Because The Sims 3 is an older engine, conflicts can happen. If you encounter bugs, check the following solutions:
[ Mother Sim ] [ Baby / Toddler ] │ │ ▼ ▼ ┌───────────────────────┐ ┌───────────────────────┐ │ Custom Nursing Buff │ │ "Peaceful Baby" Buff │ │ (Boosts Happiness) │ │ (Lasts For 2 Hours) │ └───────────┬───────────┘ └───────────┬───────────┘ │ │ └───────────────┬────────────────────┘ ▼ ┌─────────────────────────┐ │ Long-Term Relationship │ │ Gain (+15 LTR Points) │ └─────────────────────────┘ sims 3 breastfeeding mod
This mod is stable but not perfect. Here is the compatibility matrix: Because The Sims 3 is an older engine, conflicts can happen