normal pregnancy and prenatal care - obgy.womanschool.cn

Normal pregnancy and prenatal care

Li Xiao

5198008@zju.edu.cnWomen’s Hospital

Zhejiang University School of Medicine

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Part I

Normal Pregnancy

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Terminology/Nomenclature

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Fimbriated end

within 12-24h ofovulation, occursat the ampulla

Receptivity of uterus• Apposition• Adhesion• Penetration

wWhen does human life begin?n When an oocyte is fertilized by sperm

wWhat’s pregnancy?n The state of having products of conception

implanted in the uterus or elsewheren Terminated by abortion or delivery

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Terminology/Nomenclature

Terminology/Nomenclature

The duration of pregnancyw Fertilization age (FA): the age of the

offspring calculated from the time of fertilization w Gestational age(GA): It is calculated from

the first day of the last menstrual period (LMP, assuming a 28 day cycle) and expressed in completed age

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Gestational age in weeks

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Terminology/Nomenclature

w Embryo: 0-8 weeks FA (10w GA)w Fetus: 8-40 weeks FA

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Terminology/Nomenclature

w Gravidity: the total number of pregnancies (normal and abnormal)

w Parity: the numbers of having given birth to an infant ≥ 20weeks GA or infants weighing >500g, alive or dead. (A multiple birth is a single parous experience)

w Live birth: the complete expulsion or extraction of a product of conception from the mother, which shows evidence of life

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Terminology/Nomenclature

w Abortion: expulsion or extraction of all or any part of the placenta or membranes, without an identifiable fetus or with a fetus before 20W GA

w Infant: live-born individual from birth until the completion of 1 year of lifen Immature infant: weighs 500-1000g and has completed

20 weeks to less than 28 weeksn Premature infant: weighs 1000-2500g and has completed

28 weeks to less than 37 weeksn Mature infant: a live-born infant completed 37 weeks of

gestation and usually weighs >2500g9

Terminology/Nomenclature

w Preterm: before 37 weeks w Term: 37 to 42 weeksw Posterm: beyond 42 weeks

n Postmature infant: completed 42 weeks or more of gestation

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Terminology/Nomenclature

w Undergrown or small for date infant: significantly under sized for the period of gestation (<2SD)w Neonatal interval: from birth to 28 days of lifew Perinatal interval: the span of fetal and neonatal

life (I: 28W to first 7D of life, II: 20W to 27D of life)

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Pregnancy Diagnosis

w It may be crucial to diagnose pregnancy before the first missed menstrual period n to prevent exposure of the fetus to hazardous

substancesn to manage ectopic or nonviable pregnanciesn or to provide better health care for the mother

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Manifestations of pregnancy

w 3 groupsn presumptiven probablen positive

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Presumptive Symptoms

w Amenorrheaw Nausea with or without vomitingw Breast changew Urinary tractw Quickening w Fatigue

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Presumptive Symptoms

w Amenorrhea: strongly suggestive of pregnancy w Nausea and vomiting

n Morning sickness of pregnancyn Results from rapidly rising serum levels of

HCG (human chorionic gonadotropin)n Begin at 4 weeks and finish at 12 weeks

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Presumptive Symptoms

w Breast changesn Tenderness and tinglingn Enlargement (second month )n Nodularity (sebaceous glands)n Colostrums secretion (begin after 16 w

gestation)n Secondary breasts (Axillary breast tissue often

cause a symptomatic lump in the axilla)

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Secondary breast

Breast Enlargement

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Presumptive Symptomsw Urinary tract

n Frequent urination and nocturia n Infection

w Quickening n 16-20weeks in primigravidas n 14-16 weeks in multigravidas

w Fatigue n one of the earliest symptoms of pregnancyn returns to normal by the 16th to 18th week

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Presumptive signs

w Increased basal body temperature (>21 days)

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Linea nigra and stretch marks

Stretch marks

nLinea nigra: darkening of the nipples and lower midline of abdomen

nStretch marks: separation of the underling collagen tissue and appear as irregular scars

