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Prenatal Care Lecture 5. SCREENING TESTS 1. AFP 2. Triple Marker Test 3. Quad Test Blood serum test P robability of anomaly. If +, amniocentesis offered. . AFP screening: (alpha-fetoprotein) Screening
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Prenatal Care Lecture 5
SCREENING TESTS • 1. AFP • 2. Triple Marker Test • 3. Quad Test Blood serum test • Probability of anomaly. • If +, amniocentesis offered.
AFP screening: (alpha-fetoprotein) Screening • 1st developed to detect abnormalities in women younger than age 35 • AFP made by fetal liver and yolk sac. • Secreted from fetal to maternal circulation AND to amniotic fluid from kidney into amnion. • Detects open neural tube defects, anencephaly, Down’s syndrome. • Abnormal concentrations may indicate serious fetal anomalies; requires additional testing.
Common Possible Indications : • High AFP= open neural tube defects • Low AFP = trisomies (Down’s syndrome). • 15 -18 wks of pregnancy. Limitations are: • 1) False + causes ^ anxiety/expense when F/U tests needed. • 2) Women who don’t seek prenatal care til > 18th wks miss opportunity for AFP screening. • 3) Results dependent on maternal weight: low maternal wt. > high AFP; high maternal wt. > low AFP
Triple Marker Test • measures AFP, hCG, & unconjugated estriol. • developed after AFP. • higher rate of anomaly detection than AFP. • high false positive rate 7-9% • Common reason for false + is misdated pregnancy. Negative result not indicative of NO risk. Indicates LOW risk.
Quad Test • replacing Triple Test as standard screening test • Better at detecting more cases of Down syndrome, trisomy 18, 21, & neural tube defects • Decreased false positive rate. • uses 4 serum assays (AFP, hCG, unconjugated estriol, & dimeric inhibin A [DIA]) • DIA ^ with Down syndrome fetus. • Performed between 15 - 22 wks (16-18 wks. optimum).
CVS – Chorionic Villus Sampling Allows early screening (1st trimester) @ 10 wks. • Cells from chorionic villi - same genetic makeup as fetus. Early screening. • Results in 48 hrs. - eliminates 2nd trimester AB • risk of miscarriage - 1/100 • ultrasound guides trans-cervical catheter or trans-abdominal needle into placenta. • Chromosomal & DNA analysis done on fragments. • Best @ 10-12 wks to avoid fetal harm.
Ultrasound– high frequency sound waves converted to 2 dimensional images. No X-ray hazard; fetal structures seen. 1st trimester : confirms pregnancy, viability (locates heartbeat), verify dates/gestational age, size, detects twins, r/o ectopic vs. intrauterine pregnancy [IUP]. IUD. Placenta previa. 2nd & 3RD trimesters confirm location of placenta, confirm gestational age, determine fetal position, monitor fetal movements, evaluate amniotic fluid, locate fetus prior to & during amnio/CVS.
External Fetal Monitoring Detects uterine contractions & FHR - continuous or intermittent. External sensors: Contractions - toco transducers FHR - cardio-transducers. Maternal movements can cause loss of FHR pick up.
Internal = more precise Fetal scalp electrode – wire onto fetus scalp. FHR recorded on graph paper. Normal FHR 110-160 bpm. Intrauterine pressure catheter (IUPC) = probe alongside fetus. Attached to pressure sensor; intensity of uterine contractions measured accurately.
Non-Stress Test: {EFM} toco & cardio Records FHR, accels., decels., fetal movement. One movement q 10-20 min. Reactive NST = 2 FHR accels. > baseline by 15 bpm lasting longer than 15 sec. within 20 min. Daily fetal movement count: uninvasive; inexpensive; done @ home; 10 FM/30 min. If not, eat snack, count again. Near due date more serious if low fetal movement. See MD if ↓ FM.
Biophysical Profile (BPP) NST & ultrasound to evaluate fetal well-being. 5 factors assessed: • 1] fetal muscle tone; 2] FM; 3] fetal breathing movements; 4] Amniotic fluid volume; 5] FHR reactivity. • Score of 2 on each; score 6 = equivocal. Score 8-10 = “reassuring”. • Amniotic Fluid Index = AFI = measures fluid in 4 quadrants. > 5 “reassuring”; 5 or < is not. • Assesses long term placental func.
Amniocentesis: Removal of amniotic fluid from abdomen between 14 -16th wk. New techniques 12 wks. 1st – 2nd trimester: R/O chromosomal abnormal 3rd trimester: fetal lung maturity - less than 37 wks Fluid removed & analyzed. Risk of miscarriage ~ 1/200. Assess for labor. Rh (-) mother gets Rhogam. Assess for contractions x 30 min.
