A twin is one of two offspring produced in the same pregnancy. Twins can either be monozygotic (in common parlance, "identical"), meaning that they develop from one zygote that splits and forms two embryos, or dizygotic ("fraternal") because they develop from two separate eggs that are fertilized by two separate sperm.

Fraternal or dizygotic twins usually occur when two fertilized eggs are implanted in the uterus wall at the same time. When two eggs are independently fertilized by two different sperm cells, fraternal twins result. The two eggs, or ova, form two zygotes, hence the terms dizygotic and biovular.

Monozygotic or identical twins occur when a single egg is fertilized to form one zygote which then divides into two separate embryos.

Placental structure/Placental function

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Chorionic villi extend into decidua

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Fetal blood circulates through chorionic villi

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Maternal blood bathes outer surface of chorion

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Maternal and fetal blood doesn’t mix; diffusion transports molecules across membrane

• Endocrine - produces estrogen, progesterone

• Metabolic

• Gas exchange

• Nutrient exchange

• Excretion

• Storage

Patterns of Inheritance

Dominant

One copy of abnormal gene produces trait

One parent with a dominant trait has 50% chance of

passing trait on to child

Recessive

Two copies of abnormal gene required to produce trait

Two healthy parents, each with a gene for the same recessive trait, have 25% chance of passing trait on to child

X-linked

One copy of abnormal X can produce trait in male

One copy of abnormal X usually causes no effect in female (d/t normal opposing X)

• Conduit containing the vessels that connect fetus to placenta

• 2 arteries (unoxygenated blood leaving fetus)

• 1 vein (oxygenated blood going to fetus)

• Surrounded by clear gelatinous material - Wharton’s jelly

Fetal membranes - two layers

• Chorion - maternal side of placenta

• Amnion - fetal side of placenta and continuous with umbilical cord

• Function - retains amniotic fluid, allows for diffusion

Amniotic fluid

• 500-1500 mL of fluid at term

• Oligohydramnios - too little (< 500) - think urinary

problem or chronic stress

• Polyhydramnios - too much (> 2000) - think gastrointestinal

problem, observe for preterm labor

• Function - cushions, provides warmth

Fetal circulation

• Oxygenated blood arrives from placenta via umbilical

vein, bypassing liver through ductus venosus

• Oxygenated blood travels through heart to head and

body, bypassing lungs through foramen ovale and ductus

arteriosus

• De-oxygenated blood returns to placenta via umbilical arteries (branching off femoral arteries)

Types

•Threatened - vaginal bleeding noted
•Inevitable - membranes rupture, cervix dilates
•Incomplete - some products of conception expelled,
some remain
•Complete - all products of conception expelled
•Missed - fetus dies, but is retained
•SABs become a risk factor after 3 or more - evaluate for incompetent cervix or genetic disorder

                         Types
•Total - cervical os covered by placenta
•Partial - cervical os partially covered by placenta
•Marginal - edge of placenta is at edge of cervical os
                   Classic S/S
•Bright red, painless vaginal bleeding
•Management
•Bedrest, pelvic rest, ready access to hospital, fetal
evaluation
•Cesarean section if unresolved by term (sometimes
as the uterus grows, the placenta moves away from
the os)
•Primary concern r/t hemorrhage & fetal oxygenation

                                   Types
•Partial separation
•Complete separation
                              Classic S/S
•Hard, board-like abdomen, with painful, frequent
uterine contractions; may present with vaginal bleed-
ing, but bleeding may be concealed
                             Management
•Hospitalize, administer tocolytics, plan for immedi-
ate delivery if fetal stress is evident or bleeding is
excessive
•Primary concern hemorrhage & fetal oxygenation

Chromosomal analysis

screening tests

Tests of fetal well-being (neurologic, gas exchange)

Non-stress test (NST)

•Basis - a healthy fetus with an intact CNS will accelerate it’s heart rate with movement 90% of the time
Interpretation 
•Reactive - 2 or more 15x15 accels in 20 min
•Nonreactive - no accels, or less than 15x15
•Unsatisfactory - quality of tracing inadequate
•Vibroacoustic stimulation test - used to elicit fetal
movement

•Basis - a healthy uteroplacental connection will sustain a fetus through the stress of labor; an inadequate connection will result in decelerations r/t hypoxia
Interpretation
•Positive - late decels with > 50% of contractions
•Negative - no late decels
•Equivocal - some late decels or hyperstimulation

