Module 4: The Physiology of Pregnancy Flashcards
(145 cards)
1
Q
Gestational age
A
-calculated from the first day of a woman’s last menstrual period
-refers to the age of pregnancy
2
Q
Fetal age
A
-estimated from date of conception
-must be approximately 2 weeks less than gestational age
3
Q
How long is average human pregnancy
A
-38-40 weeks
4
Q
First trimester time period
A
-from week of conception to 13th week of gestation
5
Q
First trimester development
A
-organ systems
-mothers body increases blood supply to carry more nutrients and oxygen
6
Q
First trimester symptoms
A
-fatigue
-morning sickness
-headaches
-constipation
7
Q
Second trimester time period
A
-week 13 to 26 of gestation
8
Q
Second trimester development
A
-hair nails and reproductive organs develop
-sex of fetus can be determined
-fetus begins to make movements
9
Q
Second trimester symptoms
A
-body aches
-dizziness
-swelling of hands and feet
10
Q
Third trimester time period
A
-from week 27 to birth of baby
11
Q
Third trimester development
A
-fetus gains weight
-organ systems mature
12
Q
When does birth usually occur
A
-from week 37-42
13
Q
Possible positions of baby
A
-cephalic
-breech
14
Q
Cephalic position
A
-head down
15
Q
Breech position
A
-bottom down
16
Q
When is the fetus most vulnerable
A
-weeks 3-10
17
Q
Teratogens
A
-agents that have the ability to cause birth defects such as radiation, alcohol, and certain prescriptions
18
Q
When are miscarriages most common
A
-first trimester
19
Q
Preterm delivery
A
-birth before 37 weeks
20
Q
Preterm delivery complications
A
-maternal complications
-worsening health outcomes for baby
21
Q
Full term delivery
A
-37-40 weeks
22
Q
Late term delivery
A
-in week 41
23
Q
Post term delivery
A
-beyond 42 weeks
24
Q
Post term delivery complications
A
-significant risk
25
Postnatal period
-6 week period immediately after pregnancy in which mother undergoes significant physical and psychological changes
26
Naegeles rule
-standard way of calculating delivery date for pregnancy
27
Naegeles rule 3 steps
-determine when the first day of your last menstrual period was
-count back 3 calendar months from date
-add 1 year and 7 days to that date
28
Embryonic stage
-comprises the first 8 weeks of development
-called an embryo
-major morphological stages
29
Fetal stage
-begins after week 8
-called a fetus
-growth and development
30
How many carnagie stages are there
-23
31
Weeks 0-2
-called a zygote
-carnegie stages 1-6
-undergoes cleavage and develops germ layers
32
Weeks 3-4
-called an embryo
-carnegie stages 7-13
-germ layers begin to differentiate
-primordial germ cells form wolffian and mullerian ducts
-primitive heart develops
33
Week 5
-called an embryo
-canegie stages 14-15
-chambers of heart become visible
-limb budding
-cerebral hemispheres become visible
34
Week 6
-called an embryo
-carnegie stages 16-17
-heart and lungs descend into thorax
-heart beats at normal rhythm
35
Weeks 7-8
-called a fetus
-carnegie stages 18-23
-fingers become visible
-bone ossification
-testes begin descent
36
What size is fetus at week 8
-kumquat
37
What size is fetus at 11 weeks
-lemon
38
What size is fetus at 14 weeks
-avocado
39
What size is fetus at 21 weeks
-grapefruit
40
What size is fetus at 29 weeks
-coconut
41
What size is fetus at 38 weeks
-watermelon
42
What does ultrasound tell us
-confirm pregnancy and location
-evaluate placenta and fluid levels
-confirm number of babies
-identify birth defects
-determine gestational age
-determine fetal position
-evaluate fetal growth
43
Types of placental invasiveness
-epitheliochorial
-endotheliochorial
-hemochorial
44
Epitheliochorial
-least invasive
-maternal blood is seperate from fetal tissues by endothelium, connective tissue and epithelium
45
What organisms have epitheliochorial invasiveness
-cows
-pigs
-horses
46
Endotheliochorial
-maternal blood is separated by layer of maternal endothelium and some interstitial tissue
47
What organisms have endotheliochorial invasiveness
-dogs
-cats
48
Hemochorial
-human placenta allows fetal membranes to be bathed directly with maternal blood
49
What organisms have hemochorial invasiveness
-humans
-mice
-rabbits
50
Primary functions of placenta
-nutrient and oxygen exchange
-protection
-hormone production
-excretion
-attachment to uterine wall
51
Layers of trophoblast
-synctiotrophoblast
-cytotrophoblast
52
Syncytiotrophoblast composition
-cytotrophoblast cells that fuse together into a multinucleated continuous cell later known as syncytium
53
What does syncytiotrophoblast layer go on to form
-blood-placental barrier
54
Blood placental barrier function
-help regulate nutrient/gas exchange
-production of placental hormones
-regulating immune response
55
Cytotrophoblast composition
-comprise inner layer of trophoblast cells
-produce proteolytic enzymes to facilitate invasion of decidua
56
Cytotrophoblast cells function
-replensih cells of outer syncytium layer
57
What are chorionic villi
-finger-like projections from cytotrophoblast layer
58
Primary villus
-small and avascular
-cytotrophoblast core surrounded by a layer of syncytium
59
Secondary villus
-composed of extraembryonic mesodermal core and are covered by layer of cytotrophoblast cells and outer syncytiotrophoblast layer
60
Tertiary villus
-have extraembryonic mesoderm core with villous capillaries and are covered by a cytotrophoblastic and suncytiotrophoblastic layer
