physiological and psychological changes during pregnancy

Chapter 4

Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 1

Determining Pregnancy and Physiological Changes


Profile of Previous Obstetric History

Mnemonic commonly used for recording Systematic, quick way to indicate the number

of pregnancies as well as outcomes. GTPALM

G: gravida T: term pregnancies P: premature births A: abortions L: live births M: multiple gestations and births


Profile of Previous Obstetric History (cont.)

G: gravida Any pregnancy, regardless of duration, including

the present one P: para

number of births after 20 weeks gestation

e.g.: woman pregnant for first time would be:P0, G1


Determining Date of Birth

EDD: estimated date of delivery Nägele’s rule:

Identify first day of last normal menstrual period (LNMP)

Count backward 3 months Add 7 days


Duration of Pregnancy

Calculated in 28-day month calendar, called lunar months

10 lunar months in a full-term pregnancy 40 weeks 280 days on average


Trimester

Pregnancy broken out into 3-month segments called trimesters First trimester: first 14 weeks Second trimester: 15 to 28 weeks Third trimester: 29 weeks to delivery


Pregnancy Terms

Terminates before fetus reaches 20 weeks gestation: abortion (lay term is miscarriage)

Terminates after 20th week but before full term is reached: preterm (premature) birth

Terminates 2 weeks after EDD, or 42 weeks: postterm birth


Signs of Pregnancy

Presumptive signs Suggest pregnancy

Probable signs Likely pregnant

Positive signs Definite evidence of pregnancy


Three Signs that Define Pregnancy

Hearing fetal heart sounds Audible by doppler 10-12 weeks

Palpation of active fetal movements Visualization of a developing fetus via

ultrasound Gestational sac can be viewed as early as 10 days

after implantation


Pregnancy Tests

Presence of the hormone human chorionic gonadotropin (hCG) Produced by the chorionic villi of the placenta Can be found in woman’s urine as early as 1 week

postconception PROBABLE indicator of pregnancy


Physiologic Changesin Body Systems


Major Sources of Change

Hormonal (endocrine system) Mechanical pressure (physical changes

within the body)


Changes in the Endocrine System

Dramatic hormonal increase affects all body systems

Essential to maintain pregnancy Initially produced by corpus luteum Later by placenta

A temporary endocrine organ Role is to produce high levels of estrogen and

progesterone


Human Placental Lactogen (hPL)

Increases maternal insulin resistance during pregnancy

Provides fetus with glucose needed for growth


Changes in the Reproductive System


Uterus

Enlarges during pregnancy Increase in size of preexisting muscle cells

(hypertrophy) Formation of new cells (hyperplasia)

Circulatory requirements increase as it enlarges

Growth stimulated by hormones Pressure of growing fetus against uterine wall


Cervix

Becomes shorter and softer during pregnancy Prepares for

Thinning (effacement) Enlargement (dilation)

Softening caused by Hormones leading to increased blood supply Increase in cervical gland secretions

• Mucous plug formation provides barrier to prevent organisms from entering uterus.


Ovaries

Follicles cease to develop to maturity Ovulation does not occur

Corpus luteum produces estrogen and progesterone for first 7 to 10 weeks until placenta can take over Also produces hormone relaxin

• Thought to help relax symphysis pubis and pelvic joint, and softens cervix


Vagina

Wall thickens, becomes more pliable, and expandable

Rugae (folds) more prominent Discharge increases, leads to increased

glycogen, which increases risk of vaginal infection Increased risk for infection and Candida albicans pH decreases (becomes more acidic), preventing

growth of harmful microbes


Breasts

Hormones prepare breasts for lactation Rapidly enlarge during first 8 weeks of

gestation Vascular engorgement

Beginning in 9th week Ductal growth stimulated by estrogen Alveolar hypertrophy stimulated by progesterone


Breast Changes Size increases

Become fuller, more sensitive, and tender Pigmentation of areola and nipple darkens Montgomery’s glands more prominent

Lubricate and protect nipples Striae may occur Colostrum excretion as early as 10th week

