Chapter 11 Maternal Adaptation During Nursing Flashcards
Pregnancy
A dynamic & precisely coordinated process involving systemic & local changes in the mother that support the supply of oxygen & nutrients to the growing fetus in utero & in subsequent lactation
Lasts ~280 days (40 weeks)
Key Fertilization Basics
Fertilization usually occurs in the outer third of the fallopian tube (ampulla)
Ovum is receptive to fertilization for 24-48 hours after release from ovary
Sperm are viable for 24-72 hours after ejaculation
Once a sperm has penetrated the ovum, further sperm penetration is prohibited
Zygote: Fertilized ovum will begin cell division
Between 6-10 days the blastocyst will implant to the endometrium
Gestation
The length of time between conception and birth during which a fertilized ovum matures and grows in the female’s uterus
Gestational Age
Age of the pregnancy from the last normal menstrual period (LMP)
- Most references to pregnancy are usually in gestational age rather than fetal age
Fetal Age
Actual age of the growing baby
Factors that Determine the Success of Pregnancy
1) Fertilization & successful implantation of the developing embryo into the endometrium
2) Development & function of the placenta
3) Adaptation of the maternal physiology to accept the fetal allograft & satisfy its nutritional, metabolic, & physical demands
4) Appropriate growth and functional development of organs & homeostatic systems in the fetus
5) Proper timing of the birth so the fetus is mature enough to survive outside of the uterus
What is a pregnancy divided into?
Trimesters
How long does each trimester last?
Each trimester lasts 13 weeks
W/in each trimester, numerous adaptations take place that facilitate the growth of the fetus
What types of groups have the signs/symptoms of pregnancy been arranged into?
Presumptive, probable, & positive
Presumptive (Subjective) Signs
Signs that the mother can perceive
Most obvious presumptive sign: Absence of menstruation
- Skipping a period is not a reliable sign by itself; however, if it is accompanied w/ consistent nausea, fatigue, breast tenderness, & urinary frequency it may be likely
LEAST reliable indicators of pregnancy
- Any one of them can be caused by something other than pregnancy
Ex) Amenorrhea can also be caused by early menopause, endocrine dysfunction, malnutrition,..
Probable (Objective) Signs
Signs of pregnancy that can be detected on physical examination by a health care provider
Common probable signs include:
- Hegar Sign: Softening of the lower uterine segment or isthmus
- Goodell Sign: Softening of the cervix
- Chadwick Sign: Bluish-purple coloration of the vaginal mucosa & cervix
Other probable signs include:
- Changes in size & shape of the uterus
- Abdominal enlargement
- Braxton Hicks contractions
- Ballottement: Provider pushes against the woman’s cervix & feels rebound from the fetus
Elevation of hCG corresponds to the morning sickness period of ~6-12 weeks of pregnancy
Although they are more reliable than presumptive signs, they are still NOT 100% ACCURATE!!!!
Pregnancy Tests
Also considered to be a probable sign of pregnancy
In-home testing became available in 1977
- Appealing to the general public due to convenience, cost, & confidentiality
Vary in sensitivity, specificity, & accuracy
Influenced by length of gestation, specimen concentration, presence of blood, & presence of some drugs
- Human chorionic gonadotropin (hCG) is detectable in a serum of ~5% of clients 8 days after conception & in more than 98% of of clients by day 11
Most claim 99% accuracy (misleading-> has no bearing on the ability of at-home pregnancy tests to detect early pregnancy)
Human Chorionic Gonadotropin (hCG)
Glycoprotein & earliest biochemical marker of pregnancy
hCG level < 5 mIU/mL: Negative
Any hCG level > 25 mIU/mL: Positive
hCG levels in normal pregnancy usually double every 48 -72hrs until they peak ~60-70 days after fertilization
- At this point, they decrease to a plateau at 100-130 days of pregnancy
hCG doubling time is used as a marker by clinicians to differentiate normal from abnormal gestations
- Low levels are associated w/ ectopic pregnancies
- Higher than normal levels may indicate molar pregnancy or multiple-gestational pregnancies
Positive Signs
Confirm that a fetus is growing in the uterus
Include:
- Visualizing a fetus via ultrasound
- Palpating for fetal movements
- Hearing a fetal heartbeat
* All signs that make pregnancy a certainty*
If a pregnancy test is (+), a clinical visit SHOULD include an estimation of gestational age so, appropriate counseling can be given
- Should also receive info on normal signs & symptoms of early pregnancy
- Instructed to report any concerns to the provider for further evaluation
- Prenatal visits will be set-up throughout the duration of the pregnancy
What are the only signs that can determine a pregnancy w/ 100% accuracy?
Positive signs
What does the elevation of hCG correspond to?
