BismilLahir Rahmaanir Raheem.
The institution of marriage and the want to have children was the custom of the best of creation, the prophets and messengers chosen by ALLAH. ALLAH says about them
"And indeed ALLAH sent messengers before you and made for them wives and offspring" (al-Raad 38).
The best example for the believers is the example of the prophet Muhammad (sallallaahu alaihi wasallam), who married and had children. These prophets and messengers are the people whom Muslims should look to emulate. Allah says
"They are those whom ALLAH has guided. So follow their guidance" (al-Anaam 90).
They should be emulated and none else.
Islam has forbidden celibacy (state of not being married), monasticism (life of monks & nuns) and castration (removal of the male glands) for such purposes. The prophet (sallallaahu alaihi wasallam) made this clear when he told those companions who were considering acetic forms of life: "I pray and I sleep; I fast and I break my fast; and I marry women. Whoever turns away from my way of life is not from me."
The prophet (sallallahu alaihi wasallam) not only encouraged marriage but he encouraged marrying those women who are child-bearing. He stated: "marry the loving, child-bearing women for I shall have the largest numbers among the prophets on the day of Resurrection."(Recorded by Ahmad and ibn Hibban.).
From the Islamic perspective, children are a gift and a blessing from ALLAH. ALLAH mentions some of the bounties that HE has bestowed upon mankind in the following verse: "And ALLAH has made for you spouses of your own kind and has made for you, from your wives, sons and grandsons, and has bestowed upon you good provisions." (al-Nahl 72).
ALLAH also said: "Wealth and children are the adornment of the life of this world." (al-Kahf 46).
The only true provider for all mankind is ALLAH. If Muslims follow what ALLAH has prescribed for them, ALLAH will provide for them. ALLAH has warned about killing one's children out of fear of poverty for either parents or the child. ALLAH says: "Kill not your children because of poverty - ALLAH provide sustenance for you and for them" (al-Anaam 151).
ALLAH also says: "And kill not your children for fear of poverty. ALLAH shall provide for them as well as for you. Surely, the killing of them is a great sin" (al-Isra 31).
Hence, Muslims should never abort or kill their children out of fear of poverty. It is ALLAH who provides for them.
To be continued in Shaa ALLAH. Please hold on to your questions on this topic till after the third Reminder to understand the topic well. May ALLAH keep guiding us all and grant us Halaal form of sustenance. Aameen.