61
Anchoring villi
-large tertiary villi that connect cytotrophoblastic shell to chorionic plate
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Floating villi
-branches of anchoring villi
63
Intervillous space
-space between villi, between chorionic shell and chorionic plate
-this is where maternal circulation will pool and bathe chorionic villi
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Chorion
-shell and chorionic plate together surround embryo to form this
65
Chorion frondosome
-highly villous area
-fetal side of placenta
66
Chorion laeve
-any villi on opposite side will atrophy
67
Decidua basalis
-side of decidua where chorion frondosome attaches and grows
68
Decidua capsularis
-other side of decidua surrounding embryo
-does not interact with chorionic cilli and will later become a smooth layer
69
Amnion
-innermost fetal membrane
-contains amniotic fluid
-protects embryo from mechanical stress and impact
70
Yolk sac
-small sac on ventral surfce of embryo
-source of primordial germ cells and blood cells
71
Allantois
-hollow sac on tail end of yolk sac
-contributes to nutrition and excretion
-helps form umbilical cord
72
Chorion
-outermost fetal membrane
-forms the fetal side of placenta (chorion frondosome and laeve)
73
Extraembryonic coelom
-space between amnion and chorion
74
Spiral artery remodelling
-blood vessels that supply uterus are characterized as having spiral shape
-also the same arteries that will supply placenta and growing fetus
-extravillous trophoblasts will migrate towards maternal arteries and cause major modifications of their walls
75
Extravillous trophoblasts
-highly invasive type of cytotrophoblast arising from tips of anchoring villi
76
Spiral artery remodelling in early pregnancy
-extravillous trophoblasts proliferate from anchoring villi and invade maternal decidua
77
Spiral artery remodelling end of first trimester
-extravillous trophoblasts differentiate into 2 types
-interstitial and endovascular
78
Interstitial extravillous trophoblasts
-these cells invade deeper into decidua and surround spiral arteries
79
Endovascular extravillous trophoblasts
-penetrate the lumen of the uterine spiral arteries
80
Spiral artery remodelling midgestational period
-both types of extravillous trophoblasts are involved in degradation of maternal vascular endothelium
-as a result the spiral arteries become wider, allowing higher volume of blood
81
Spiral artery remodelling 3rd trimester
-blood supply to uterus and placenta has increased by a factor of 10 as a result of the remodelling
82
Types of placental circulation
-uteroplacental circulation
-fetoplacental circulation
83
Uteroplacental circulation
-maternal blood flows from uterine space into intervillous space, allowing for exchange of oxygen
84
Fetoplacental circulation
-fetus attached to placenta directly via umbilical cord
-this allows transport to and from mothers blood without direct mixing
85
What does the umbilical cord have inside
-one umbilical vein
-two umbilical arteries
86
Umbilical vein function
-carries oxygenated, nutrient rich blood from placenta to fetus
87
Umbilical arteries function
-carries deoxygenated, nutrient-depleted blood from the fetus to the placenta
88
Functions of placenta as an immune barrier
-prevent maternal immune rejection
-protect fetus from pathogens
89
Preventing maternal immune rejection
-the fetus is genetically different than the mother so the barrier maintains separation between maternal and fetal blood to prevent the mothers immune cells from recognizing fetal tissues as a foreign body
90
How do pregnancy tests work
-measure the hCG hormone levels in urine
91
When are pregnancy tests most accurate
-when taken after the first missed menstrual cycle
92
Sex hormones during trimester 1
-hCG must appear by day 10 in order to stop the corpus luteum from degrading
93
Sex hormones during trimester 2
-placenta starts producing enough progesterone and estrogen to sustain remainder of pregnancy
-production of hCG decreases and corpus luteum degrades
94
Sex hormones in trimester 3
-levels of progesterone and estrogen increase steadily due to production by placenta
-largely responsible for many physiological changes observed during pregnancy
95
Adrenal cortex changes during pregnancy
-adrenocorticotropic hormone (ACTH) is involved in stress response so it regulates functions such as appetite suppression and feelings of anxiety
96
Which hormone is responsible for timing of parturition
-ACTH
97
Thyroid gland changes during pregnancy
-thyroid hormone increases
-therefore increasing maternal metabolic rate to meet demands of fetus
98
Ovary changes during pregnancy
-FSH and LH are inhibited during pregnancy
-ovulation therefore does not happen
-can take 2 months to a year after birth to go back to normal
99
Mammary glands changes during pregnancy
-mainly stimulates mammary glands to produce milk
-PRL stimulates breasts to grow
100
Cervix changes during pregnancy
-softens
-necessary to permit variety of functions such as dilation during delivery etc
101
What is colostrum
-the first milk
-appears in alveoli of acinar glands as early as second trimester
102
Uterus changes during pregnancy
-endometrial layer goes through decidualization
-uterus is stretched to accomodate fetus etc
103
Circulatory system changes during pregnancy
