Chapter 10 Reproductive System and Labour Flashcards
Describe the menestral cycle in terms of:
- concentrations of gonadotropic homormones
- concentrations of gonadal hormones
- events in the ovary
- events in the uterus
Describe the events that occur in each uterine phase:
- menstrual phase
- proliferative phase
- secretory or progrestational phase
- commencement of new menestral phase
Describe the events in each of the ovarian phases:
- follicular
- ovulation
- luteal
- new follicular
Relate the ovarian and uterine phases to the days in a cycle.
Describe changes in hormone levels during the menetral cycle.
Describe the events post-fertlization. Identify the timeline for each event.
Describe the events of implantation and identify the following:
- Decidua
- Cords of trophoplastic cells
- Inner cell mass
- surface of uterine lining
http://postimg.org/image/5lffwc173/
Decidua
Cords of trophoplastic cells (placenta)
Inner cell mass (baby)
surface of uterine lining
What are the physiological and hormonal changes of pregnancy?
Chorion (from trophoblastic cells)
- from day 8 until 4 months secretes hCG which keeps corpus luteum active
- corpus luteum produces progesterone & estrogen to maintain lining of uterus
Corpus luteum is essential for establishing and maintaining pregnancy in females. The corpus luteum secretes progesterone, which is a steroid hormone responsible for the decidualization of the endometrium (its development) and maintenance, respectively.
Hormonal secretion by the placenta
- by 4th month produces enough progesterone & estrogen
- relaxin which relaxes tissues of pelvis and cervix
Human chorionic somatomammotropoin (hCS) or human placental lactogen (hPL)
- helps prepare mammary glands for lactation
Corticotropin-releasing hormone (CRH) increases secretion of fetal cortisol (lung maturation) & acts to establish timing of birth
What hormones are produced by the placenta and what are their actions?
- Human chorionic gonadotropin (hCG)
- Relaxin
- Human chorionic somatomammotropin (hCS)
- corticotropin-releasing hormone (CRH is normally produced by hypothalamush when not pregrant, interesting!)
How does DHEA influence estrogen level?
DHEA is a precursor to estrogrens. Increased DHEA increases the production of estrogens because more material is available to produce the target hormone.
How do blood hormone levels change with growth of the fetus?
Human chorionic gonadotropin (hCG) produced by the chorion is less important after 4 months, because the placenta takes over the hormonal secretion of the corpus luteum
What are signs of pregnancy?
Pregnancy tests (for HCG)
- Urine (6 – 12 weeks)
- Serum (4-12 weeks)
5 weeks – Goodell’s sign
- In medicine, Goodell’s sign is an indication of pregnancy. It is a significant softening of the vaginal portion of the cervix from increased vascularization. This vascularization is a result of hypertrophy and engorgement of the vessels below the growing uterus.
6-8 weeks – Chadwick’s sign
- Chadwick’s sign is a bluish discoloration of the cervix, vagina, and labia resulting from increased blood flow. It is considered an indication of pregnancy, and can be observed as early as 6–8 weeks after conception,[1] and its presence is an early sign of pregnancy.
6 – 12 weeks – Hegar’s sign
- Hegar’s sign is a non-sensitive indication of pregnancy in women — its absence does not exclude pregnancy. It pertains to the features of the cervix and the uterine isthmus. It is demonstrated as softening of the uterine consistency and the possibility to palpate or compress the connection between the cervix and the fundus.[citation needed]
- The sign is usually present from 4 to 6th week till 12 weeks of pregnancy. It is more difficult to recognize in multiparous women.
16 weeks – Braxton Hicks contraction
How does the mother’s body respond to pregnacy?
Weight gain
- due to water retention
- baby, placenta and amniontic fluid
- 25-35lbs wt gain is recommended
Metabolism (increased by 15%)
Digestive System and nutrition
- 1-3 mnths - increase HCG levels produce nauseasa and hyperemitis
- acid reflux due to increased pressure in abdominal cavity
- constipation and hemorrhoids
- bloating
Cardiovascular System: blood volume – 30% above normal
- increased cardiac output
- Cardiovascular changes to meet needs of fetus
Respiratory System - diaphragm is raised
- movement is restricted
- rate is increased (shallow respiration deacreases the tidal volume)
- airways are dilated (usually no issue with perfusion of oxygen)
Urinary System
- more blood flow to the kidney
- increased glomerular filtration rate
- increased urine output
Others
- Integumentary system (nipple colour change, stritions and linea nigra)
- Musculoskeletal system (waddles)
Describe why hypotension may occur in pregnancy.
- Due to vasodilation of progesterone (especially the diastolic will decrease by about 10mmHg)
- Increase in blood volume
- Supine hypotensive syndrome: Aortocaval compression syndrome, is compression of the abdominal aorta and inferior vena cava by the gravid uterus when a pregnant woman lies on her back, i.e. in the supine position. It is a frequent cause of low maternal blood pressure (hypotension), which can in result in loss of consciousness[1] and in extreme circumstances fetal demise.[2]
Aortocaval compression is thought to be the cause of supine hypotensive syndrome. Supine hypotensive syndrome is characterized by pallor, bradycardia, sweating, nausea, hypotension and dizziness and occurs when a pregnant woman lies on her back and resolves when she is turned on her side.[3]
What is Labor and Parturition?
Parturition means giving birth; labor is the process of expelling the fetus
progesterone inhibits uterine contraction
Labor begins when progesterone’s inhibition is overcome by an increase in the levels of estrogen
Why estrogen level is increased at the end of the pregnancy?
- placenta stimulates fetal anterior pituitary which causes fetal adrenal gland to secrete DHEA
- placenta converts DHEA to estrogen
- estrogen overcomes progesterone and labor begins
Hormonal Factors That Cause Increased Uterine
Contraction?
Ratio of Estrogens to progesterone
- from 7th month onward estrogen secretion increased (progesterone remains constant)
Effect of oxytocin on the uterus
Describe the positive feedback cycle of oxytocin production during labour (positive feedback theory).
Notes:
Natural oxytocin is secreted by the posterior pituitary gland, which holds and secretes oxytocin produced by the hypothalamus.
Oxytocin also increases the sensitivity of baroreceptors in the cervix, thereby amplying the effect of applied pressure on subsequent production of oxytocin.
What mechanical factors increase the contractility of of the uterus?
- stretch of the uterus
- stretch of the cervix
How does one differentiate between true and false labor?
True labor
- contractions occur at regular intervals
- progressive pattern of contractions
- produces pain (back pain increases with walking)
- lower back sweeping around
- dilation of cervix with a discharge of blood-containing mucus in the cervical canal
- contraction progression is asscoiated with progression of cervical dilation and effactement (thinning)
False labor
- produces pain at irregular intervals (no pattern)
- not impacted by activity, pain is constant
- no cervical dilation
What are Braxton Hicks contractions?
Braxton Hicks contractions, also known as prodromal labor or practice contractions, or incorrectly as false labor, are sporadic uterine contractions that sometimes start around six weeks into a pregnancy. However, they are not usually felt until the second trimester or third trimester of pregnancy.[1]
Usually occur around 38-39 wk, common with G1, P0 women
