Diagnosis of Pregnancy

Question 1

When is hCG secreted in the maternal circulation?

Answer 1

5-7 days after fertilization

Question 2

How long does it take to double serum levels of hCG, and how long does this pattern continue?

Answer 2

Doubles every 29-53hrs for the 30 days after implantation

Question 3

What are the methods for detecting hCG? What’s the earliest that each method can detect?

Answer 3

Serum: 9 days after conception
Urine: Around missed menses

Question 4

What is the risk of a pregnancy in a patient with an IUD?

Answer 4

Increased risk of an ectopic pregnancy

Question 5

What is Naegle’s Rule?

Answer 5

Used to calculate estimated date of delivery (EDD): LMP-3mo+7day = EDD

Question 6

What is the best tool for calculated EDD?

Answer 6

US

Question 7

When does cardiac activity become visible on an US?

Answer 7

5.5-6 weeks

Question 8

Why is it important to determine an accurate EDD?

Answer 8

Determine pre or post maturity, eligibility for out of hospital birth; timing for tests/procedures; determining IUGR