menstruation and pregnancy Flashcards
what does the corupus luteum produce?
oestrogen and progesterone
how long will LH maintain hormones in corpus luteum?
around a week or they will need another signal - this decline is what causes the bleed
what are the cascade events in withdrawl of sex steroid?
- vasoconstriction
- tissue hypoxia
- connective tissue breakdown with production of enzymes
- fragmentation
what controls blood lose during menstruation?
coagulation factors - concern if blood loss if more than 80mL
what does ectopic mean/
when part of the lining is being shed in the wrong place and is either on the outside of the cervix or the fallopian tube
how does endometriosis arise/
- Much of it by reflux menstruation – endometrial tissue fragments shed at menses passing through the Fallopian tube, then becoming established in ectopic sites.
- some endometriosis cannot be explained in this way sometimes you see it at remote sites that are no accessible to shed tissue. Stem cells can be remote sites and change into endometrium
- Alternatively it may arise de novo from progenitor cells in ectopic tissues
- Family history is a risk factor
what are the symptoms of endometriosis?
- pelvic pain
- infertility
what are the treatment options for endometriosis?
- surgery can be used to remove the lesions
- NSAID for pain management
- blocking hormonal cycle
which drugs can be used to block hormonal cycle?
o Aromatase inhibitor – catalyzing formation of oestrogens
o Combined oral steroid contraceptive
o Gonadotropin-releasing hormone (GnRH) modulators – bucarilin way of shutting down the cycle
when does ovulation occur?
between days 14 to 28
where does fertilisation occur?
usually within the upper fallopian tubes, if sperm is present.
what is pre-implantation?
around 6 days.
occurs as embryo moves down tube.
what is the blastocyst?
where implantation takes place this stage needs to be reached to allow implantation to occur
how does contracpetion work?
usually doesnt prevent fertilisation but instead blocks progession of pregnancy by preventing implantation
what is interstital implantation?
embryos must develop to blastocyst stage to be able to implant.
embryo has to get under the surface and implant deep, they go dwon into suface within a week so allow pregnancy to progress.
what is the implantation window?
mainly related to the LH peak around 36 hours post ovulation.
around day 7 embryo is receptive and if you leave it past this it wont be a successful pregnancy
what is hCG?
- The placenta produces the polypeptide hormone hCG from the hatched blastocyst stage onwards
- It appears in measurable quantities in maternal blood (and urine) soon after implantation (used for pregnancy testing)
- Chorionic refers to the outer cells of the placenta
- hCG rescues the corpus luteum (so P continues to rise)
- Lack of timely appearance of hCG probably accounts for the ‘closure’ of the receptive period for implantation
what are the levels of oestrogen and progesterone like in pregnancy?
much higher than a normal cycle and continue to rise throughout.
when does hCG peak in pregnancy?
around 8-9 weeks, although it is still around it does decline after this time
what is progesterone?
- regulates the rate of transport of the egg/embryo through the Fallopian tube, lined by cells that have cilia so they beat and move the embryo down towards the uterus
- prepares the uterus to receive the implanting blastocyst
- sustains the uterine lining (endometrium) throughout pregnancy
- inhibits myometrial contractility, until the end of pregnancy
what is the luteoplacental endocrine switch?
- At 7-9 weeks, the placenta takes over the production of estrogen and progesterone from the corpus luteum
- Still produces steroid but it is not the main source as the placenta takes over
when does the majority of miscarriages occur?
between week 7-9 when the placement takes over as the main source of steroid production
how are steroid hormones produced in pregnancy?
cholesterol is imported into the placenta and converted into progesterone where is goes to the fetues and is convertred to androgens.
the oestroegn is then moved back into circulation.
placenta sends out lots of signals to continue metabolims and prepare for lactation
what is an ectopic pregnancy?
tubule gets blocked
can occur in the fallopian tube as it is where fertilisation takes place
similar to endometritsis
what are the symptoms of an ectopic pregnancy?
- abdominal pain
- hCG detected from pregnancy test, but this may be formed from a tumour.
- scan– no intrauterine body?
- ectopic pregnancy?
- tubal rupture can be fatal!
- medical management or surgery?
- methotrexate (folate antagonist, blocks DNA synthesis
how can you terminate a pregnacy?
- surgically or medically
- up to 24 weeks, majority are done by the 13th week\
- drug similar to progesterine and binds to receptors acting as a antagonist
what drug is mainly used to terminate pregnancy/
RU486
what is human placental lactogen?
- hPL modulates intermediary metabolism by changing the level of insulin-like growth factor (IGF) in
- in turn this increases glucose and amino acid availability to the fetus to be able to grow. Important through placenta to allow growth of fetus
- polypeptide hormone
how do hormones control labour?
progesterone suppresses myometrial contractility until late pregnancy. Initation of labour may be via inflammatory mediators. Things change when humans evolved – you have to have a lower uterine cervix which is capable to hold the conceptors in place.
what is oxytocin?
- Peptide hormone (nine-mer)
- Released from posterior pituitary
- Levels rise in last trimester
- Myometrial receptors increase markedly around week 36
- Used, with PG analogues, to induce labou
what is given if you need to advance mature fetal lungs/
• Glucocorticoid treatment
what are the main types of drug used in pregnany which are safe?
- most diffuse across placenta and into fetal ciruclation
- lipohilic drugs (unionised)
- weakly basic
- larger molecules
what are the problems with valproate?
used for the treatment of epilepsy
not safe to use in pregnacy as it is linked to birth defects and life long altering behavioral and learning issues
what is pre term?
before 37 weeks
approx 5-10% of babies are premature
what are the main thoughts on drug use in pregnancy?
- Try to avoid all drugs in the 1st trimester
- Essential therapy taper to lowest effective dose prior to conception
- If appropriate switch to a safer drug during pregnancy
- Use lowest effective dose for minimal duration
