Question 221#

Which one of the following is true regarding routine prenatal screening ultrasonography before 24 weeks gestation?

A. It has been shown to reduce maternal mortality

Correct Answer E:

Routine ultrasonography at around 18-22 weeks gestation has become the standard of care in many communities. Acceptance is based on many factors, including patient preference, medical-legal pressure, and the perceived benefit by physicians. However, rigorous testing has found little scientific benefit for, or harm from, routine screening ultrasonography.

Question 222#

The recommended time to screen asymptomatic pregnant women without risk factors for gestational diabetes is:

A. In the first trimester

Correct Answer C:

The recommended time to screen for gestational diabetes is 24-28 weeks gestation. The patient may be given a 50-g oral glucose load followed by a glucose determination 1 hour later.

Question 223#

As a single measurement, which one of the following provides the most accurate estimate of gestational age by ultrasound determination during the second trimester?

A. Transabdominal diameter

Correct Answer B:

All of the options listed can be assessed by ultrasonography. Crown-rump length is a very accurate parameter in the first trimester, but the biparietal diameter is the most accurate parameter during the second trimester. Both have a 95% confidence level of being within 5-10 days of the actual gestational age when used at the proper time.

Question 224#

Which one of the following is an evidence-based clinical recommendation for maternity care?

A. All pregnant women should be screened serologically for herpes simplex virus infection

Correct Answer C:

All pregnant women should be screened for asymptomatic bacteriuria due to the increased risk for pyelonephritis and preterm labor. All pregnant women should also be screened for active hepatitis B, syphilis, and HIV infection. Only at risk women (those 25 years of age or younger and those at risk of STDs) need to be screened for Chlamydia. Routine screening for bacterial vaginosis is not recommended.

Question 225#

Which one of the following sonographic measurements is most accurate for estimating gestational age?

A. Amniotic sac size at 5 weeks of pregnancy

Correct Answer B:

Estimation of gestational age by ultrasound is most accurate early in the first trimester and begins to decline by 22 weeks gestation. Crown-rump length is typically used to estimate gestational age before 13 weeks gestation. After 11 weeks gestation, combinations of biparietal diameter, femur length, head circumference, and abdominal circumference are used to estimate the gestational age. These factors are used by the software that generates ultrasonography reports.