia
Blood group, Rh typing
Screen for antibodies against blood group antigens
VDRL/RPR
Hep B surface antigen
Antibodies to rubella and
HIV
Glucose challenge test (if hx of gest diabetes or risk factors for diabetes)
Prenatal Blood Tests: Genetic screening - _________________ and maternal serum to screen for trisomy (21, 18 and 13)
Fetal nuchal translucency
Prenatal Blood Tests: Genetic screening - Serum alpha fetoprotein (AFP) at _____ weeks to screen for open neural tube defects
15-18
Prenatal Blood Tests: Genetic screening - Hemoglobin electrophoresis for ?
sickle cell, CF
Prenatal Blood Tests: Genetic screening - Maternal serum testing – ?
whole panel!
more accurate
material serum is more comprehensive and less scary
Prenatal Blood Tests: Invasive genetic testing -
Must be offered to all women, esp +35 or abnormal family hx or risk factors
Chorionic villus sampling at 9-13 weeks
Amniocentesis at 15-20 weeks
Complication rates are very low and detection for aneuploidy is +99%
Chorionic villus sampling at_____ weeks
9-13
Amniocentesis at ____ weeks
15-20
Prenatal Tests: Urine testing ?
U/A with C&S
At EVERY visit – UA for
Urine testing: Protein- ?
to assess kidneys
Urine testing: Glucose ?
– though not usually significant unless gestational diabetes is present
Urine testing: Ketones ?
– inadequate carb intake
Prenatal Tests: Pap – at initial visit unless ?
normal exam in the past year
Prenatal Tests: _________ – for high-risk patients ?
Tuberculin skin test
Prenatal Tests: STDs ?
Syphilis Chlamydia Gonorrhea Herpes simplex virus - prophylaxis like acyclovir to keep it at bay if they delivery by vag. HIV check prenatally to avoid transmission
Prenatal Tests: Other infections ?
Trichomonas
Candidiasis – often asymptomatic
Bacterial vaginosis – can cause preterm labor, PROM, chorioamnionitis
G can cause eye injuries , premature labor ,
Prenatal Visits: Standard schedule ?
Every 4 weeks from 0-28 weeks
Every 2 weeks from 28-36 weeks
Weekly after 36 weeks
Prenatal Visits: Increased frequency depends on risk factors ?
Maternal conditions, age
Fetal complications
Prenatal Visits: each visit ?
Maternal weight gain Blood pressure Fundal height Fetal heart tones Edema Fetal size and position UA
Maternal Weight Gain: Note ?
prepregnancy weight
Maternal Weight Gain: Woman who is 15% or more below ideal body weight or of short stature is at risk for ?
small for gestational age (SGA) baby
Maternal Weight Gain: ____________ – may have inadequate diet
Adolescents
Maternal Weight Gain: ACOG recommends weight gain of ?
25-35 lbs
Maternal Weight Gain: Obese women should gain ?
less (15-25 lbs) or risk of macrosomia (LGA)
Maternal Weight Gain: Underweight women should gain more ?
(28-40 lbs)
Blood Pressure should be taken while ?
sitting
BP decreases _____ mm in 2nd trimester
5-7
BP should go back to NL in ___ trimester
3rd
BP Elevation may precede __________ ?
proteinuria
Fundal Height Measured at each visit after ?
20 weeks
Fundal Height: If measurement does meet expected amount by more than 2 (cms or weeks) then further evaluation of _______________________ is needed
fetal size and amount of amniotic fluid via US
Fetal Heart Tones ?
Doppler
Fetoscope
Rate, rhythm
-110-160, higher rate earlier in pregnancy
Accelerations, decelerations of rate
Edema: Note any _________ episodes of generalized edema
transient
Edema: Leg edema in late pregnancy is ________
natural
Edema: Edema of upper body – face and hands, esp with ↑ BP may be first sign of ?
preeclampsia
Fetal Size and Position: After 26 weeks – ?
Leopold’s maneuvers
Fetal Size and Position: Persistence of abnormal lie into late pregnancy suggests abnormality ?
If abnormal lie persists, consider ?
