As far as Islamic Shari`ah is concerned, Islam encourages having children. However, it allows Muslim spouses to have space between pregnancies and to plan their family in order to provide their children with proper nurturing and care and not to violate their right to breastfeeding for a reasonable period.

Sheikh Muhammad Nur Abdullah, former President of the ISNA (Islamic Society of North America) and member of the Fiqh Council of North America, states: I do not recall an ayah (verse) from the Qur’an or a hadith from the Sunnah that speaks directly about this. The whole matter, in my opinion, revolves around the maslahah (public interest), or what would be in the best interest of the family, especially the mother. If the mother would like to take some rest so that she can be physically and emotionally capable of raising the second or the third child, then definitely she can do so.
Some quote the ayah stating that (the mothers shall breastfeed their children for two whole years, if they desire to complete the term) (Al-Baqarah 2:233) as a basis for the baby’s right to breastfeeding, and if it will be affected by pregnancy, then it is as if infringing upon the right of the baby. This ayah could serve as a supporting evidence for getting a rest between each child and another until the first gets breastfed for a reasonable time.