Obstetrics - Normal Pregnancy + Prenatal care Flashcards
Embryo vs fetus
< 8 weeks = embryo
> 8 weeks = fetus
1st vs 2nd vs 3rd trimester
1st - 0-12 wks
2nd - 12-28 wks
3rd - 28 - delivery
< 24 weeks - previable
24-37 weeks - preterm
> 37 weeks - term
Signs of pregnancy
Bluish discoloration of vagina and cervix (Chadwick sign)
Softening and cyanosis of the cervix at or after 4 wk (Goodell sign)
Softening of the uterus after 6 wk (Ladin sign)
Physio of pregnancy - CV
cardiac output increases by 30% to 50%.
- The increase in cardiac output is first due to an increase in stroke volume and is then maintained by an increase in heart rate as the stroke volume decreases by the end of the third trimester.
Systemic vascular resistance decreases —> decrease BP
- most likely 2/2 elevated progesterone, leading to smooth muscle relaxation.
Physio of pregnancy - Pulm
The increased minute ventilation during pregnancy causes a compensated respiratory alkalosis.
Will have dyspnea
Increase:
Tidal volume
Minute ventilation (b/c inc tidal volume but RR stays same)
INspiratory capacity
Decrease:
TLC (2/2 elevation of diaphragm)
Functional residual capacity
Constant:
RR
Plasma osmolality is decreased during pregnancy which increases the susceptibility to pulmonary edema. - Common causes of acute pulmonary edema in pregnancy include tocolytic use, cardiac disease, fluid overload and preeclampsia.
Physio of pregnancy - Heme
Increase:
Plasma volume
RBC volume (less than plasma volume)
Coagulability
Decrease:
Hct (plasma volume»_space; RBC vol) —-> dilutional anemia
Physio of pregnancy - Endo
Increase:
TBG (stimulated by estrogen) —->
TOTAL T3, T4
Same:
Free T3, T4
Physio of pregnancy - MS
spider angiomata
palmar erythema secondary to increased estrogen levels
hyperpigmentation of the nipples, umbilicus, abdominal midline (the linea nigra), perineum, and face
(melasma or chloasma) secondary to increased levels of the melanocyte-stimulating hormones and the steroid hormones.
Carpal tunnel syndrome
Prenatal visits
- what is done?
Blood pressure, weight, urine dipstick, measurement of the uterus, and auscultation of the FH are performed and assessed on each follow-up prenatal care visit.
The FH is usually first heard during the
second trimester, as is the first fetal movement
patients who are Rh negative should receive Rho-GAM at _____ weeks.
28
Prenatal visit increments
Prenatal visits increase to every 2 to 3 weeks from 28 to 36 weeks and then to every week after 36 weeks.
Beyond 32 to 34 weeks, Leopold maneuvers are performed to determine fetal presentation
In women with latent herpes simplex virus (HSV), antiviral prophylaxis can be initiated at ____ weeks.
36
Active HSV would be an indication for cesarean delivery.
Occasional irregular contractions that do not lead to cervical change are considered
Braxton Hicks contractions
dehydration in preggers can lead to
uterine contractions, possibly secondary to cross-reaction of vasopressin with oxytocin receptors
BPP looks at five categories and gives a score of either 0 or 2 for each:
amniotic fluid volume, fetal tone, fetal activity, fetal breathing movements, the nonstress test (NST), which is a test of the FHR.
A BPP of 8 to 10 or better is reassuring.
Blood flow in the middle cerebral artery is used when evaluating for
fetal anemia in the setting of Rh isoimmunization
On fetal monitoring, late FHR decelerations are concerning for
uteroplacental insufficiency
At ____ weeks, screening for group B streptococcal
infection is also performed.
35-37 weeks
Patients who have a positive culture should be treated with intravenous penicillin when they present in labor to prevent potential neonatal group B streptococcal infection
Gestational diabetes - risks
Intrauterine growth restriction is typically seen in women with pre-existing diabetes and not with gestational diabetes.
Shoulder dystocia, metabolic disturbances, preeclampsia, polyhydramnios and fetal macrosomia are all associated risks of gestational diabetes
Accurate GA dating is made by
Certain LMP c/w first or second trimester US
dating by 3rd trimester US or unsure LMP is more suspect
How do you get a di-di pregnacy?
Separation of ovum prior to differentiation of trophoblast
will get 2 amnions and 2 chorions
How do you get mono-di pregnancy?
Separation of ovum after trophoblast differentiation adn before amnion formation
will get 1 chorion adn 2 amnions
How do you get mono-mono pregnancy?
Separation of ovum after trophoblast differentiation and after amnion formation
1 chorion
1 amnion
Division of cells beyond what day will give you singleton fetus?
15-16 days
GBS screening
Tx
35-37 weeks
Cx of vagina and rectum
Tx w/ IV penicillin G at time of labor or ROM
- If status unknown and labor prior to 37 wks GA or ROM > 18 hrs –> tx with PXN G
- also can use cefazolin (ancef) if PCN allergic
- Vanco for GBS resistant to clinda or unknown susceptibility
Screen for gonorrhea
1st prenatal visit and 3rd trimester
Screening for syphilis
VDRL or RPR
If +
- send titer
- confirm with FTA-Abs to r/o false + (SLE, antiphosphlipid ab syndrome)
Morning sickness resolves by week
16
Patients who desire non-invasive assessment of their risk for aneuploidy can have
first trimester screen (a fetal nuchal translucency (NT) measurement and a maternal serum PAPP-A)
- if +, can have detailed fetal US and echo at 19-20 weeks to r/p anomalies if doesn’t want an amnio or CVS
a second trimester quadruple screen.
Ibuprofen is safe to take until around
32 weeks gestation, when premature closure of the ductus arteriosis is a risk
Progesterone in pregnancy
> 25 ng/ml suggests healthy pregnancy
bHCG levels in pregnancy
Should rise by at least 50% every 48 hours until the pregnancy is 42 days old
after that time, the rise in level may not follow the curve
Nonstress test
assessment of fetal well-being that measures the fetal heart rate response to fetal movement.
nl = two fetal heart rate accelerations of 15 beats/minute for 15 seconds within 20 minutes.
Vibroacoustic stimulation is not indicated unless the NST is non-reactive.
Contraction stress test
assesses uteroplacental insufficiency and looks for persistent late decelerations after contractions (3/10 minutes)
Methods to date a pregnancy - best methods
1st trimester
1st trimester
- US measurement of crown-rump length is best
Chorionic villus sampling vs amniocentesis
Chorionic villus sampling (CVS)
- performed between 10 and 12 weeks gestation
- use FISH to analyze cells
- increased risk fetal death and limb reduction defects
- limb reduction defects occurs when procedure carried out before 9-10 wks GA
Amniocentesis
- performed after 15 weeks
Gold standard to eval cervix for incompetence in pregnancy
Transvaginal US
length < 10th % for GA is short cervix
Exercise contraindicated in pregnancies with…
Amniotic fluid leak Cervical incompetence Mult gestation Placenta abruption Placenta previa Premature labor Preeclampsia Gestational HTN Severe heart or lung dz
Nl amniotic fluid pH
neutral 7-7.5
Cause of low back pain in third trimester pregnancy
Increase in lumbar lordosis
Relaxation of ligaments supporting joints of pelvic girdle
