You’re unlikely to be able to influence your baby’s future sleep patterns while you’re pregnant as they’ll just sleep like a newborn, which is a lot but fragmented over a 24 hour period (sorry to break the news). What you can do however is visit your own sleep and get good sleep habits in place.
1. Get used to going to bed early.
2. Introduce a simple bedtime routine that allows you to wind down and relax.
3. Change your diet if necessary to support sleep, e.g. don't eat high fat or high sugar foods late at night.
4. Exercise at the right time of day to support sleep.
5. Make sure that you expose yourself to lots of natural daylight throughout the day to support your circadian clock.
If during your pregnancy you're burning the candle at both ends and not respecting your sleep, it will be much harder to respect sleep when your baby is born.
In fact, when your baby is in utero they borrow your circadian rhythm through your circadian hormones that come in via the placenta. Therefore, if you have very haphazard sleep patterns while pregnant, some research suggests that your baby may inherit similar patterns.
So rather than worrying about whether your baby will or will not sleep (because inevitably you will have no control over that when they're born), a better place to start is to address your own sleep habits and hygiene.