Amniotic fluid assessment: Cytogenetic testing (karyotyping) - chromosomal abnormalities. • Fetal lung maturity: Lecithin & sphingomyelin: lipoproteins keeps alveoli open @ birth. L/S ratio 2:1 adequate. • Steroids - ↑ rate of fetal lung maturity [24-34 wks] for PTL. Betamethasone: 12 mg x 2 q 24 hr. Dexamethasone: 6 mg q 6 hr x 4. IM inj. • Accelerates production of surfactant. • Full-term baby's lungs already make surfactant • Lubricates lining of air sacs & prevents sticking of membranes. Good air exchange.
Intrauterine surgery:Cesarean birth/cesarean section = C/S. Birth by abdominal incision into uterus. Can be more complicated than vaginal birth. Considered one of safest surgeries when compared to other procedures. Overall C/S rate: ~ 40%. [higher in NYS].
Major Indications for C/S: • Active genital herpes • Overgrowth of genital warts • CPD (cephalopelvic disproportion) • Severe HTN (toxemia) • Failure to progress • Previous C/S w vertical incision • Placenta previa • Abruption • Umbilical Cord Prolapse • Macrosomia • Breech, Transverse fetal lie • Fetal Distress
Prenatal Terms Perinatology: high risk conditions of pregnant woman/fetus. Neonatology: dx/tx of neonates. • Gestation: weeks since 1st day of LMP. • Abortion: < 20 wks. • Preterm or premature labor: > 20 wks; < 37 wks. • Full-term: 37-41 • Postdates: > 41 wks.
Prenatal Terms cont. • Antepartum: between conception & onset of labor • Intrapartum: onset of true labor until delivery of infant & placenta. • Postpartum: delivery until woman’s body returns to pre-pregnant condition [6 wks.]
Prenatal Terms – cont. • Gravida: Any pregnancy, regardless of duration, includes present pregnancy. • Para: birth > 20 weeks • Primigravida: pregnant for 1st time. • Primipara: birth to one child past age of viability. • Multigravida: 2nd or subsequent pregnancy. • Multipara (multip): 2 or more deliveries >20 wks. • Nulligravida: never been & currently not pregnant. • Nullipara: has not had delivery at more than 20 wks. • Stillborn: fetal demise > 20 wks gestation.
Client Profile (client hx) 1) Maternal age @ 1st prenatal visit. • Current pregnancy [1st , 2nd, 3rd] • LMP? cramping?, bleeding ? Planned? 2) OB Hx: past pregnancies, abortions, living children, types of deliveries; complications; birth wts. Blood type/Rh factor, childbirth education classes. • Gravida = total pregnancies [include current pregnancy] • Para: pregnancies > 20 weeks.
TPAL - breakdown of Gravida/Para T = term infants P = preterm infants (> 20 & < 37 wks) A = abortion (spontaneous or elective ≤ 20 wks.) L = living children
3) Gynecologic Hx: age @ menarche, length of flow, length of cycle [# days bet periods] Fibroids? Infertility? Tubal surgery? Previous C/S? 4) Current medical history 5) Past medical history 6) Family medical history: pertinent hx; genetic diseases? 7) Partner’s Hx: same 8) Personal: ETOH, tobacco, drugs, depression, anxiety, etc. 9) Medications [pt. taking now] 10) Age
Multiple gestation • Twins - same as single fetus; may attempt vaginal del; close monitoring near term. • Triplets – close monitoring; scheduled C/S.
Initial Physical Assessment • 1st prenatal visit - establish baseline data • helps develop health care planning strategies. • Time for health teaching: wt. gain, nutrition, exercise, & potentially detrimental habits: smoking, ETOH, etc. • Do ROS; health history; & physical exam…
Physical Exam: • VS, UA/C&S, glucose, protein and weight [q visit] • Pap [1st visit & 28 wks.] • CBC, SMA-7, Blood type/Rh, Coombs, titers, VDRL, HIV. Herpes simplex I & II, PPD. +PPD • Do chest x-ray. • + chest x-ray, INH [isoniazid] & vit.B6 x 9 mos. • Do F/U x-ray. Tx active TB right away. May breast feed on TB therapy. Active TB in home, infant on INH as prophalactic.