-cardiac output increases by as much as 50% mid pregnancy
-happens as a result of increased heart rate and stroke volume
104
Respiratory system changes during pregnancy
-oxygen consumption increases by 20-60% during labour
-around month 6 the fetus begins to exert increasing pressure on mothers diaphragm decreasing lung capacity and increasing minute ventilation
105
Immune system changes during pregnancy
-immune response prevents rejection of paternal antigens but therefore makes women more susceptible to infectious diseases
106
Metabolic system changes during pregnancy
-in early pregnancy it is anabolic
-in late pregnancy is is catabolic
-insulin resistance develops in early pregnancy to direct most of glucose to fetus
-in late pregnancy, maternal adipose tissue releases fatty acids for use by liver and muscle
107
Parturition
-the process by which childbirth occurs
-labour and delivery
108
Stages of parturition
-onset of labour
-active labour
-delivery of placenta
-immediate postpartum
109
Onset of labour
-stage preceding labour
110
Phases of onset of labour
-latent phase
-active phase
111
Latent phase of onset of labour
-mother starts experiencing contractions until dilated to 3 cm
112
Active phase of onset of labour
-contractions become more intensive
113
Steps of onset of labour
1. response to fetal head on cervix causes stretching of cervix and uterine walls
2. in response to stretching, nerve impulses are sent to hypothalamus of brain
3. hypothalamus signals posterior pituitary to release oxytocin
4. oxytocin joins circulation and causes smooth muscle contractions of myometrium which increases cervical dilation
114
Onset of labour signs and symptoms
-lightening (baby moves down in pelvis and breathing may be easier)
-uterine contractions
-water breaks
115
Active labour
-cervix progressively dilates
-ferguson reflex
116
Ferguson reflex
-positive feedback cycle
-pressure on cervix releases oxytocin and dilates cervix etc
117
How long may active labour last
-8-20 hours
118
Delivery of placenta
-shortest stage
-starts immediately after fetal birth
-physician will put pressure on mothers abdomen to help detach placenta from uterus
119
How long may delivery of placenta take
--5-30 min
120
Signs of placental separation
-firmer uterine fundus
-sudden gush of blood from vagina
-lengthening of umbilical cord
-rise of uterus in abdomen
121
Immediate postpartum
-hour or 2 after delivery when tone of uterus is reestablished
-uterine massage often used
-colostrum from mammary glands will provide basic immunity for first few hours
122
What is the puerperium period
-postpartum up to 6 weeks after birth
123
Complications of parturition
-breech birth
124
Breech birth
-happens when baby is delivered bottom first
125
What can practitioner do about breech birth
-may change baby into appropriate position before birth
-may perform a c section
126
What will majority of pregnancy complications be attributed to
-some kind of disruption to placental function
127
First trimester complications
-generally associated with disruptions in process of implantation or early embryo development
128
Miscarriage
-loss of embryo before 20th week of gestation
-most often a natural response to presence of abnormality
129
Anembyonic pregnancy
-condition where embryo does not develop, leaving only gestational sac
130
Second trimester complications
-often result of issues that were initiated in first trimester
131
Who is at higher risk of second trimester complications
-women with preexisting conditions such as hypertension or diabetes
132
Preeclampsia
-most severe hypertensive disorder of pregnancy
-high blood pressure and excess protein in urine
133
What is the main danger of preeclampsia
-can evolve into eclampsia and cause seizures in mother
134
What is preeclampsia associated with
-impaired placentation
-uterine artery remodeling is impaired
135
Third trimester complications
-any health issues that arose in second trimester can become worsened and lead to ealy delivery
136
Antepartum hemorrhage
-bleeding that occurs after the 24th week of gestation but before birth
-medical emergency
137
Placental anatomy abnormalities
-abruprtio placenta
-placenta previa
138
Abruptio placenta
-premature separation of placenta from uterus
139
Placenta previa
-occurs when placenta is partially or totally covering mothers cervix, obstructing birth canal
140
How do fetal complications affect long term health
-intrauterine growth restriction
-preterm birth
141
Intrauterine growth restriction
-significant reduction in fetal growth
-typically result of placental insufficiency
-has been linked to poorer health outcomes in later adult life
142
Preterm birth
-leading cause of neonatal death
143
Effect of preterm birth on development and adult health
-preterm infants are exposed to various stressors and environmental conditions
-these stressors can lead to permanent changes in organ system development which may incerase risk of specific disorders
144
Potential explanations for preterm birth worldwide trends
-changing pregnancy demographics
-induced preterm births to improve fetal mortality rates
-reporting of medically induced preterm births
145
Maternal and fetal screening benefits
-advances in diagnostic and treatment procedures have decreased maternal and neonatal morbidity by increasing early detection of maternal and fetal problems
