Prenatal Calculation Methods PDF

Determination of Estimated Birth Date (this date was referred to as the estimated date of confinement (EDC).  Naegele’s Rule To calculate the date of birth by this rule, count backward 3 calendar months from the first day of a woman’s last menstrual period and add...

Determination of Estimated Birth Date (this date was referred to as the estimated date of confinement (EDC).  Naegele’s Rule To calculate the date of birth by this rule, count backward 3 calendar months from the first day of a woman’s last menstrual period and add 7 days. For example, if the last menstrual period began May 15, you would count back 3 months (April 15, March 15, February 15) and add 7 days, to arrive at a date of birth of February 22.  Naegele’s Rule It is used for estimating an expected due date based on the woman’s last menstrual period (LMP). It bases it calculation that the woman has a 28 day menstrual cycle (many woman vary) AND that it will be a gestation period of 280 days (40 weeks)… again this varies because gestation is slightly longer for first time mothers. Hence, Naegele’s Rule calculation in JUST an estimation  Naegele’s Rule Calculation Formula for Naegele’s Rule LMP Date Subtract 3 months from the LMP Add 7 Days to the LMP Add 1 Year (use this calculation formula for patients whose LMP falls between April-Dec)  Naegele’s Rule LMP Date Add 7 Days to LMP Then add 9 months (use this calculation formula for patients whose LMP falls between January-March rather than the other formula)  MC DONALD’S RULE- used to calculate AOG -using a tape measure , get the FH in cm –Fundic height (cm) x 2/7 = AOG in lunar mos. Fundic height (cm) x 8/7 = AOG in weeks  MC DONALD’S RULE- used to calculate AOG -using a tape measure , get the FH in cm –Fundic height (cm) x 2/7 = AOG in lunar mos. Fundic height (cm) x 8/7 = AOG in weeks  Exercises: 1. Savana 23 y/o consulted to her OB Gyne is amenorrheic for 3 mos. her LMP June 19, 2020, when is her EDC? 1. Mrs. Joy 30 y/o She consulted at BMC OB OPD Her LMP is November 28,2019  TERMINOLOGIES Pregnancy- Period of time between conception and birth during which the baby is developing within the uterus Gravida- medical term for a pregnant woman  OBSTETRICAL HISTORY History of Past Pregnancies - Include number of past pregnancies, outcome complications, labor time, method of delivery, complication of labor and complications of puerperium  OBSTETRICAL HISTORY TPALM T- Number of full term infants born after 37 weeks of gestation P- Number of preterm infants born before 37 weeks of gestation A- Number of spontaneous or induced abortions L- Number of living children M- multiple Pregnancies Gravida Para G- number of pregnancies irrespective of gestational age P- number of pregnancies that reached viability  Example: A woman's Obstetric History of 3 previous pregnancies with one full term infant, 1 born at 35 weeks ,1 at 39 weeks and an abortion at 8 weeks