•Assess risk factors
•Monitor BP, urine for protein, weight gain, related S/S
•Headache, visual disturbances, epigastric pain
•Assess deep tendon reflexes (DTRs) to evaluate CNS
excitability
•Evaluate I&O
•Volume is of concern r/t pathophysiology
•At risk for oliguria and pulmonary edema
•Medication clearance depends on renal excretion
•Medications
•Hydralazine, labetalol, or nifedipine
•Used when systolic > 180 or diastolic > 110
•Magnesium sulfate (seizure prophylaxis)
•Loading dose of 4-6 g bolus, followed by
•Continuous infusion at 2-4 g/H
•Laboratory evaluation
•Hematologic, liver function, renal function

•Assess risk factors
•Monitor urine glucose, weight gain, fetal well-being
•Encourage compliance with screening protocol
•1H oral glucose tolerance test (OGTT)
•50 g glucola followed in 1H by glucose test
•If 140-190 mg/dL, 3H OGTT recommended
•3H OGTT
•Fasting glucose
•100 g glucola followed by hourly glucose tests
•Diagnostic for GDM if 2 or more values
•Fasting value ≥ 95 mg/dL
•1 hour value ≥ 180 mg/dL
•2 hour value ≥ 155 mg/dL
•3 hour value ≥ 140 mg/dL

•Encourage diet and exercise appropriate to aid uptake of glucose
•Monitor and instruct on insulin therapy and glucose
monitoring as indicated
•Encourage compliance with fetal surveillance
•Weekly NSTs and/or BPP
•Encourage and teach fetal kick counts
•Insulin drip may be indicated during labor - monitor patient carefully as intake may vary with labor
•Consider possibility of macrosomic baby at delivery -
notify neonatal team
•Confirm fetal lung maturity by amniocentesis if elective
delivery is planned at less than 39 weeks gestation

•Normal pregnancy requires a gradual move towards insulin resistance in order to supply the placenta and fetus with enough glucose
•Relative sensitivity to insulin occurs in the first half of
pregnancy
•As the fetus grows in the second half of pregnancy, in-
creasing resistance to insulin helps provide the necessary glucose to the fetus
•Normal response is to increase insulin; in women with
GDM, this ability to regulate glucose fails
•Systemic pathophysiology r/t complications from DM are similar to the non-pregnant patient; diabetic women are at increased risk for PIH
•The fetus is at increased risk due to the high levels of
glucose (poor placental perfusion, increased risk of in-
trauterine death, growth abnormalities, macrosomia)

•Problems r/t the normal changes of pregnancy  increased plasma volume, venous return, and cardiac output
•Mitral valve prolapse (stenosis)
•Prophylactic antibiotic therapy

Class 1 and 2 cardiac disease
•Limit physical activity, avoid excessive weight gain
•Prevent anemia and infection
•Monitor fetus and assess for developing problems
Class 3 and 4 cardiac disease
•Prevent cardiac decompensation and CHF
•Protect fetus from hypoxia and IUGR

Goals of care - promote cardiac output adequate to meet maternal/fetal demands
•Nursing and medical care focuses on minimizing effects of labor
•Manage IV fluids to prevent volume overload
•Elevate upper body
•Provide oxygen
•Provide epidural (and sedation) to reduce discomfort

•Defined as Hgb < 10  mg/dL or Hct < 33%
•Iron deficiency - most common
•Folic acid deficiency (megaloblastic) - often associated
with iron deficiency anemia
•Treat (prevent?) with iron and folic acid

Tissue enzymes dependent on iron can affect cell function in nerves and muscles. The fetus is dependent on the mother's blood and anemia can cause poor fetal growth, preterm birth, and low birthweight.

•All women should be offered screening and counseling
•Pregnancy not  encouraged - 90% of pediatric cases are d/t perinatal transmission
•Frequency of transmission ranges from 20-30%
•Treatment of mother with AZT during pregnancy,
and

Treatment of infant for 6 weeks after birth can re-
duce transmission rate to 8-10%
•Method of delivery - no clear answer; both vaginal and
cesarean methods involve risks

•CDC recommends screening all pregnant women at 35-
37 weeks gestation
•Prophylactic antibiotics for women who are
•Previous infant born with GBS infection
•GBS positive culture this pregnancy
•GBS bacteriuria this pregnancy
•GBS status unknown but with risk factors
•Delivering at < 37 weeks gestation
•ROM ≥ 18 hours
•Maternal fever ≥ 100.4°F