Abnormal placenta
Uterine anomaly
Need US
external version after 37 weeks
painful
Third Trimester Evaluations: 1-hour glucose challenge test with a 50 g glucose load at _________ (all patients)
24-28 weeks
check 1 hr glucose
and CBC
Third Trimester Evaluations: Group B streptococcus ?
Universal vaginal and rectal cultures at 35-37 weeks
if pos. give them PCN at labor
and CBC
Group B Streptococcus: Antibiotics to mothers who ?
Have positive cultures
Delivered a prior neonate with group B strep infxn
Had group B strep bacteruria during current pregnancy
Have known risk factors for PROM, prematurity
Women with group B strep who are scheduled for C section before rupture of membranes do not need antibiotics
Group B Streptococcus: __ of neonates exposed to group B strep develop symptoms
2%
so Treat mothers with antibiotics before labor
Neonate sxs GBS ?
Group B Streptococcus
GBS drug of choice ?
Pen G
Cefazolin if penicillin allergy and no hx of anaphylaxis with penicillin
Other Issues of Prenatal Care ?
Bathing and swimming are permitted
Douching should be avoided
Smoking ↑ risk of IUGR, placenta previa, placenta abruption, preterm birth
Alcohol can cause FAS even with 2 oz/day
fetal alcohol syndrome
Exercise encouraged, esp yoga
Immunization to pregnant women ?
killed, toxoid or recombinant vaccines okay. Encourage flu shot. NO live vaccines
**no live vaccinate like MMR, varicella **
Intercourse in pregnant women ?
okay unless pain or bleeding occurs
______ is permitted (auto, train, plane) in pregnant women
Travel
Prenatal Care: Nutrition ?
balanced diet, prenatal vitamins
Nutrition: 127 lbs prepregnant = ?
2300 kcal/day
Nutrition: Additional ___ kcal during pregnancy
300
Nutrition: Additional ___ kcal during breastfeeding
500
Imaging in Obstetrics: Safe
Widely available ?
Primary modality is 2-D US
Imaging in Obstetrics: Good for certain circumstances
Too costly for routine use ?
3D/4D US and MRI available
- *good if you expect abnormality like cleft palate
- *
Imaging in Obstetrics: Limited use because of safety issues
May be necessary in some maternal conditions ?
CT
Ultrasound Imaging options ?
Transabdominal or transvaginal probe
Choice depends on what is being evaluated
US: cervix or early gestation choice ?
transvaginal
US: fetus in 3rd trimester choice ?
trans abdominal
First Trimester US Indications ?
Confirm intrauterine pregnancy
-and location so it is good for ectopics
Assess pelvic pain and bleeding
Estimate gestational age
Confirm viability ( HR)
Determine number of gestations
Genetic screening
Evaluate basic anatomy
Nuchal translucency - downs syndrome
Assess uterine and adnexal anomalies
Second and Third Trimester US screens for ?
Fetal anomalies
Fetal growth – BPD, HC, AC,
femoral length
Fetal well-being (next slide)
Fetal lie and presentation
Placental anomalies
Cervical insufficiency
Gestational age
Number of gestations
Viability
**bi-parietal diameter for hypocephalus etc.
Head circumference and abdominal circumference **
Fetal Well-Being: BPP ?
Biophysical profile (BPP)
4 US parameters and a nonstress test
Scored 0-10/10
Fetal Well-Being: Fetal Doppler exam ?
Measure of speed that blood is moving in a vessel (artery or vein)
US for Cervical Evaluation ?
Shape and length
Most helpful earlier in gestation
Can help determine risk for preterm labor
Determine need for progesterone or cerclage
Non-stress test ?
two or more fetal HR accelerations peak at least 15 beats per minute above the baseline and last 15 seconds from baseline to baseline w/in 20 minute period w/ or w/o fetal movement discernible by the woman
Amniotic fluid volume ?
A single 2 cm x 2 cm pocket is considered adequate of AFI greater than 5 cm
Fetal breathing movements ?
One or more episodes of rhythmic fetal breathing movements of 30 seconds or more w/in 30 minutes
Fetal movements ?
At least 3 discrete body or limb movements.
Episodes of continuous movement are considered as a single movement
Fetal tone ?
One or more episodes of extension of a fetal extremity or trunk with return to flexion, or opening or closing of a hand
