A monthly nurse is a woman who looks after a mother and her baby during the postpartum or postnatal period. The phrase is now largely obsolete, but the role is still performed under other names and conditions worldwide.

In the past, it was customary for women to rest in bed or at home for a prolonged period after childbirth. Typically, their female relatives, such as their mother or mother-in-law, would provide care. Alternatively, wealthy families would sometimes hire a monthly nurse. This period, known as confinement or lying-in, would end with the mother's reintroduction to the community during a Christian ceremony called the churching of women. In 18th and 19th century England, the term "monthly nurse" was prevalent since the nurse would usually stay with the patient for four weeks. However, the term "monthly" is not entirely accurate since there was no fixed time or date for the nurse's services to be provided or to end, but rather it was entirely dependent on the arrangement.

The occupation still exists, although now it might be described as "postnatal doula", "maternity nurse" or "newborn care specialist", all are specialist sorts of nannies. A modern version of this rest period has evolved to give maximum support to the new mother, especially if she is recovering from a difficult labor and delivery. It is common in China and its diaspora, where postpartum confinement is known as "sitting the month". These workers can visit the new mother's home daily or live in it for a month and look after them whenever the mother needs help. Conversely, they may work in a central setting, where the new mothers come after they leave the hospital. In Korea, these workers are called Sanhujorisa, and the centers started up in the late 1990s.

Historically, midwifery was a skill passed down through generations within families, with the daughter learning from her mother and gaining hands-on experience before becoming a midwife herself. The Church of England supported that by a system of episcopal licensing, which required midwives to swear to some rules regarding contraception, abortion, and concealment of births and also to deliver the newborn infants for baptism or, in extreme cases, to perform the ceremony themselves. However the system of episcopal licensing fell into decline over the latter part of the 17th century, ceasing to exist in London by 1720 and not much later in other areas.

It is unclear exactly when the monthly nurse appeared as an entity. Humfrey commentating in 1891 cites an interplay of factors arising during the 17th and 18th centuries with the advent of instrumentation being used in childbirth and the emergence of "man-midwives". Lying-in hospitals were established in the 18th century and during the 18th/19th centuries the process of childbirth became more medicalised. Much of childbirth remained midwife led but the medical profession was becoming more involved with the surgeon's responsibility being vested around the immediate childbirth process. This raised the question of who would take care of the baby after birth whereas hitherto the roles of nurse and midwife were combined in one person. It was generally thought that the best person to look after her baby was a woman who had had one herself. Often, the task was allotted to motherly or grandmotherly hands, and the "monthly nurse" originated from that requirement for postnatal care. Humfrey writing in The Nursing Record in 1901 reported that "there was little or no attempt at knowledge or instruction, and we know as a fact that ignorance, prejudice and neglect resulted in a goodly crop of errors, wrongs, and woes as regards the hapless infant".

The Nursing Record reported that "nurses who attend the 'artisan' classes in their confinements as a rule pay a visit daily for ten days and then give up the case, as few working class mothers can afford to lie up for longer".

A monthly nurse could earn more than a midwife, as the monthly nurse was employed for periods between 10 days and often much longer and might attend to several women part-time. She often "lived in". The midwife's only duty was perceived as "being trained to assist the parturient  woman while nature does her own work and able to call upon a surgeon who could step in where nature fails and skill and science are required". Many certified midwives transferred to the ranks of monthly nurses to benefit from an increased income.

Although 'registration' was not available for women to act as midwives or monthly nurses, a system of 'certification' existed in the late 19th century and continued into the early 20th century. To qualify, a candidate monthly nurse would attend a course in a lying-in hospital for four or five weeks and a midwife's office for up to three months. They were not financially supported by the hospital and had to bear their own expenses, but they were also given the freedom to practice independently once they completed their training. In 1893, Miss Gosling reported that "although the certificated monthly nurse could be relied upon as being trustworthy and efficient, there were a number of women who attend lectures for a short time and through one cause or another failed to pass their examination and obtain a certificate nevertheless enter a 'Nurses Home' or open one for themselves". Miss Gosling alludes to difficulty of the public not asking to see certification. She also advocates Registration for Monthly Nurses.