CAIE IGCSE Biology 16.5.3 Sources of Oestrogen & Progesterone
Practise distinguishing where oestrogen and progesterone are produced during the menstrual cycle and pregnancy.
- Syllabus
- 2026–2028
- Course
- Biology 0610
Practise distinguishing where oestrogen and progesterone are produced during the menstrual cycle and pregnancy.
Fig. 1.1 shows the changes in the concentration of two hormones involved in the menstrual cycle.

Fig. 1.1
State the main site of progesterone production during pregnancy.
placenta ;