Exam 1 - Fetal Development and Nutrition during Pregnancy Flashcards
Pregnancy
- 10 Lunar Months, 9 Calendar Months, 40 Weeks, 280 Days
- Length of Pregnancy computed from the first day of the last menstrual period
Naegele’s Rule
- Determine the first day of the last menstrual period
- - subtract 3 months, add 7 days and adjust year
Intrauterine Development
o Ovum/preembryonic (days 1--14) o Embryo (2-8 weeks) o Fetus (9 weeks ~ delivery)
Amniotic Fluid
- Cushions the embryo and fetus
- Controls Temperature
- Promotes symmetrical growth
- Prevents fetal adherence to the amnion
- Allows freedom of movement
- Circulating volume at 10 weeks 30ml
- Circulating volume at 20 weeks 350 ml
- Circulating volume at term 800-1000 ml
Umbilical Cord
- Formed about the 5th week
- Two Arteries carry deoxygenated blood from the embryo to be oxygenated by the placenta
- One Vein returns oxygenated blood from the placenta to the embryo
- At term ranges from 30-90cm long and 2cm wide
Fetal Period (9 wks to delivery)
- All Major systems present in their basic form
- Dramatic growth and refinement of structures occurs
- Teratogens less likely to damage already formed structures
- CNS is still vulnerable throughout entire pregnancy
Viability
- Viability possible at 20 weeks although survival more likely after 24 weeks
- A 24 week gestation baby is about the size of a beanie baby and weighs in at about 1.5 lbs
Summary of Fetal Circulation
- Blood oxygenated in placenta
- Returns to fetus through U vein
- Passes through Ductus venosis to inferior vena cava
- From IVC to RA
- Shunts through FO into LA and enters systemic circulation
- Deox blood returns to fetal heart (RA) via SVC
- Travels through Tricuspid valve to RV and then into Pulmonary arteries
- From Pulm arteries through Ductus Arteriosis to Descending Aorta
- From Descending Aorta to Umbilical arteries back to placenta for oxygenation
Respiratory System
• 4th-17th week larynx, trachea, bronchi, and lung buds form
• 16th-24th week bronchi and terminal bronchioles enlarge, vascular structures and primitive alveoli are formed
• 24th-birth more alveoli form
o Type I and II alveolar cells produce surfactant which is present in adequate amounts for survival by 32 weeks
Determining Fetal Lung Maturity
• Lecithin/Sphingomyelin (L/S) present in surfactant
• Surfactant is detectable at approx. 21 weeks
• L/S present in a ratio of 2:1 in mature fetal lungs
o Specimen obtained from amniotic fluid via amniocentesis
o In conditions that slow down fetal lung maturity a ratio of 3:1 is necessary. PG (phosphatidylglycerol) test may also be done.
Betamethasone IM
injection given to women in PTL to accelerate fetal lung maturation)
Cause of Deceleration of fetal lung maturity
o Pre-existing DM or Gestational DM
o Chronic glomerulonephritis
Renal System
- 5th week kidneys form
- 9th week begin to function
- Excretes urine to form majority of amniotic fluid
- Not an organ of excretion until after birth
Oligohydramnios
(too little amniotic fluid) indicative of renal dysfunction
Sensory Awareness
- 20 weeks: distinguishes taste
- 24 weeks: responds to sound
- Fetus reacts to temperature changes
- Fetus can see
- Eyelids open in the third trimester.
Reproductive and Musculoskeletal Systems
- 7th week sex differentiation occurs
- 9th week distinguishing characteristics appear and are fully differentiated by the 12th week, although difficult to see by ultrasound.
- Will be able to see clearly via ultrasound on the 20th week
Integumentary
- 4th week skin development begins
- Vernix Caseosa (thick, white, cheesy substance) covers and protects skin and is thickest at 24 weeks and thinnest at term
- Lanugo appears at 12 weeks (fine downy hair) and thins and disappears by term gestation
Immunologic Systems
- IgG crosses placenta to provide passive immunity
- Fetus produces IgM by the end of the first trimester
- IgA not produced by fetus but is present in colostrum
Quickening
• 16-20th week “Quickening” occurs (mother can feel baby moving or fluttering)
o Sometimes occurs earlier in multipara or later in primipara
Dizygotic
two separate ova are released and fertilized, not identical, two amnions, two chorions, and two placentas which may be fused
Monozygotic
developed from one fertilized ovum and are identical. Most often, there are two amnions, one chorion, and one placenta
Congenital
– condition present at birth
– Congenital disorders may be inherited, may be caused by environmental factors, or by inadequate maternal nutrition
Recommendations for Total Weight Gain
normal BMI (19.8-26 BMI) = 25-35 lbs
Pattern: 3.5 lbs during first trimester, then second and third 0.5 to 1 lb per week
Low BMI 29 = >= 15 lbs
FALSE ANEMIA
increase in plasma dilutes RBC’s which results in a decreased concentration of Hgb and Hct
Iron supplements
- recommended starting at 12 weeks gestation
- Iron should be taken on an empty stomach with a beverage high in ascorbic acid such as orange juice to enhance absorption
- Iron supplementation not for everyone (Ex. high levels of iron assoc w/ GDM)
Folic Acid or Folate
important in adequate amounts prior to conception (400 mcg)
• Prevents Neural Tube Defects
• Found in green leafy veggies, broccoli, legumes, etc.
WIC
• The WIC target population are low-income, nutritionally at risk
o Pregnant women (through pregnancy and up to 6 weeks after birth or after pregnancy ends).
o Breastfeeding women (up to infant’s 1st birthday)
o Nonbreastfeeding postpartum women (up to 6 months after the birth of an infant or after pregnancy ends)
o Infants (up to 1st birthday). WIC serves 45 percent of all infants born in the United States.
o Children up to their 5th birthday.
Benefits of WIC
o Supplemental nutritious foods
o Nutrition education and counseling at WIC clinics
o Screening and referrals to other health, welfare and social services
• Nutrition Related Discomforts of Pregnancy
Tx for Nausea and Vomiting
o Eat dry starchy foods on awakening
o Separate fluids from solids
o Eat protein rich food before bed
o Avoid spicy and high fat foods
Tx for Constipation
o Eat high fiber foods
o Drink plenty of fluids (have to balance w fiber)
o Physical Activity
Pyrosis (heart burn)
o Eat small frequent meals
o Don’t lie down right after eating
