Chapter 10 The prenatal period Flashcards
Biological events during pregnancy
Fertilization of the egg by the sperm
Implantation of the fertilized egg into the uterus
Embryonic or fetal growth and development
Placental development and function
Material changes related to the pregnancy
Duration of pregnancy
Full term
- 9 solar months - 10 lunar months
40 weeks
3 trimesters
Estimated date of delivery - Nageles rule
First day of last menstrual period + 7 days + 9 months
Fertilization
- Union of egg (Ovum) and sperm equals zygote
- Ovum and sperm in tube for five hours prior to union
- Zygote forms in fallopian tubes
- Sperm: must be uniform size, highly mobile, secrete enzymes to dissolve egg membrane
- Fertilized egg then prevents other sperm from entering
- Woman must have certain basal body temp; no adhesions
Conception occurs within 24 hours after ovulation
Implantation
Process of attachment + placental formation
- Placenta
Prevents direct exchange of blood between the mother fetus
Endocrine gland— Secretes essential hormones
- Zygote travels down tube for 6 days
- Implants on reaching uterus — Endometrium supplies nutrition for first 5 days
- Progesterone: stimulates the decidua, which supplies nutrition for embryo for up to 8 weeks
Fetal growth and development
Zygote progresses to embryo and then to fetus
- Physical development occurs through each structural system of the embryo
- Metabolic functions occur with physicals development
- Requires events occurring during specific periods and in certain order
- Congenital defect: abnormality in structure or function
- Genetic defect: abnormality that occurs at conception
Placental development
Placental develops through integration of embryonic and decidual cells
Formation of chorionic and amniotic membranes — amniotic fluid protects fetus
Allows maternal -fetal blood
some drugs may cross placenta
- Decreased placental function stimulates labour
- Post dates (great than 42 weeks) is major concern
Presumptive signs of pregnancy
Nausea or vomiting
Change in breast sensations and size
Increased urinary frequency
Missed menstrual period
Nausea or vomiting occurs in 50 to 90% of women
Health Canada has approved drug doxylamine-pyridoxine (Diclectin)
Doxylamine (antihistamine) and pyridoxine (B12) Side effect: drowsiness
Dietary changes; other nonmedical treatments
probable signs of pregnancy
Enlargement of their uterus
Softening of the uterine isthmus (Hegar’s sign)
Cyanotic dolour of the cervix and upper vagina (chadwick’s sign)
Softening of the cervix (goodells sign)
Asymmetrical softened enlargement of the uterine corner caused by placental development (Piskackes sign)
Positive test for HCG in maternal urine or blood
Changes in skin pigmentation
- Chloasma - hyperpigmentation
- Linea nigra - Dark line of skin down the middle of your abdomen
Positive signs of pregnancy
Detection of fetal heart tones by auscultation, ultrasonography, or doppler
Palpating of fetal body parts using leopoldo manoeuvres
Objective detection of fetal movements
Radiological or ultrasonographic demonstration of fetal parts
Adaptive changes of pregnancy
Urinary system
- 50 % glomerular filtration rate
- 25% increase in ureter diameter
- 80% urinary output
- 1500cc bladder capacity
Cardiovascular system
- 50% increase in cardiac output
- 30% - 45% increase in volume
- 10 BPM heart rate increase
Respiratory system
- 30-40% increase in tidal volume
- Diaphragm displaced upward
Musculoskeletal system
- Relaxation of joints
- Increased lumbar or dorsal spinal curves
- Separation of the symphysis pubis
Integumentary system
- Striae gravidarum
- Linea nigra
- Chloasma
Reproductive system
Changes: uterus, breasts, verging, vulva, ovaries
Uterus
- Increases from a “fist” size to capacity of 3.2-4.5 kg infant and placenta
- Fundus moves higher in abdomen
Breasts
- Enlarge in early pregnancy
- Late pregnancy: secrete colostrum
Vagina & Vulva
- Greater blood supply; more vaginal secretions
Preconception care of women
Public health agency of canada recommendations for preconception health and health care:
- Take 400 mcg of folic acid per day
- 150 minutes of moderate to vigorous physical activity per day
- Limit alcohol beverages to 2 glasses a day 10 per week (New recommended is 2 a week)
- Keep immunizations up to date
Sample recommendations
Vaccinations & supplementation
- Rubella, hepatitis B, folic acid
Chronic disease management
- Diabetes, hypothyroidism
Screening
-STLs, depression, violence
Lifestyle modifications
- Smoking
- Alcohol
- Drug use
- Obesity
Recommend weight gain during pregnancy
Healthy women with normal BMI: 11.3-15.5kg
Underweight women (BMI less than 25): 12.7-18.1kg
Overweight women (BMI grater than 25): 6.8-11.3kg
Obese women (BMI grater than 30): 4.0-9.07kg
- Infants of obese mothers risk: perpetuity, stillbirth, neonatal death, congenital abnormalities
- Obese mothers risk: compilations during pregnancy and delivery including disease, embolism, and pre-eclampsia