Resuscitation of mother is goal - without mother, fetus will suffer
ABCs
•Airway & breathing - support oxygenation
•Circulation - indications for CPR are unchanged
•Tilt patient (keeping c-spine cautions as indicated) to
relieve aortocaval compression
•Treat shock according to cause
•Assess fetal status

•Visceral - pertaining to organs, abdomen in particular
•Cervical dilation, tissue ischemia, afterpains
•Somatic - pertaining to body
•Pushing, pulling sensations
•Distention of vagina and perineum during expulsion

                     Physiologic effects
•Increased metabolic rate and demand for oxygen
•Increased production of catecholamines, cortisol,
glucagon
•Less oxygen/waste exchange for fetus

                    Psychologic effects
•Inability to relax, disruption of labor progress
•No interaction with infant
•Unpleasant memories
•Inadequate feelings of partner

                  Advantages
•Least level of intervention
•Independent action on part of patient or nurse
•Helps patient retain sense of control
                   Methods
•Relaxation
•Cutaneous stimulation
•Mental stimulation
•Breathing

                     Advantages
•Excellent pain relief with good relaxation
•Varying dosage and methods allows exibility in
level of block, duration of analgesia/anesthesia
                   Disadvantages
•Higher level of intervention, risk
•Need for IV, foley catheter restriction of movement
•Reduced sensation to bladder, perineum
•Onset may be slow depending on method
•Analgesia may be ineffective

              Systemic medications
•Medications go to fetus; after birth considerations
•Nausea, sedation, adverse reactions
               Regional medications
•Decreased sensation (urination, pushing, ambulation)
•Hypotension
•Headache
•High block
•Positioning considerations
•Ongoing assessment - mom/fetus

•Labor - cervical changes and uterine contractions occur-
ring between 20 and 37 weeks gestation
•Birth - delivery before 37 weeks gestation (20-36 6/7)
•Risk - at least 50% have no risk factors

Initial measures
•Identify and treat infections
•Restrict activity
•Hydration, hydration, hydration

•Goals: delay birth to allow optimal fetal lung maturity
•Tocolytics
•Beta-adrenergic agents - Ritodrine, Terbutaline
•Side effects of drug mimic sympathetic nervous
system (sympathomimetics):
•Tachycardia, shortness of breath, chest pain,
hyperglycemia, hypokalemia
•Magnesium sulfate
•Side effects r/t drug properties, clearance
•Metallic taste, warm feeling, diminished
reflexes, malaise
•Prostaglandin synthesis inhibitors - Indomethacin
•Avoid after 32 weeks gestation d/t risk of pre-
mature closure of ductus arteriosus
•Calcium antagonists - Nifedipine
•Often used sublingually for patients who cannot
tolerate SE of PO Terbutaline
•Stimulate fetal lung maturity
•Corticosteroid therapy

•Assess for labor progress
•Careful respiratory and cardiac assessment r/t properties
of tocolysis
•Preterm labor patients at higher risk for ARDS
•Although hydration is important, over-hydration
places patient at risk for ARDS
•Careful I&O
•Provide teaching and orientation to NICU
•Referrals for social service, neonatology
•Allow for expressions of emotions (grief, concern, guilt)

Indications for labor induction:  Any condition where con-
tinuing pregnancy may jeopardize health of mom or baby

Contraindications to labor induction:  Any contraindication to labor or vaginal birth

Methods of Induction

Cervical ripening

                             Oxytocin
•Typical concentration 20 or 30 units/1000mL, IVPB to port closest to patient
•Dose initiated in milliunits/minute, IV, titrated according to maternal/fetal response
                           Risks
•Uterine hyperstimulation with subsequent
evidence of fetal stress
•Uterine rupture, water intoxication, postpar-
tum hemorrhage

 (artificial rupture of membranes - AROM)
             Risks
•Infection
•Umbilical cord prolapse - increased risk
where
•Presenting part at high station
•Poor fit of fetus in pelvic inlet
•Excessive amniotic fluid (hydramnios)

