Answer: There are at least seven women in the Bible who were initially childless (also referred to as barren). Six of these seven finally did have children after several years. In Old Testament times it was a shame for a wife not to bear children (be childless) for her husband. Although many times it was the female in the marriage who was physically incapable of bearing kids, there were no doubt instances where it was the male who could not engender offspring.
The summary of the benefits and curses of the Law as given to Moses by God shows that if the nation were to be obedient there would not be any childless couples, or even animals, among the people. It also shows that God himself is capable of either shutting up the wombs of women or opening it as he wishes (Exodus 23:26, Deuteronomy 7:14).
The first woman listed as being childless (barren) was Sarai, the wife of Abraham, who was later renamed Sarah. She waited until she was in her nineties before she bore Isaac which means laughter. He was the child of promise and from her barrenness all the nations would be blessed, so in a sense this one child is the beginning of that blessing to all of the nations mentioned in Isaiah 54:1 (see also Galatians 4:27).
The second childless woman mentioned in Scripture was Rebekah. She prayed and then Isaac petitioned God for healing. She finally conceived after twenty years of marriage and had twins sons, Jacob and Esau.
The third barren woman was Rachel, Jacob's beloved wife. Rachel produced two very important sons, Joseph and Benjamin. She lost her life giving birth to Benjamin.
The fourth woman in Scripture who was childless was Samson's mother, the wife of Manoah of the tribe of Dan. She was miraculously healed and bore a son who would become the strongest man who ever lived and a Judge of Israel. Samson was dedicated to be a Nazarite from birth so that he could save God's people from forty years of bondage under the Philistines (Judges 13:1).
The fifth childless woman was the second wife of Elkanah the Ephraimite who was called Hannah. After she prayed that God would heal her womb she gave birth to a boy who would become the prophet Samuel. Samuel was responsible for anointing both Kings Saul and David.
The sixth childless woman in the Bible was the first wife of David, Saul's daughter Michal. She was the prize for the man who could bring down the dreaded Goliath of Gath. She loved David but her father eventually took her out of David's house and annulled the marriage. Scripture seems to indicate that she remained childless the rest of her life.
The seventh of seven Biblically childless women is Elizabeth, the wife of Zacharias, who was barren but in her old age conceived John the Baptist. Jesus called him the greatest man born of a woman.
The firstborn sons of the above females played a vital role in the Bible and in the history of Israel as a nation. The tribes represented by these six sons are Israel and Esau, Joseph, Ephraim, Dan, Levi, Benjamin. When healed, the first child produced by these initially childless women were used to fulfill a special purpose in the plan of God.