Because of our biological clocks, women need to consider the timing of children a lot more urgently than men.

Startups take much longer than you’d think before they become successful. You should have a 5-10 year horizon, at least.

And the period between when you start the startup and when you can relax a little is grueling and all-consuming. The focus that’s required at first will probably force you to cut back on almost everything in your life, making a healthy work/life balance nearly impossible.

Startups are also unpredictable. In the early stages, you can’t plan too far in the future and arrange your life neatly around your plans, as you might with a job as an employee in the corporate world.

So you are working around the clock—so busy that you can’t focus on much outside of work, not knowing what startup disaster is around the corner, and maybe with no end in sight for years. But you know you want a family someday, either with your current partner or someone you haven’t even had the time to meet yet.

Because startups can cause you to neglect much of your own life, women founders need to be really proactive about their fertility. Especially if you want to buy more time before the window shuts on your childbearing years.

My advice: Freeze your eggs/embryos.

I wish I had. Life with my company whizzed by and it wasn’t until my late 30s when I had a child. After a year, I started working on baby #2. Three miscarriages later, I finally woke up to the urgency of the situation and went to a fertility doctor.

The next few years were consumed by IVF cycles. My obsession to have another baby grew with each failed cycle. I’d be on an emotional roller coaster waiting for the various results, praying that this time was the magical one. It never was. My eggs were just too old, I think. After 8 rounds with not one viable embryo to transfer, I decided I had to move on, to focus on my kid and all the really great things in my life. But the what-ifs still haunt me, privately.

Aspects of getting your eggs retrieved and/or frozen can be really awful. It’s extremely expensive if not covered by your medical insurance. The drugs can wreak havoc on moods and emotions. Between all the doctor’s appointments and the various shots (which cause serious bruising) you have to give yourself several times each day, it’s quite time consuming.  And it’s stressful. At least it was for me. The stakes feel so high.

But nothing is as awful as it not working out. It’s a type of depressing that’s difficult to describe concisely.

It might seem weird or somehow frivolous to freeze your eggs—and especially to freeze embryos if you’re already married. (Though it’s becoming more mainstream as companies offer egg freezing as an employee benefit.) But freezing is worth it simply because it gives you more options as you get older.

Until they go through it themselves, few people realize how hard Mother Nature can be in the fertility department. The older you are, the tougher the blows. So if you want a biological child, the best thing you can do is prepare. You don’t want to be like me and wake up one day and it’s too late.