nulliparity, para 0, gravida 0, childlessness
Never given birth is the term used in a woman who has never carried a pregnancy beyond 20 weeks Those women are nulliparous, and is called a nullipara or para 0. Terms such as "gravida 0", referring to a nulligravida, "gravida 1" for a primigravida, and so on, can also be used. The term "elderly primigravida" has also been used to refer to a woman in her first pregnancy, who is at least 35 years old.
Never giving birth during lifetime is associated with exposing to high levels of hormones for longer periods of time that increases the risk cancers of reproductive organs.
Types of childlessness can be classified into several categories:
Natural sterility randomly affects individuals. One can think of it as the minimum level of permanent childlessness that we can observe in any given society, and is of the order of 2 percent.
Social sterility which one can also call poverty driven childlessness, or endogenous sterility (sterility by manipulating endogenous hormone levels), describes the situation of poor women whose fecundity has been affected by poor living conditions.
People who are childless by circumstance.
These people can be childless because they have not met a partner with whom they would like to have children, or because they tried unsuccessfully to conceive at an advanced maternal age, or because they suffer from certain medical issues, such as endometriosis or polycystic ovary syndrome (PCOS), that make it difficult for them to conceive.
People who are childless by choice
Many of these are educated and tend to postpone marriage to invest more in their career, or have a very high opportunity cost to bear and rear a child, often in terms of foregone labour income.
The first three categories are often grouped under the label "involuntary childlessness". The latter category is often called "voluntary childlessness", also described as being "childfree", occurring when one decides not to reproduce.
Medical interventions may be available to some individuals or couples to treat involuntary childlessness. Some options include artificial insemination, intracytoplasmic sperm injection (ICIS) and in vitro fertilization (IVF).
For those facing social infertility (such as single individuals or same-sex couples) as well as heterosexual couples with medical infertility, other options include surrogacy and adoption. Surrogacy, in this case a surrogate mother, is the process in which a woman becomes pregnant (usually by artificial insemination or surgical implantation of a fertilized egg) for the purpose of carrying the fetus to term for another individual or couple. Another option may be adoption; to adopt is to take voluntarily (a child of other parents) as one's own child.
Delaying the first childbirth to an advanced age has increased significantly during the last decades. Pregnancy at advanced maternal age, defined as age 35 years or older, is associated with several adverse pregnancy outcomes including preterm birth, low birth weight, still birth, chromosomal defects, labor complications, and cesarean section; therefore, it is considered to be a “high risk” pregnancy.
An increased risk cancer of reproductive organs has been found due to nulliparity. In most studies, the risk of uterine cancer decreases with increasing parity, especially among women in reproductive years. Several recent studies have shown that past births at the end of reproductive life may reduce the risk of uterine cancer.
A uterine cancer is associated with prolonged exposure to estrogen (female sex hormone) and pregnancy provides a period of endometrial “rest”. Also the women who take birth control pills for at least five years during her reproductive years are at reduced likelihood of developing the disease. Women who have also been to get pregnant are at lower risk of getting ovarian cancer than women who have never given birth.
Prolonged nulliparity is a risk factor for breast cancer. Pregnancy may reduce breast cancer risk through induction of persistent changes of the mammary gland that make the breast less susceptible to carcinogenic factors.
The only possible prevention of nulliparity is to become pregnant. On the other side, oral contraceptives have been shown to reduce the risk for ovarian cancer but it could increase the risk of breast cancer.
Mechanisms of nulliparity that can mediate the risks associated with infertility include:
Anovulatory menstrual cycles
Higher serum levels of estrogen may lead to infrequent or anovulation which consequently reduces progesterone protection of the endometrium (uterine lining) from high levels of unopposed endogenous (natural) estrogen. An absence of childbearing results in a prolonged exposure of estrogen without sufficient progesterone (the hormone of pregnancy). In anovulation, ovaries do not release an egg and the ovulation does not take place.
Elevated levels of androstenedione
Androstenedione is a precursor of testosterone and other androgens (male sex hormones), as well as of estrogens like estrone, in the body. Androstenedione is converted into estrogens, reduces the clearance (volume of plasma from which a substance is completely removed per unit time) of estrogen from the blood. This results in continuous exposure of the endometrium to high levels of estrogen. Elevated androstenedione levels can cause symptoms or signs of hyperandrogenism (elevated levels of androgens) in women.
The most common conditions associated with hyperandrogenism are polycystic ovary syndrome or PCOS, a set of symptoms caused by androgen excess in females, and various cancers that can cause androgen excess. In females, the conditions usually present are some combination of acne, seborrhea (inflamed skin), hair loss on the scalp, increased body and/or facial hair (hirsutism), and an elevated sex drive or libido.
The lack of monthly sloughing of the lining of the endometrium
The lack of monthly sloughing of the lining of the endometrium could result in the excessive proliferation of the cells of the residual endometrial tissue (endometrial hyperplasia).
Most cases of endometrial hyperplasia result from high levels of estrogens, combined with insufficient levels of the progesterone-like hormones which ordinarily counteract estrogen's proliferative effects on this tissue.
Gynecologic cancers include vulva, vaginal, cervical, endometrial, and ovarian/tubal/peritoneal cancers, the latter of which are still classified as one disease. These patients face difficulty conceiving secondary to obesity, polycystic ovarian syndrome and chronic anovulation. Secondary to these issues it is recommended an initial consultation with a reproductive endocrinologist in order to assess the patient’s reproductive options and likelihood of conception. This ensures appropriately informed expectations regarding reproductive potential and thus the patient’s desire to proceed with fertility-preserving therapy.
Several studies have investigated the influence of childlessness on the psychological well-being of middle-aged and elderly individuals using a wide range of outcome measures. In these studies, it was not specified whether the participants were voluntarily or involuntarily childless. A majority of the studies found that being childless does not significantly influence the psychological well-being of elderly individuals. Childless middle-aged and elderly individuals do not appear to be lonelier, unhappier or more depressed and are not less satisfied with their lives than those who are parents.
The results of some studies indicate that marriage decreases the frequency of occurrence of depressive symptoms, loneliness and increases the satisfaction with life among elderly men and women. Other studies have not found any differences between married and never-married men and women regarding depression, happiness, loneliness or life satisfaction.
Women without children have also been found to have an increased risk of breast cancer, and increased mortality from uterine, ovarian and cervical cancer when compared to women with children. Moreover, the fertility declines with the advanced age at first childbearing.