Sept12 M3-Normal pregnancy and antenatal care Flashcards
placental dev
- trophoblast forms placenta with cyto and syncytio trophoblasts (cells). implants in endometrium
- primary and secondary villi of the placenta are formed (lacunae are formed by syncytios and then endometrial caps degen and their blood goes in lacunae)
abnormal placentation def (implantation)
excessive invasion of the placenta. it implants too deep in the uterus
maternal surface of the placenta
- discoid chorionic plate (decidual plate) with lobes, cotyledons, placental septae)
- looks like liver
- is a seventh of the fetus weight at term (500g)
fetal surface of placenta
-amnion and chorion, fetal vessels
hormones secreted during pregnancy
- placenta makes hCG (maintains CL), hPL (human placental lactogen), E and P
- pituitary, adrenal and thyroid Hs from mom
- fetal adrenal hormones
2 main cells of placenta
- cytotrophoblasts
- syncytiotrophoblasts
first hormone appearing a few days after implantation
hCG (produce by syncytiotrophoblasts).
hCG functions
- act on ovary to maintain CL and make it prod E + P
- act on thyroid to make it prod more TH (so TSH will drop in T1)
- stims prod of testo from fetal testis (if it’s a male) bc hCG is similar to LH (common alpha subunit. so hCG can act on LH-Rs)
hCG in normal intrauterine pregnancy
doubles every 48 hours DURING T1. then low range later in pregnancy
human placental lactogen fct
- proportion of hPL rises proportionally to placental mass (rises all throughout pregnancy)
- diabetogenic effect on the mother (more serum glucose, more lipolysis, less insulin action)
gestation diabetes mellitus (GDM) is caused by what
hPL
why CL stops making P after the first few weeks of pregnancy
fetal adrenals start making DHEA-S precusor which is aromatased by the placenta into estrogen
estrogen effect on the mother during pregnancy
- higher uterine blood flow and growth
- PG synthesis
- prolactin secretion
- other effects for maternal adapt to pregnancy
uterus changes how in pregnancy
- 50g in beginning. 950 at term
- initially hypertrophies. then distends at end of pregnancy
cervix and vagina in pregnancy
- cervix soften (ripening)
2. vagina mucosa thickens and stretches more easily
when does the uterus get out of the pelvis in pregnancy
at 12 weeks
when does uterus reach the belly button in pregnancy
20 weeks