Sickness review should be a positive not negative experience, its easy yo be afraid of these things, but if occ health and HR are properly involved, then there should be no problem at all. These procedures ,, be used to flag up issues that might be underlying and missed, for example, a person who is off with back pain, but hasn't had a workplace assessment to ensure that they are vetting the right support.
A stage 1, or whatever, doesn't mean you aren't 'allowed' to be off for a year, it simply means that your attendance will be watched more closely.
In my own care, I've had a difficult pregnancy, followed by post-natal depression, usual bugs etc., from having a child who, lets face it is normal, and would pick up anything in the street and eat it if I didn't stop them, plus attending child are, plus allergies, plus a closely followed second pregnancy, difficult first trimester, anti-depressant withdrawal, etc., etc.
I've worked closely with occ health, had various assessments etc., my latest basically said "difficult pregnancy plus toddler, can expect second pregnancy to be similar, she's gonna be off sick...... A lot"
just be honest and open, and you'll be fine love xx