Manual pelvic measurements: taken now or later [not done if already had vaginal delivery] • Skin –rashes, acne • Head & neck – masses • Vision, dentures, cavities, seizures, headaches • Breast exam: SBE [breast CA] • HTN, heart disease, blood transfusions. • Gastrointestinal • Respiratory
Pelvic exam: Pap; inspect for discharge & odor [monilia, BV] cx trich, GC, Chlamydia, herpes. • Visual inspection of perineum -herpes & condyloma. • Cervical abnormality - tx in 2nd/3rd trimester. • Mental status – anxiety, depression, psych. hx • Support Person: married, separated, FOB involved? • Ultrasound – viability of fetus; heartbeat? • Prenatal visits are: q 4 wks. til 28 wks., q 2 wks. til 36, & q week til delivery. More visits if high risk.
DONE @ subsequent visits: • Triple screen. F/U with Amnio if + • 50 gm. GCT @ 26-28 wks. [1h glucose]. • When is it done if pt. high risk? What makes a pt. high risk? • If + GCT, do GTT. • Rh- moms - get Rhogam
GBS - normal vaginal flora. Can affect pregnancy outcomes. Risks: PT labor, UTI, chorioamnionitis, PP infections, perinatal mortality/morbidity. Do GBS cx @ 36 wks. r/o GBS bacteria [vaginal/rectal] + GBS: tx in labor with multiple doses of antibiotics 4 hrs. before delivery. If < 4 hrs, baby has CBC & bl. Cx + Maternal temp, infant goes to SPC/NICU. Untreated GBS: greatest cause of neonatal sepsis & meningitis.
Abdomen - measured q visit. • Fundal height measurements start @ 10-12 wks. • 10 – 12 wks: slightly above symphysis pubis • 16 wks: ½ bet symphysis & umbilicus • 20-22 wks: @ umbilicus • 28 wks: 3 FB above umbilicus • 36 wks: below xiphoid process. • Measured in cm. [tape measure] every visit. • Fetal heartbeats (110-160 beats/min.) • Heard with doppler 10-12 wks.
PRENATAL PERIOD A. Signs & Symptoms of Pregnancy Presumptive- not definitive; other reasons for missed period • amenorrhea- missed period; + PT in 1-2 wks. • N & V [1st trimester] • Urinary frequency d/t growing fetus • Tender breasts [1st sign of preg.] • Fatigue [1st trimes] • Quickening [ 20 wks.] movement felt by mom. [gas?] • Thinning & softening of fingernails [d/t hormones]
Probable - Suggests pregnancy. Not 100% Uterine enlargement : growth of fetus. Goodell’s sign: cervix softens [6-12 wks] Chadwick’s sign: bluish color cervix, vagina, vulva [6-12 wks] Hegar’s sign: softening lower uterine segment [6-12 wks] ↑ skin pigmentation [chloasma; “mask of pregnancy”] • linea nigra: dark vertical line center of abd.; nipples, areola; • striae gravidarum = stretch marks
Braxton Hick’s contractions: periodic uterine tightening • Ballottement: fetus bounces off abd. wall with VE • Positive Pregnancy results: + HCG; urine/blood test; [possible ectopic - not viable]
3. Positive [not attributed to other conditions] Fetal heartbeat [heard by examiner] Ultrasound [by 8 wks. complete fetus seen] Fetal movement [felt by examiner & mom @ ~ 20 wks.]
B. Physiologic Adaptations to Pregnancy 1. Cardiovascular system • Cardiac hypertrophy – heart enlarges ~ 1-2 cm. • Elevation of heart – assumes more transverse position in center of chest. • Progressive ↑ bl. vol. –gradual ↑ d/t placenta & fetal circulation & for hemorrhage prevention @ del. – 40% by 3rd trimes. • Varying resting pulse rates - ↑ by 10 bpm
↑ femoral venous pressure – pt. supine - wt. of growing uterus slows venous return to heart from legs; lightheaded; ankle/leg edema; hypotension. • ↑ fibrinogen levels – 50 % by end of preg. • ↑ levels of bl. coagulation factors ( vii,ix,x) • total ↑ RBC – accommodates fetal circulation • hematocrit drops [both d/t ↑ bl. vol.] • hemoglobin drops • leukocyte prod. -↑ WBC to protect against infection.
2. Gastrointestinal system • Swelling of gums: ^estrogen; ^ vascularity [bleeding of gums] • Lateral/posterior displacement of intestines • Superior/lateral displacement of stomach • delayed intestinal motility: ^ progesterone levels [GI reflux/heartburn] • Hemorrhoids: ^ pressure on rectal veins • Constipation: ↓ gastric motility
GI cont. • Displacement of appendix – upward & outward position; appendicitis common non-obstetrical surgical intervention of pregnancy. • ↓ gallbladder emptying time – re-absorption of bilirubin into maternal circ. > itching • ^ gall stones – d/t ^ plasma cholesterol levels
3). Endocrine system • Basal metabolic rate - ^ by 25% by term. • Slight hyperplasia of thyroid ^ prod. of thyroxine causes ^ BMR • pituitary gland stops producing FSH & LH • posterior pit. produces oxytocin [uterine contx’s] • Increased prolactin, estrogen, progesterone, cortisol, HCS=[hPL] produced by placenta - support placenta. • Insulin resistance –preg. hormones are antagonistic. Excess glucose from mom goes to fetus. • Maternal fat stores used for energy for mother.