Skin changes

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Skin changes

w Chloasma:darkening of the skin over forehead, bridge of the nose and cheekbones

w Spider telangiectases

AFTER BEFORE

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Probable Symptoms

w Same as presumptive symptoms

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Probable Signs

w Pelvic organsn Leukorrhea: vaginal discharge increasedn Chadwick’s sign: vaginal mucosa and cervix become

bluish (6-8w)n Hegar’s sign: softening between cervix and uterine

fundus causes a sensation of separateness between these two structures(6-10w)

n Goodell’s sign: cyanosis and softening of cervix(4w)n Ladin sign: softening of the uterus after 6 wn Bones and ligaments of pelvis (relaxation)

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Probable Signs

w Abdominal enlargement(the uterus rises out of the

pelvis and into the abdomen)

w Uterine contractions (Braxton hicks contractions)

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wBallottement (16-20w)wUterine souffle

It may be more easily accomplished by a vaginal examination

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Pregnancy test

HCG is produced by trophoblast 8 days after fertilization w Urine pregnancy test

n Positive around the first missed cyclew Serum pregnancy test: more sensitive

n HCG may be detected in maternal serum at 9 days

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HCG changes during pregnancy

w A viable pregnancy can be confirmed by US at a HCG of 1500-2000IU/L(5w)w Fetal heart at 5000-6000IU/L(6w)w Rise to a peak of 100,000 IU/L at 10-12

weeks w Decrease throughout the second trimesterw Level off at 20000-30000IU/L in the third

trimester27

• Ultrasound examination of fetus is one of the most useful technical way

Positive manifestations

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20 weeks

36 weeks

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Positive manifestations

w Fetal heart tone (110-160 BPM)

Doppler device can detect at 10 weeks

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Positive manifestations

w Palpation of fetus (22 weeks)n Leopold

Maneuver to determine the fetal presentation

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X rays of fetus(replaced by ultrasound)

Positive manifestations

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Other physiology changes

w Endocrine：E、hCGw Cardiovascular

n Cardiac output 30-50%n Systemic vascular resistance (progesterone)

w Pulmonaryn Tidal volume 30-40%n Total lung capacity (elevation of the diaphragm)

w Hematology plasma 50% RBC 20-30% (dilutional anemia) WBC and platelet

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Estimated date of confinement (EDC)

w Mean duration of pregnancy is 280 daysw Nagele's rule

n Subtract 3 from (or add 9 to) the month of the last normal menstrual period, and add 7 to the first day of the last normal menstrual period

n Assumed 28 day cycle with ovulation on D14wUS may be used if the LMP is uncertain

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Example of EDC

w LMP: Feb 1st, 2009, 28 days cyclew EDC: Nov 8th, 2009 （2+9=11；1+7=8）w LMP: sep 1st, 2009, 40 days cyclew EDC: Jun 20th, 2010 （9-3=6；1+7=8,8+(40-28)=20）

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Three trimesters of Pregnancy

w A pregnancy is divided into three phases, called trimestersn First trimester: 0 until 12-14 weeks n Second trimester: 12-14 until 24-28 weeks n Third trimester: 24-28 until delivery

w Each trimester has its own significant milestone

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First trimester

wRoutine problemsn Nausean Fatiguen Breast tendernessn Frequent urinationn Constipation

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First trimester

w Bleedingn Spontaneous abortion (15-25%)

w Pelvic or lower abdominal pain and vaginal bleeding ----ectopic pregnancy

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Second trimester

w General well-being: the most comfortable time for a pregnant womanwRoutine problems

n Pain: stretching of pelvic structuresn Contraction (Braxton hicks contractions)n Dehydrationn Edema: feet and ankles

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Second trimester

wBleeding: suggestive low lying placentaw Fetus: attains a size of almost 1000g by

