Marriage and Children

Securing an heir is essential in Mount & Blade II: Bannerlord, but the mechanics of pregnancy can sometimes feel mysterious. This guide breaks down exactly how the game calculates the chance of a new family member arriving.

Pregnancy is based on a daily probability check, influenced by age and proximity.

How to Have a Baby

The requirements are simple, but specific:

1. Marriage: You must have a spouse.

2. Proximity: You and your spouse must be in the same location. This can be:

   • Waiting in the same Settlement.

   • Your spouse is in your Party.

   • You are in your spouse's Party.

   • You are both in the same Army.

As long as you are together, there is a daily "tick" that rolls for pregnancy. You do not need to wait in a settlement for days; it can happen while travelling on the map.

Fertility & Age

The biggest factor in conception is Age, specifically the mother's age.

• Peak Fertility: Ages 18-25.

• Decline: Fertility starts dropping after 25.

• Cutoff: The hard cutoff for females is typically age 45. After this, pregnancy is impossible.

• Males: Males generally remain fertile much longer, often until death, though chance decreases slightly with extreme age.

Number of Children: The chance of pregnancy drops significantly with each child you already have. The first is easy; the fifth is very rare.

Ensure you start your family early. Waiting until your 30s can limit the number of heirs you produce.

Increasing Your Chances

If you are struggling to conceive, consider these boosts:

1. Virile (Charm Perk): Level 25 Charm perk. Increases chance of having children by 30%.

2. Perfect Health (Medicine Perk): High level Medicine perk. Increases fertility.

3. Beer?: While rumoured, trade goods do not affect fertility in the base game code.

Twins

There is a small, hard-coded chance (around 3-5%) that a pregnancy will result in twins. There are no perks to increase this; it is pure luck.

For what to do once the baby arrives, see our guide on Marriage & Heirs.