4. Respiratory system • ↑ vascularization of respiratory tract [nasal stuffiness] - ^ estrogen • Lungs pushed upward • Upward displacement of diaphragm [rises ~ 4cm] • ↑ tidal volume [air inhaled & exhaled] • [ ↑ progesterone & ↑diaphragmatic excursion] progesterone causes smooth muscle relaxation & vasodilation. • slight ^ RR – 2 breaths/min.
5. Metabolic system • Pregnancy hyper-metabolic state - ^ calories [300/day] • Increase in H2O retention, serum lipids, iron, carbs & lipoproteins. • water level ^ 7.5L in average woman.
Recommended Weight Gain: ~ 25-35 lbs. (average weight & frame) * Each trimester = about 13 weeks so: 1st trimester: 3 lbs. 2nd trimester: 12 – 13 lbs. 3rd trimester: 12 – 13 lbs.
Weight gain distribution: • Fetus: 7.5 lbs. • Placenta: 1.5 “ • Amniotic fluid: 2 “ • Uterus: 2.5 “ • Breasts: 3 lbs. [total] • Bl. Volume: 2-4 lbs. • Extravascular fluid/fat : 4-9 lbs.
6. Integumentary system Pigmentary changes: ^ melanocytes, estrogen & progesterone Hyperactive sebaceous/sweat glands [^ perspiration] Darkening of nipples, areola, cervix, vagina, & vulva [8th wk] Chloasma = melasma = mask of preg. Linea nigra – vertical line along center of abd.
7. Genitourinary system * Kidneys enlarge - meet demands of excretion [mom/fetus] * Dilation of ureters/renal pelvis (kidneys)^ 25%; ^ estrogen * ^ GFR (50%) d/t demands ^ circulation/excretion * ^ clearance of urea & creatinine so: ↓ BUN & creatinine * Glucosuria: ^ GFR, filtration of glucose ^. * Glucose & protein can’t be reabsorbed fast enough so some spills. + Protein more significant than glucose. * ↓ bladder tone [d/t progesterone] ^ urine * Na retention [maintains osmolarity d/t ^ fluid - K not retained]
Genitourinary cont: i. ^ dimensions of uterus: Pre-pregnant Pregnant 65 g. 1,200 g. (wt.) 1.5 ml. 5,000 ml. (vol.) j. ^ vascularity of cervical glands [to prepare for labor] k. ^ vaginal secretions [leukorrhea] [Candida] l. cessation of ovulation [pituitary] FSH & LH stops m. vagina thickens d/t ^ fat deposits & ^ vascularity
C. Psychological Adaptations • Ambivalence – adjustment period; occurs even if planned; 20 wks aka “quickening”. • Acceptance – dreaming about parenting role; man feels preg. symptoms -“couvade” syndrome. • Introversion- concentrates on body changes Extroversion – happy; everyone is paying attention • Emotional lability – hormones changing; crying then happy. Mood swings - normal.
E. Gestational Age Assessment/Estimated date of Confinement (EDD or EDC) • Nagel’s Rule: 1st day of LMP, count back 3 mos, +7 days. Oct. 5 - 3mos. + 7 = July 12 = EDC. • 1st Trimester Measurement:Crown to rump: most reliable. CR • 2nd/3rd Trimester Measurements: • Fetal Biparietal diameter [side to side – most important] • Fetal Head Circumference, fetal abdominal Circumference, Fetal Femur Length.
Fundal height: in cm. with tape measure More Precise Method: • McDonald’s Method - determines duration of preg. in lunar months or weeks. • Fundus [cm] x 2/7 = lunar months. • Fundus [cm] x 8/7 = weeks. *More common Ex. 12 cm x 8/7 = 96/7 = 13 wks. & 5 days Stated: 13 & 5/7 wks.
Counseling on: • Childbirth education [Lamaze] • Dental care • Immunizations [up to date] • Clothing [loose fitting] • Substance use • Alcohol abuse in pregnancy leading cause of mental retardation in US. Related to ^ developmental problems & fetal growth restriction. • Medications: OTC [caution; get MD advice 1st]