28wn Motion: begin at 16-20wn Viability: at the end of this trimester, lung

immaturity will cause respiratory distress

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w Symptomsn Contraction: more apparentn Pain in the lower back and legs: pressure

on muscles and nerves by the uterus and fetal head

n Lightening: descent of the fetal head

Third trimester

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Third trimester

w Fetus n Weight: 3300g at termn Motion: decrease (lack of room within uterus)

wBleedingn Bloody show: approach of laborn Heavy bleeding: placenta previa or abruptio

placenta

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Third trimester

w Rupture of membranesn At term, labor begins within 24 h after rupturen Induction of labor is indicated if no labor within

24h after rupture or if there is any evidence of infection

w Laborn Contractions occur at decreasing intervals with

increasing intensity cause the progressive dilation and effacement of the cervix

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Prenatal care

Part II

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Terminology/Nomenclature

w Gravidaw Nulligravidaw Parityw Nulliparousw PrimiparawMultipara

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Standard nomenclature of pregnancies

G_P_, G_P_ _ _ _n G_: Gravidity, total number of pregnancies

including the current pregnancyn P_: Parity, total number of deliveriesn P_ _ _ _: Referred to the TPAL system, the first

number represents the Total number of full-term deliveries, the second is Preterm deliveries at 20 weeks or greater, the third number is Abortion, the fourth number is the number of Living children

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Prenatal care

w Preconception care n Women who consider pregnancy in 1-2 years

should be evaluated for the conditions that could affect a future pregnancy

w Routine prenatal caren Screen for various complications of pregnancy

and educate the patientn Include a series of outpatient office visits

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Routine prenatal care

w Initial prenatal visit: 6-10w suggested

w Follow-up prenatal care n First trimester visitn Second trimester visit n Third trimester visit

w Prepare for labor

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Initial Visit

wUsually in the first trimester, most thorough, longestn History n Physical examination n Laboratory tests

wEducaiton:n Diet, exercise and weight gain (20-30ib)

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History

w Present history (LMP, symptoms)w Obstetrical history w Medical history w Family historyw Social history

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Complete obstetric history

w Present pregnancy and menstrual historyn Estimated gestational age(EGA), EDCn The length and duration of menstruation

w Previous pregnancies n EGA at the time of delivery or abortionn Fetal outcomen Mode of delivery: vaginal or cesarean sectionn Complications: GDM, preeclampsia, PPROM

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Medical history

w Previous and current medical diseasen Diabetes, chronic hypertensionn Medication n Previous surgeriesn Blood transfusion history

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General history

w Family historyn Diabetesn Mental retardationn Genetic disorders

w Social history and education

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Physical examination

wGeneral examination n Height, weight and blood pressure should

be recordedn Systolic flow murmur at the left sternal

border

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Physical examination

w Pelvic examination n Evaluation for abnormal vaginal dischargen Performance of cervical culture n Pap smearn Assessment of pelvic soft tissue: cervix and uterinen Bony pelvis (Clinical pelvimetry)

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Laboratory Tests

w Blood screening n Blood routine testn Blood type (ABO and RH)n Detect diseases: rubella, syphilis, hepatitis B, HIVn Screening test for certain diseases according family

historyw Urinalysis

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Laboratory tests

w Stool test when indicatedw Tuberculin skin test for high risk patientsw Infectious disease: gonorrhea, chlamydia,

group B streptococcus(35-37w), et alw First trimester screening (11w-13w6d)

n Nuchal translucency(NT) measurementn serum analytes: hCG +pappa

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Subsequent Visit

w Every 4w until 28ww Every 2w until 36ww After 36 weeks, every 1 w until deliveryw Complicated pregnancies require closer

surveillance

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Subsequent Visit

w The symptoms of pregnancy should be asked w Weight gainw Blood pressurew Fundal heightw Abdominal examinationw Fetal heart tonesw Edema w Urine testw Repeat vaginal cluture for infectious dieases if needed

fetal size and position

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Symptoms indicate complications

w Vaginal bleeding w Vaginal dischargew Leaking of fluid w Urinary symptomsw Contractions w Fetal movement

20w

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Milestones

w Fetal movementn After 20 weeks, patients should be instructed to do

fetal kick counts, 10 fetal movements in 2 hoursw By 20 weeks: complete second trimester screening(15-

18w)l Serum analyses (genetic screening) :

