If God's ancient laws are to be believed there is/was a solution for that.
Deuteronomy 7:12-14 King James Version (KJV)
12 "Wherefore it shall come to pass, if ye hearken to these judgments, and keep, and do them, that the Lord thy God shall keep unto thee the covenant and the mercy which he sware unto thy fathers:
13 And he will love thee, and bless thee, and multiply thee: he will also bless the fruit of thy womb, and the fruit of thy land, thy corn, and thy wine, and thine oil, the increase of thy kine, and the flocks of thy sheep, in the land which he sware unto thy fathers to give thee.
14 Thou shalt be blessed above all people: there shall not be male or female barren among you, or among your cattle."
Even during their captivity/sojourning in Egypt the Israelite women were very fecund, with easier childbirths than the Egyptian women. It might be well for our women to copy their vigorous, physical lifestyle.
Exodus 1:19-20 King James Version (KJV)
19 "And the midwives said unto Pharaoh, Because the Hebrew women are not as the Egyptian women; for they are lively, and are delivered ere the midwives come in unto them.
20 Therefore God dealt well with the midwives: and the people multiplied, and waxed very mighty."