A study divides healthy females into two groups (A and B). Both groupsare composed of those who have been sexually active for at least 2 yearsand are not pregnant at the beginning of the experiment. The subjectsweigh about the same amount, and none smoke cigarettes, althoughsome drink alcohol occasionally. Group A individuals receive a placeboin the form of a sugar pill each morning of their menstrual cycles. GroupB individuals receive a pill containing estrogen and progesterone eachmorning of their menstrual cycles. Then plasma LH levels are measuredbefore, during, and after ovulation. The results are as follows:Group 4 Days BeforeOvulationDay ofOvulation4 Days AfterOvulationA 18 mg/100 mL 300 mg/100 mL 17 mg/100 mLB 21 mg/100 mL 157 mg/100 mL 15 mg/100 mLThe number of pregnancies in group A is 37/100 females/year. Thenumber of pregnancies in group B is 1.5/100 females/year. Whatconclusion can you reach on the basis of these data? Explain themechanism involved.
A study divides healthy females into two groups (A and B). Both groups
are composed of those who have been sexually active for at least 2 years
and are not pregnant at the beginning of the experiment. The subjects
weigh about the same amount, and none smoke cigarettes, although
some drink alcohol occasionally. Group A individuals receive a placebo
in the form of a sugar pill each morning of their menstrual cycles. Group
B individuals receive a pill containing estrogen and progesterone each
morning of their menstrual cycles. Then plasma LH levels are measured
before, during, and after ovulation. The results are as follows:
Group 4 Days Before
Ovulation
Day of
Ovulation
4 Days After
Ovulation
A 18 mg/100 mL 300 mg/100 mL 17 mg/100 mL
B 21 mg/100 mL 157 mg/100 mL 15 mg/100 mL
The number of pregnancies in group A is 37/100 females/year. The
number of pregnancies in group B is 1.5/100 females/year. What
conclusion can you reach on the basis of these data? Explain the
mechanism involved.
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