by / Monday, 21 February 2011 / Published in OB/GYN, Physiology

Here are some high-yield reproductive endocrinology facts:


What’s the #1 reason an adult female goes to the doctor? Menstrual irregularity

What’s the #1 reason why a teenage female misses school? Dysmenorrhea (painful menses)

Naegle’s rule – based on a 28-day menstrual cycle.


Calculation of estimated date of confinement (EDC):

– starts with last first day of menses + 9 months, + 1 week

– if there is variation in the womans cycle, add or substract this # of days.

Term pregnancy = 37-42 weeks (>42wk is post-term)

avg birthweight = 2500g – 3500g (ie 5-7lbs)

SGA – small for gestational age   LGA – large for gestational age

Post-term baby – Wharthon’s jelly will be thickened (more accurate than dry skin or curled nails)

SGA – caused by inadequate nutrition to the baby, mother’s vessels will be constricted (hypertension – caused by many diff things such as: smoking, cocaine, etc)

LGA – baby eating too much (#1 cause is diabetes).  Another rare cause is twin-twin transfusion (only possible if twins are mono-chorionic (ie. attached to one placenta)… 50% of the time we will lose one baby (one gets anemia, one gets polycythemia, both lead to heart failure that kills the baby).  30% of the time we lose both of the babies.

MGMT of twin-twin transfusion–> if one dies, must leave it in there and let the other one go to term (because antigens match, there will be no consequence of doing this)

Naegle’s rule allows us to make following division of events:

1-10 days –> proliferative phase (controlled by estrogen)

10-14 days –> ovulatory phase (controlled by leutinizing hormone)

14-28 days –> luteal phase (ie secretory phase), controlled by progesterone

** secretory phase is fixed in all women, almost always fixed at 2 weeks.

** proliferative phase is what varies the most between each female.

Figure out ovulation?

End of secretory phase – 2 weeks = ovulation occurs (approximate)


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