•Assess maternal/fetal response to medication
•Baseline, ongoing, and with every change in dose
•Assess I&O, monitor for uid overload
•Where hyperstimulation and/or fetal stress noted
•Stop oxytocin (keep mainline open)
•Turn patient to side (optimal uterine perfusion, slows
UCs)
•Oxygen (optimal oxygen delivery to placenta)
•Increase rate of primary IV (aids delivery of oxygen)
•Assess labor progress
•Notify MD

relationship of "P"s of labor to labor dysfunction

                      Passenger
•Fetus is large or positioned in a non-optimal manner
•Attitude - extended or military
•Lie - transverse
 Position - posterior
•Presentation - face or brow, shoulder, breech
                        Passage
•Uterine abnormalities - bicorunate uterus, etc
•Pelvis - shape, mobility
                        Psyche
•Fear, anxiety, labor fails to meet expectations

•Enhance uterine contractions through
•Positioning, ambulation
•Administering induction/augmentation agents as
ordered (see induction/augmentation)
•Optimize fetal/pelvic fit through encouraging rocking,
squatting, hands and knees positioning, use of gravity
•Teach, explain, support to allay fears and anxiety
•Provide options for pain relief, sleep
•Assess mother and fetus for tolerance of labor, watching
for evidence of stress; promoting optimal oxygenation

cystic fibrosis r/t vitamin replacement, pancreatic enzymes

In cystic fibrosis (CF), the ducts in the pancreas become clogged with thick, sticky mucus. This mucus blocks the

enzymes from reaching food in the small intestine. This can lead to poor digestion and absorption of food, as

well as problems with weight gain.

Pancreatic enzyme replacements are available to help people with CF digest and absorb their food.

respiratory r/t peak flow meter use

morphine IV vs oral dosing

Oral: 0.2 to 0.5 mg/kg/dose every 4 to 6 hours 

IV: 0.05 to 0.2 mg/kg/dose (up to 15 mg) every 4 hours as needed

techniques, teaching, implications r/t Hickman Broviac catheter

 a temporary IV line placed into a vein in the child's chest. is designed for long-time use

Dressing changes should be done every day for the first seven days, then on Mondays, Wednesdays and Fridays, or as needed. If the dressing becomes loose, dirty or wet, it must be changed immediately.

When the catheter is not in use, each line must be flushed through the cap every day with Heparin

Cap changes should be done once a week

iron administration and therapy side effects

either oral or IV

Constipation; darkened or green stools; diarrhea; nausea; stomach upset; vomiting.

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); black, tarry stools; blood or streaks of blood in the stool; severe or persistent vomiting or stomach pain.

Right lower quadrant abdomen

pain
Fever
Rigid abdomen
Vomiting
Constipation or diarrhea present
Anorexia

In a person with leukemia, the bone marrow makes abnormal white blood cells. The abnormal cells are leukemia cells.

Unlike normal blood cells, leukemia cells don't die when they should. They may crowd out normal white blood cells, red blood cells, and platelets. This makes it hard for normal blood cells to do their work.

Most patients with leukemia are treated with chemotherapy. Some patients also may have radiation therapy and/or bone marrow transplantation

• Lethargy or drowsiness, Confusion or giddiness, Headaches, Hallucinations, Visual changes, including aberrations in color vision and yellow halos around lights, transient amblyopia or scotomata, and decreased visual acuity, Seizures, Syncope, Nausea and vomiting, Diarrhea, Anorexia, weight loss, or failure to thrive, Abdominal pain

•  

• General supportive care of digitalis toxicity includes hydration with intravenous (IV) fluids, oxygenation and support of ventilatory function, discontinuation of the drug, and sometimes the correction of electrolyte imbalances.

sickle cell characteristics, diagnosis

an autosomal recessive genetic blood disorder with incomplete dominance, characterized by red blood cells that assume an abnormal, rigid, sickle shape. Sickling decreases the cells' flexibility and results in a risk of various complications. The sickling occurs because of a mutation in the haemoglobin gene.

In HbSS, the full blood count reveals haemoglobin levels in the range of 6–8 g/dL with a high reticulocyte count (as the bone marrow compensates for the destruction of sickle cells by producing more red blood cells).

Hodgkin's disease

Hypovolemic: 

Most common type of shock in children. 
Caused by decrease in blood volume or circulation
Caused by:  trauma, surgery, burns, vomiting, diarrhea,

Distributive: 

Abnormality in distribution of blood flow. 

Septic shock is most common type. 

Cardiogenic:

Cardiac output doesnt match body needs. 
Decreased cardiac output.
Decreased BP, poor tissue perfusion