AFP+HCG+Estriol+/-inhibinAl Screening ultrasound for fetal anatomic evaluation

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Milestones

w Between 24 and 28 weeks:n Third-trimester tests: CBC, RPR/VDRL, and

screening for GDM (GLT) n GTT: a diagnostic test for GDM

w 35-36 weeks: determine fetal presentationw After 41 weeks: Nonstress test twice weekly

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PART III

Methods of assessment for pregnancy at risk

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Terminology

w High-risk pregnancy One in which the mother, fetus or newborn is

at or may be at increased risk of morbidity or mortality before, during or after delivery. The likelihood of an adverse outcome is greater than in the general pregnancy population

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Terminology

wMaternal deathn Death occurs either during pregnancy or

within 42 days of the termination of pregnancyw Perinatal mortality

n The combination of fetal deaths and neonatal deaths per 1000 live birth

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Methods of assessment for pregnancy at risk

w Preconceptional evaluation and counselingwMaternal assessment for potential fetal

or perinatal risk w Fetal assessment

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Maternal assessment

w Initial screening (complete history and PE)w Antepartum course (Uniform perinatal record )w Screening test

n First and second trimester evaluation of risk for aneuploidy

n Blood screening testn Isoimmunization: RH or ABO incompatibility

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Fetal assessment

w Assessment of prenatal diagnosis n Ultrasound (fetal number, presentation, viability,

placental location, gestational age and fetal anatomy, multiple sonographic markers for aneuploidy screening) (18-20w)

n Amniocentesis (15-20w)n Chorionic villus sampling(9-12w)n Fetal blood sampling (higher risk)

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Assessment of fetal well-being

w Test of fetal heart rate n External fetal monitoringn Internal fetal monitoring

w Sonographic fetal monitoring(Biophysical profile and Doppler velocimetry)

w Lung marturiy

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Fetal heart rate tracing

wBaseline Raten Normal: 110~160 bpmn � Affected by following factors:

Gestational age Fetal status Maternal fever \ position \ drugs

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Periodic changes of FHR

w�Accelerationsw�Decelerations

Early Late Variable

w�Sinusoidal patterns

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Nonstress test (NST)

w Beginning at 32-34week of gestationw The criteria of reassuring(reactive) NST

n Baseline between 110-160bpm n Periodic acceleration of fetal heart rate of 15

bpm over baseline for 15 seconds (2 in 20min, reactive/reassuring)

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Biophysical profile (BPP)

w High risk pregnancy in third trimester or nonreactive NSTn NSTn Fetal breathing movementsn Fetal movementn Fetal tonen Determination of the amniotic fluid volume

A BPP of 8-10 or better is reassuring80

Oxytocin challenge test (OCT)

w Contraction stress test（CST）w 3 contractions occur in 10 min by intravenous

infusion of oxytocin or during laborw Further test for nonreassuring NST/BPP or in

more severe cases

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Fetal maturity tests

w Lung maturity is essential for normal respiration immediately after birthw Indications for assessing fetal lung maturity

n Before elective delivery at less than 39 week’s gestation unless fetal maturity can be inferred from any of these criterial Fetal heart tones documented for 30 weeks by Doppler or

for 20w by nonelectronic fetoscopel 36 weeks since a positive pregnancy test

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w Methods: measuring surface-active lipid components of surfactant(lecithin, phosphatidyl glycerol) in amniotic fluid obtained by amniocentesisn Lecithin: Sphingomyelin (L: S) Ratio >2n Phosphatidylglycerol (PG) >=0.3n Foam stability index (FSI) n Fluorescence polarization

Fetal maturity tests

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Intrapartum fetal surveillance

w Fetal heart rate assessment is the initial choicen Continuous fetal monitoring n Intermittent auscultation

w Ancillary tests n Fetal scalp blood samplingn Fetal lactate levels n Fetal pulse oximetry

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PART IV

Prenatal Screening, Diagnosis and Treatment

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Introduction

w A relatively new field within obstetricsn Related to the advent and advancement of

realtime USn Screening: select high-risk individuals for a

given diagnosis or complicationn Diagnosis: diagnostic and usually far more

specific than screening, but bear a greater risk of complications (Amniocentesis and CVS)

