Parturition and Menopause Flashcards
normal pregnancy duration
- A normal pregnancy lasts for ~ 40 weeks or 280 days after the last menstrual period
- Naegele’s formula can be used to estimate the date of birth: add seven days to the last menstrual period, subtract three from the month and add one to the year. For example, if the LMP was 14.8.98, add 7 days = 21.8.98, subtract three from the month = 21.5.98, add one year = 21.5.99.
signs of labour
- Mucous plug in the cervix, which acts as a seal during pregnancy, is passed as a blood stained or brownish discharge
- Coordinated muscular contractions are generated in the upper part of the uterus, the fundus –> helps to gradually open, or dilate, the cervix
- Water breaks: Amniotic sac surrounding the baby ruptures, or breaks, allowing colourless amniotic fluid to pass out through the birth canal
three stages of labour
- Dilation of cervix: Longest stage of labor
o Cervical opening enlarges eight to ten centimeters - Delivery of the baby:
o Begins when cervix is completely dilated
o Baby moves farther down the birth canal, usually head first.
o Mother pushes, and the muscles in the uterus contract to push the baby out
o Baby’s head will be visible = called crowning
o Ends with the delivery of the baby - Delivery of the Placenta:
o Expulsion of the afterbirth = placenta is expelled after delivery
o If this does not occur naturally the physician removes it
types of birth - natural vs induced
Natural birth: Delivery of a baby without using drugs or surgery during birth
Induced labor: Stimulation of uterine contractions before they occur spontaneously
types of birth - breech vs cesarean section
Breech birth: When baby delivered either foot first or buttocks first
Cesarean Section (C-Section): Form of childbirth in which a surgical incision is made through a mother’s abdomen and uterus to deliver the baby
types of birth - episiotomy vs vacuum extraction vs forceps
Episiotomy: Incision between the vagina and anus (perineum) help with crowning of the baby, to prevent muscles from tearing
Vacuum extraction: Assist mother if she becomes too tired, cup on baby’s head with slight suction
Forceps: To guide baby’s head out of birth canal
epidural
- Pain relief administered in the woman’s lower back using a needle
- Local anaesthetic injected in to the space around the spinal nerve
- Injection is usually made in the lumber region at the L2/3 or L3/4 space
- Usually done when 4-5cm dilated with regular contractions (epidural might slow down contractions)
apgar scale
assessment test of the newborn on a scale of 1-10, activity, pulse, grimace (reflex), appearance (skin colour,) respiration
7+ baby in good condition
4-6: baby needs assistance
<4: baby needs life saving techniques
pregnant uterus and associated hormones
myometrium: oxytocin receptors
placenta & placental villi: progesterone, oestrogen, prostagladin
decidua: PGF2
cervix: IL-8
amnion: PGE2
chorion: PG dehydrogenase
phases of uterine function
- Hormonal trigger to initiate parturition in humans has not been identified
- Most likely to be of fetal origins
regulation of parturition - cortisol
- Increased levels of Corticotropin Releasing Hormone (CRH)
- Stimulates fetal pituitary to release ACTH (adrenocorticotropic hormone)
- Stimulates mature fetal adrenal glands to release:
A) Cortisol - Stimulates fetal lung development
- Production of surfactant
- Ready to breath air
- Stimulates PG synthesis
regulation of parturition - DHEA
(dehydroepiandro-sterone sulfate)
- Produced by the adrenal cortex
- Converted to Estrogen in the placenta
o decrease in Prog/Estr ratio
o Increased gap junctions in myometrium: Prepared for contraction
o Increased oxytocin receptors: Uterus can respond to oxytocin
o Increased prostaglandin production: Causes cervical ripening, Uterine contractions
important hormones (progesterone and oestrogens)
Progesterone (maintains pregnancy) o Relaxation of uterine muscle o Suppresses spontaneous contractions o Down-regulates oxytocin receptors o Inhibits formation of gap junctions myometrium
Estrogens (labor)
o Stimulate myometrial contractions
o Up-regulates oxytocin receptors
o Stimulates formation of gap junctions myometrium
