Module Two & Three Flashcards
Intrauterine Environment
Placenta, Umbilical Cord, Fetal membranes, Amniotic Fluid
Placenta: Structurally Complete by:
12th week
Placenta: Functions:
Supplies O2, Nutrients, Removes CO2 & Wastes
Placenta: Hormones:
Maintain Pregnancy, Facilitate Fetal Development, Prepare woman’s body for birth and lactation
Placenta: Layers
Maternal: Decidua Basalis
Fetal: Chorionic Sac
Two Protein Hormones produced by Placenta
1) Human Chorionic Gonadotropin
2) Human Chorionic Somatomammotropin
Two Steroidal Hormones produced by Placenta
1) Estrogen
2) Progesterone
Human Chorionic Basalis
Preserves function of corpus luteum, ensuring continued supply of estrogen and progesterone to maintain pregnancy
Human Chorionic Somatomammotropin
Stimulates fat metabolism to supply nutrients for fetal growth, increases maternal resistance to insulin, facilitates glucose transport across the placenta and stimulates breast development
Estrogen
Stimulates uterine growth, uteroplacental blood flow, causes proliferation of breast glandular tissue
Progesterone
Maintains endometrium, decreases contractility of uterus, stimulates development of breast alveoli, stimulates mat metabolism
Umbilical Cord and Membranes
Transport fetal blood to and from placenta
Umbilical Cord has this many veins and this many arteries
One Vein, Two Arteries. Vein carries O2 and nutrients from placenta –> Fetus, Arteries transport CO2 and Wastes from fetus to placenta
Fetal Membranes: Two:
Chorion and Amnion
Amniotic Fluid
700-1100 ml at term.
Oligohydraminos: <300 ml in third trimester
Polyhydraminos: >2L in third trimester
Amniotic Fluid Functions
- maintain temp
- equalize pressure and cushion from trauma
- protect from infection
- freedom of movement
- Provides fluid for fetus to swallow & breathe
- prevents embryo and membranes from tangling
- Repositioning for fetal waste (urine)
- Protects from pressure to contractions and aids in effacement and dilation of the cervix during labour
Growth
Increase in # of fetal cells, Increase in size of fetal cells
Development
Functional and structural changes that occur in fetal organ systems that have developed
Organogenesis
fetus’ organs and structures begin to form and function. During early period the fetal brain undergoes extremely rapid growth and development, using a considerable amount of total nutrients available.
Pre-Embryonic
0-2weeks. Conception –> 14 days of development. Fertilized egg differentiates into different specialized cells and travels down fallopian tube for implantation in uterus
Embryonic
2-8weeks. 14 days after conception –> end of 8th week. Rapid growth and development- organogenesis. Embryo’s heart starts beating, head is disproportionately large, arms and legs have joints & fingers distinct.
Fetal
9-40weeks. 9th week after conception –> birth. Viable at 22 weeks. Significant size increase in weeks 28-40
Nagele’s Rule
Subtract 3 months and add 7 days
5 Key Features of Fetal Circulation
- Fetal O2 needs are relatively low because O2 activities are carried out by maternal system via placenta.
- Placenta is organ of gas exchange
- Fetal lungs are hypoperfused & fluid filled
- Fetal Brain and Heart have increase O2 needs
- R –> L shunting occurs through foramen ovale & ductus arteriosus
TORCH- Infections in Pregnancy
Toxoplasmosis Other: Syphilis, Varicella, Hepatitis, HIV Rubella Cytomegalovirus Herpes
Intrauterine Growth Restriction
symmetrical or asymmetrical.
Factors: multiple gestation, poor maternal nutrition, maternal heart disease, maternal collagen disease, maternal HTN, fetal infection, drug/alcohol use, maternal infection, maternal autoimmune diease, fam hx of IUGR, smoking, antepartum hemorrhage, fetal cardiovascular anomalies, fetal congenital anomolies
Macrosomia
estimated weight more than 90th percentile.
Baby may experience birth trauma, asphyxia, and congenital anomalies such as heart defects