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Screening for genetic diseases

w The diseases are passed genetically from parents to their offspingn Autosomal dominant or recessive diseasen X-linked disorder

w The first step in determining fetal risk is to screen the mother for the diseasewWhich is usually done in high risk groups

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Common genetic diseases

w Autosomal dominant or recessive diseasen Cystic fibrosis 囊性纤维变性 (AR)n Sickle-cell disease 镰状细胞(贫血)病(AR)n Tay-Sachs disease (AR)n Thalassemia [θælə'si:miə]地中海贫血

w X-linked disordersn Hemophilia 血友病

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Chromosomal abnormalities

w Aneuploidy (extra or missing chromosomes)n Generally the cause of some syndromesn Obvious phenotypic differences and congenital

anomalies, not always be detected by prenatal USw Fetal karyotype is the only way to achieve a

definitive diagnosis of aneuploidyw Screening test are exist for some syndromes

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Chromosomal abnormalities

wTrisomy usually results in early abortionwAn infant is occasionally born with trisomy

and surviven Down syndrome(Trisomy 21)n Trisomy 18n Trisomy 13

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Sex chromosomal abnormalities

wMost common sex chromosome aneuploidesn 45XO: turner syndrome, monosomy Xn 47XXY: klinefelter syndrome

w The most common aneuploidies are those of sex chromosomes. They are less severely affected than the autosomal aneuploidiesw No screening test for these two syndormesw Diagnosed by prenatal diagnose

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Fetal congenital anomalies

w Primarily arise during embryogenesis, but also can progress as development continuesw Occur in any organ system

n Neural tube Defects: spina bifida and anencephalyAssociated with folate deficiency and can be screenedn Cardiac Defectsn Potter Syndrome (肾衰竭、羊水过少）

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Prenatal screening

w First trimester (11w-13w6d)n US: Nuchal translucency (NT) n Serum screen: HCG+PAPP-A

w Second trimester (15-20w)n Triple screen: MSAFP, estriol andβ-hCG

n Quad screen: MSAFP, estriol, β-hCG and inhibinA

n Realtime US

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Prenatal diagnosis

w Indications n Known carriers of a genetic disordern At high risk of aneuploidy based on age/historyn Positive screening test

w Involves obtaining fetal cells to perform a karyotype and possibly DNA test

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Prenatal diagnosis

w Amniocentesisn Be performed

beyond 15 weeks n Risk (1/200): rupture

of membranes, preterm labor and rarely fetal injury

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wChorionic villus sampling (9-12w)n Risk is higher:

preterm labor, premature rupture of membrane, previable labor, fetal injury

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Prenatal diagnosis

Prenatal diagnosis

w Fetal blood samplingn Performed by

placing a needle transabdominally into the uterus and phlebotomizing the cord

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Prenatal diagnosis

anencephaly

wFetal imagingnUltrasound: most commonly

nFetal echocardiogram: cardiac anomaly

nMRI

n3D US: The image more like the actual fetus

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Question 1

A 27 years old woman, gravida 1, para 1, presents for her first prenatal visit after testing positive on a home pregnancy test. She reports regular cycles every 35 days. She denies use of birth control pills or other contraceptive in the last 7 months. The first day of her last menstrual period was April 1, 2009, the last day was April 5, 2009. She says her periods always last 4-5 days. What is the best estimate of her due date?

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Question 2

A pregnant woman presents to your office for prenatal care. She has had two abortions, two second trimester miscarriages(15 and 13w), a fetal demise at 37 week s’ gestation, and two live births. Her son, who is now 13 years old, was delivered at 34 weeks’ gestation by spontaneous vaginal delivery. Her daughter , who is now 10 years old, was delivered at 38 weeks by cesarean section secondary to fetal distress during labor. What are her “Gs and Ps” by simple notation and by TPAL notation?

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Answers

w January 15, 2010

w G8P3, G8P2142

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