o Preps uterus for coordinated contractions
- Prostaglandins stimulate myometrial contractions
- Oxytocin is the strongest stimulator of uterine contractions
causes of premature labour
chronic inflammation, acute infection, non-inflammatory vascular lesions, growth disorders -> autocrine/paracrine/hormones/cytokines –> premature uterine contraction
mechanical disorders –> matrix metalloproteinases + TIMPS –> increased matrix degradation –> decreased tensile strength –> premature rupture of the fatal membranes
maternal stress –> autocrine/paracrine/ hormones/cytokines –> premature uterine contraction
foetal lung development
terminal bronchioli: 15-25 weeks gesation
primitive alveoli: from 26 weeks gestation
mature alveoli: after birth
comparison of male and female pelvises
- The pelvic girdle = formed by 2 hip bones, sacrum & coccyx
- Each hip bone is formed by fusion of ilium, ischium and pubis
- The hip bones are joined anteriorly to form the symphysis pubis and each articulate with the sacrum through the sacro-iliac joint
female pelvic characteristics
tilted forward, adapted for childbearing; true pelvis defines the birth canal; cavity of the true pelvis is broad, shallow, and has a greater capacity
less thick bones, lighter, thinner and smoother
acetabula smaller, further apart
male pelvis characteristic
tilted less far forward, adapter for support of a male’s heavier build and stronger muscles; cavity of the true pelvis is narrow and deep
thicker bones, heavier, markings are more prominent
acetabula larger and closer together
miscarriage
A miscarriage is the loss of a fetus before the 20th week of pregnancy
- The medical term for a miscarriage is spontaneous abortion, but the condition is not an abortion in the common definition of the term
- 50% of pregnancy ends in miscarriage, but usually before a women misses her menstrual period
- 15% of recognized pregnancies end in a miscarriage
- Symptoms: Bleeding which progresses from light to heavy, severe cramps, abdominal pain, fever, weakness, back pain
stillbirth
Stillbirth is the death of a baby during pregnancy after 20 weeks of gestation but before delivery
- Stillbirth occurs in ~ 1 : 200 pregnancies
Possible Causes:
- High Blood pressure
- Diabetes
- Blood-clotting problem
- Infection of mother or fetus
- Placental abruption (Tearing away from uterus to soon)
- Umbilical cord twisting, which can cut off oxygen to fetus
- Fetus may have a birth defect or slowed growth development
menopause and causes
- Has occurred when menses have ceased for an entire year
- No equivalent to menopause in males: Males continue to produce sperm well into eighth decade of life, though numbers and motility decrease
- Declining estrogen levels cause:
o Atrophy of reproductive organs and breasts
o Irritability and depression in some
o Hot flashes as skin blood vessels undergo intense vasodilation
o Gradual thinning of skin and bone loss
o Increased total blood cholesterol levels and falling HDL
changes due to menopause
- Postmenopausal vagina shrinks in diameter, splits and tears easily and may cause severe dyspareunia = difficult or painful sexual intercourse
- Decrease in elastic capacity of the bladder -> urinary frequency, nocturia
- Average age of menopause = 50 to 55 years
- Depletion of ovarian follicles/ova
treatment of menopause
- Treatment: estrogen-progesterone preparations has been given for years
o Women’s Health Initiative research reported increased risk of heart disease (51%), invasive breast cancer (24%), and stroke (31%), and dementia risk doubled
o Smallest doses for shortest time are allowable to reduce symptoms if no history of breast cancer and no presence of mutated BRCA gene
hormone replacement theory (HRT) and CV disease
HRT is reported to reduce overall risk of CVD by 25-50%
Mechanisms
- Reduced cholesterol levels
- Restores endothelial function
- Decreases systolic and diastolic blood pressure
- Increases cardiac output
- Decreases vascular resistance
male climacteric - symptoms
- Circulating levels of testosterone decline with age
- Depression nervousness
- Flushes and sweats
- Decreased libido
- Erectile dysfunction
- Tiredness
- Poor concentration and memory
- Declining sperm production and motility