Morning sickness period of ~6–12 weeks of pregnancy
Reproductive Adaptations During Pregnancy: Uterus
Decrease in uterine vascular and muscle tone
Grows at a steady & predictable rate during pregnancy
- Uterus is normally pear-shaped, the uterus will expand more in length than width-> globe shape
-> Exits the pelvis by 12 weeks gestation
-> Walls thin to 1.5 cm or less
Estrogen stimulates uterine growth-> increases in size, weight, length, width, depth, volume, & overall capacity
- Weight: Increases from 70g to ~1,100-1,200g at term
- Capacity: Increases from 10-5,000 mL or more at term
Uterine growth occurs as a result of both hyperplasia & hypertrophy of myometrium cells (increase in size)
- Major component of myometrial growth occurs after mid-gestation due to smooth muscle hypertrophy via mechanical switch from the fetus
Reproductive Adaptations During Pregnancy: Uterine Blood Flow
Increase in blood flow -> blood vessels elongate, enlarge, dilate & sprout new branches to support and nourish growing tissue
As pregnancy progresses, 80-90% of blood flow is directed to the placenta & remainder is distributed between the endometrium & myometrium
Diameter of the main uterine artery ~2X in size
- Enlargement from a narrow to large-caliber vessel enhances the capacity of the uteroplacental vessels to accommodate the increased blood volume needed to supply the placents
Reproductive Adaptations During Pregnancy: Uterine Contractility
Uterine contractility is enhanced as well
Braxton-Hicks begin during the 1st trimester of pregnancy
- Continue throughout the pregnancy and become more noticeable during the last month
- Function: To thin out or efface the cervix before birth
Braxton-Hicks
Spontaneous, irregular, & painless contractions
Begin during the 1st trimester
- Continue throughout pregnancy, become more noticeable during last month-> Thin out or efface the cervix
Reproductive Adaptations During Pregnancy: The Impact of Uterine Changes on the Bladder
Lower portion of the uterus (isthmus) does NOT undergo hypertrophy & becomes increasingly thinner as pregnancy progresses-> forms the lower uterine segment
- Occur during the first 6-8 weeks gestation-> produces most of of the signs (includes Hegar’s sign)
Softening & compressibility of the lower uterine segments results in exaggerated uterine anteflexion during early months of pregnancy
- Adds to urinary frequency by placing pressure on the bladder
Uterus remains in the pelvis in the 1st 3 months of pregnancy, then ascends into the abdomen
- As uterus grows, puts pressure on the bladder
Reproductive Adaptations During Pregnancy: Uterine Ascension
Uterus remains in pelvic cavity for the 1st 3 months of pregnancy-> progressively ascends into the abdomen
The heavy gravid uterus in the last trimester can fall back on the inferior vena cava in supine position
- Causes vena cava compression-> reduces venous pressure, CO, & BP, increases orthostatic stress
-> May experience lightheadedness when changing position from sitting to standing
Hypotensive Syndrome
- These changes may be reversed in the side-lying position: displaces the uterus to the left and off the vena cava
- Do not lay on the back!!! (Side-lying or w/pillow)
Hypotensive Syndrome
Causes a woman to experience symptoms of weakness, lightheadedness, nausea, dizziness, or syncope
(T/F) True or False: It is fine for a pregnant mother to lie in supine position.
FALSE!!
This can cause further compression on the inferior vena cava-> cutting off blood flow
Reproductive Adaptations During Pregnancy: Fundus
Uterus becomes ovoid as length increases over width
By 20 weeks, fundus is at the level of the umbilicus & measures 20 cm
Can usually be correlated w/ gestational weeks, most accurately between 8-12 weeks
- Obesity, hydramnios, & uterine fibroids interfere w/accuracy
Reaches the highest level at xiphoid process around the 36-week mark
- Breathing becomes difficult since its pushing against the diaphragm
Between 38-40 weeks, the fundal height drops as baby begins to descend & engage into the pelvis
- Breathing becomes easier from descent
- Pressure on the bladder increases-> urinary frequency
Fundus
The top of the uterus
Lightening
The fetal head begins to descend & engage into the pelvis
Occurs by the 40 week mark
- In women w/1st pregnancy, occurs ~2 weeks before onset of labor
- In women w/ subsequent pregnancy, occurs at the onset of labor
Reproductive Adaptations During Pregnancy: Cervix
Between weeks 6-8, cervix begins to soften due to vasocongestion & influence of estrogen (Goodell’s sign)
Endocervical glands increase in size & number & produces more cervical mucus
Under progesterone influence: Thick mucus plug is formed & blocks the cervical os & protects opening from bacterial invasion
Increased vascularization occurs at the same time-> bluish-purple coloration of the cervix (Chadwick’s sign)
Cervical ripening occurs ~4 weeks before birth
Connective tissue change elasticity & strength to prep for birth
Cervical Ripening
Softening, effacement, & increased distensibility
Cervical Effacement
The thinning & shortening of the cervix
Reproductive Adaptations During Pregnancy: Vagina
Vascularity increases due to estrogen-> pelvic congestion & vaginal hypertrophy
- Prep for distentsion needed for birth
Vaginal mucosa thickens, connective tissue begins to loosen, smooth muscle begins to hypertrophy & vaginal vault begins to lengthen
Secretions tend to become more acidic, white, & thick
Leukorrhea: Increase in vaginal whitish discharge
- Normal, except when accompanied w/itching-> Candida albicans (monilial vaginitis)
- Can be passed from mother-> baby (oral thrush)
-> White patches on mucous membranes of mouth
Treatment: Local antifungal agents