Pregnancy Flashcards
Fertilization
100% of sperm delivered to vagina 3% survive to cervix 0.1% survive to uterus 0.001% survive to oviducts Oviducts is the site of fertilization
Implantation of blastocyst
Implants at 7-10 days
Summary of events from ovulation and fertilization to implantation
1 day after LH peak = ovulation in the ovary
2 days after LH peak= fertilization in the Fallopian tube
2-4 days after LH peak = cell division to ~32 cells in the Fallopian tube
5 days after LH peak = blastocyst enters the uterine cavity
6-7 days after LH peak = implantation in the uterus
9-10 days after LH peak = human chorionic gonadotropin (hCG) from implanted blastocyst (trophoblast cells) rescues corpus luteum, location = trophoblast -> maternal ovary
Development
After implantation =
Placenta develops
Gas and nutrient exchange
Endocrine organ secreting essential pregnancy hormones (hCG) maintains corpus luteum until placenta takes over at 3 months
Gestation
Pregnancy
About 38 weeks from conception
Physical changes within mom =
Uterine enlargement
Breasts enlarge and develop ability to produce milk
Volume of blood increases 30%
Weight gain
Respiratory activity increases by about 20%
Urinary output increases
Kidneys excrete additional wastes from fetus
Nutritional requirements increase
Fetal development
Embryo phase = weeks 1-8, development of all systems, 23 Carnegie stages, most susceptible
Fetal stage = weeks 9-36, growth, continued differentiation of organs and tissues
4 weeks gestation
Somites are forming (spinal cord)
Ear and eye start to form
5 weeks gestation
3 weeks since implant and missed period Heart is beating Placenta is fully operational Mouth, liver, kidney, digestive systems Arm and leg buds
7 weeks gestation
13-17mm
Foot and hand rays
Muscle development
8 weeks gestation
23-28mm Genitalia differentiate (external) Bones start to ossify Rays separate into toes and fingers First trimester is the main period of organogenesis Second and third trimesters = growth
12 weeks
Bone ossification continues 6-9cm long Smiling Sucking Frowning Has bones, skin, and hair Kicking and moving Hormone secretion
16 weeks
Grasping
Reacts to sounds
Kicks can be felt
20 weeks
Scalp hair
Lung development
Can survive outside womb at 24 weeks
Parturition (stages of labour)
Cervical dilation = higher oxytocin, longest stage, 2-24hours
Delivery of baby = cervical dilation and effacement is complete, last 30-90minutes
Delivery of placenta = uterine contractions separates placenta form uterine wall, usually within 15-30minutes after baby is born
After delivery uterus shrinks to presentational size (involutional)
Etopic pregnancy
Ovum attaches outside uterus
Usually happens in Fallopian tubes
Symptoms = acute pelvic pain, vaginal bleeding
Pregnancy termination
Spontaneous abortion
Aka miscarriage
Natural termination before fetus is viable
Symptoms = vaginal bleeding, cramping and pelvic pain
D and C
Hypremesis gravidarum
Excessive vomiting during pregnancy
Treatment = IV fluids or oral fluids
Second pregnancy better
Toxaemia (pre-eclampsia)
Third trimester
Symptoms = hypertension, sudden weight gain, proteinuria, edema in face, hands, and feet
Treatment = frequent monitoring, delivery
Abruptio placentae
Separation of placenta from uterus
Partial separation = may be asymptomatic
Complete separation = severe abdominal pain, vaginal bleeding, shock, decreased fetal heart tones
Delivery
Placenta Previa
Placenta in lower uterus (near or over cervix) Symptoms = bright red vaginal bleeding Third trimester Vaginal delivery if mild C-section if severe
Division errors
Identical twins = complete division, early stage
Conjoined = incomplete division, later blastula stage
Cleft lip/palate
Division errors in weeks 2-8 Genetic disposition Environmental factors = Alcohol Cigarette use Organic solvents Exposure to lead Illegal drugs Vitamin deficiency
Defects during pregnancy
By teratogens (eg - X-rays, syphilis) Congenital rubella syndrome (CRS) = malformations of fetus, time of maternal infection determines type and severity, malformation of heart, eyes or brain, liver, spleen, and bone marrow problems, growth retardation, deafness
Smoking effects
Decreased fertility Placenta abruption Spontaneous abortion Low birth weight Increased perinatal death (20+weeks) Increased neo-natal mortality Premature birth Congenital malformations Behavioural problems (eg - ADHD) Increased childhood cancers
Fetal alcohol syndrome
Premature differentiation of mesenchyme (first 8 weeks)
Cell atopsis
Reduced head size and distinctive facial features
Neural effects
Variable degree of birth defects and mental retardation
DNA damage?
ADHD?
Dietary
Folic acid Synthesizes, repairs, and methylates DNA Needed for cell division RBC production Found in fruits and veggies
Neural tube defects
Due to folic acid deficiency
Spina bifida = incomplete vertebrae formation, incomplete closure
Meningocoele = spinal cord lining protrudes
Cerebral palsy
Decreased oxygen delivery during pregnancy and delivery
Muscle tightness or spasms
Difficulty with motor skills (walking or running, writing or doing up buttons)
Difficulty in perception and sensation