Thin, yellowish fluid excreted until 3rd post partum day


Initiation of Lactation

Profound drop in estrogen and progesterone After delivery of placenta

Increase in prolactin Responsible for milk production


Changes in the Cardiovascular System


Cardiovascular

Deliver oxygen and nutrients Blood must be at pressures sufficient to meet

placental circulation 10% of maternal output channeled to uterine blood

flow in third trimester Greatest increase occurs during labor and

delivery More vulnerable to thrombus formation


Supine Hypotensive Syndrome


Changes in Respiratory System Thoracic circumference increases

Hormonal influence Lung capacity remains the same Inspiration increases

Allows greater intake of oxygen Expiration increases

Allows greater removal of carbon dioxide Breathing changes from abdominal to

thoracic Oxygen consumption increased by 15-40%


Dyspnea

Respiratory system has increased sensitivity due to progesterone

Pressure of uterus on diaphragm Normally does not interfere with activities of

daily living


Epistaxis

Nosebleeds and nasal stuffiness common Likely from increased vascularity related to

estrogen Voice may become deeper

Vocal cords increase in size, likely due to progesterone


Changes in the GI System Gum hypertrophy Saliva production increased (ptyalism) Nausea and/or vomiting, especially in first

trimester Constipation

Due to increase in progesterone and relaxin Pyrosis (heartburn)

Relaxation of cardiac sphincter from progesterone Carbohydrate metabolism altered

Increased insulin resistance can cause gestational DM


Compression of Abdominal Contents


Changes in the Renal System

Early and late pregnancy increase in bladder pressure

Ureters dilate from smooth muscle relaxation Increased risk of pyelonephritis if woman has

asymptomatic bacteriuria


Fluid and Electrolyte Balance

Increased glomerular filtration rate Increased sodium filtration (up to 50%) Tubular reabsorption (up to 99% reabsorption

of sodium) Increases risk of sodium retention Blood more alkaline

Enhanced by hyperventilation during labor Does not interfere with pregnancy


Changes in the Integumentaryand Skeletal Systems

Relaxin and placental progesterone Relaxation and softening of pelvic joints

Widening of symphysis pubis “waddling gate”

Facilitates delivery of fetus Center of gravity shifts forward as uterus

enlarges Progressive lordosis

May experience difficulty with balance


Lordosis

Lordosis


Changes in the Skeletal System

Uterus stretches round ligaments Woman may develop diastasis recti

abdominis Separation of rectum abdominis muscles

Increased risk of carpal tunnel syndrome Due to weight gain and edema


Changes in the Integumentary System

Chloasma (“mask of pregnancy”)

Linea nigra (dark line on abdomen)

Striae gravidarum (stretch marks)


Effect of Pregnancy and Lactation on Medication Ingestion Subtherapeutic levels may occur due to

increased Plasma volume Cardiac output Glomerular filtration

Decreased gastric emptying Changes absorption and can delay onset of action


Effect of Pregnancyon Medication Ingestion

Parenteral medications may absorb more rapidly due to Increased blood flow Faster onset of action

Increased levels of estrogen and progesterone may alter hepatic function Results in increased drug accumulation

Some drugs can cross placenta


Effect of Lactation and Medications

Some drugs pass into breast milk If lactating, mother must take medication

immediately after infant breastfeeds


Psychological ChangesDuring Pregnancy

Body image changes Emotional security Cultural expectations Support from partner Whether pregnancy is unexpected Financial situations


Psychological ChangesDuring Pregnancy (cont.)

Major factors that influence the psychological impact of pregnancy A woman’s level of maturity Readiness for childbearing

Hormones contribute to mood swings


Body Image

Considered from four aspects Appearance

• May be difficult and occurs quickly Function

• Difficult if associated with loss of control (urinary incontinence)

Sensation• More sensitive to touch due to increased vasocongestion

Mobility


Responses to Pregnancy


Developmental Tasks Relate to sequence of trimesters; more

apparent in some than others Pregnancy validation

Focus is nurturing and protecting fetus May question identity as woman and mother

Fetal embodiment Incorporates fetus into body image; deals with

repressed thought and matures Fetal distinction (when quickening occurs)

Sees fetus as individual Role transition

Makes concrete plans for baby 45

Pregnant Women May Experience

Emotional lability Heightened sensitivity Increased need for affection Greater irritability Fear Anxiety

Needs to receive rather than give emotional support

Provide guidance and support


physiological and psychological changes during pregnancy

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