Consider the following statements: The expected date of delivery can be determined by: 1. Using the Naegele’s formula 2. Assessing uterine size during first trimester 3. Doing ultrasonography at 18 to 20 weeksWhich of these statements are correct?
A. 1, 2, and 3 B. 1 and 2
C. 2 and 3 D. 1 and 3
Answer.A (1,2, and 3)
Estimated due date (EDD)
1. Naegele’s rule: EDD = LMP—9 months + 7 days.
a. EDD
is early, if woman has shorter
preovulatory phase.
b. EDD is late, if woman has the
longer preovulatory phase.
2. Pelvic examination; Bimanual
examination of the pelvis and uterus. Because the uterus is usually in the pelvis
until 12 weeks’ gestation, early pregnancy is the best time to correlate
accurately uterine size and duration of gestation.
3. abdominal examination: Between 18 and 20 weeks, there is an excellent correlation between the size of the uterus and the gestation by weeks. The measurement in centimeters from the symphysis pubis to the top of the fundus should approximate the weeks of gestation. At midpregnancy (20 weeks), the fundus of the uterus is at the level of umbilicus.
3. abdominal examination: Between 18 and 20 weeks, there is an excellent correlation between the size of the uterus and the gestation by weeks. The measurement in centimeters from the symphysis pubis to the top of the fundus should approximate the weeks of gestation. At midpregnancy (20 weeks), the fundus of the uterus is at the level of umbilicus.
4. Sonography
a. First trimester: Fetal gestational age is best determined by measuring
the CRL between 7 and 12 weeks (variation ± 5 days).
b. Second trimester: By biparietal diameter (BPD), head circumference,
abdominal circumference, femur length. It is most accurate when done between 12
and 20 weeks (± 8 days variation). BPD becomes more accurate after 12 weeks.
c. Third
trimester: Least reliable (variation ± 16 days).
