As women marry later and later in the developed world, and many plan both a family and a career, the age at which a first pregnancy occurs is increasing, sometimes to beyond 40 years old. Childbirths are spaced at accommodate a career, so the last pregnancy also is much later.
When a woman gets much beyond 50, virtually all the serious complications of pregnancy are much more likely. High blood pressure, toxaemia of pregnancy, heart disease, diabetes, and thrombosis are all relatively probable and she is less likely to have the strength to care for her new-born in the event of its safe delivery. There is also a significant chance that she may lose the baby at any time during pregnancy. Older women are more likely to have multiple births, as their chance increases with age of releasing two or more eggs at once.
Older women who have not been able to conceive before are particularly vulnerable to suffer extraordinary psychological trauma from such a loss. For those who have become pregnant artificially (by in vitro fertilization with a donated egg), clinical experience often shows that they have found themselves unable to come to terms with their menopause and the cessation of their ability to reproduce. They are, in effect, undergoing a process of bereavement which becomes protracted if they are inappropriately treated.
In 1993, a 53-year-old UK woman was expecting a twin pregnancy as a result of in vitro fertilization treatment in Italy following egg donation. In 1997, a 63 year old woman gave birth similarly.
Babies born to older mothers tend to have significantly higher than usual blood pressure, which may affect the working of their hearts and arteries throughout their lives. Researchers at Harvard Medical School found that for every five-year increase in a mother's age, there is a 1.5-point increase in her newborn's blood pressure. The baby of a 40-year-old woman will have systolic blood pressure - the higher of the two numbers - that averages five or six points higher than a child born of a 20 year old.
A woman who goes to the enormous trouble of having a baby by these artificial methods at considerable risk to her own health truly wants a child, and will be a good mother.
It suits the state, the media and some pioneering doctors to promote the idea of "miracle babies" and to push the age of childbearing ever further back, but it suits the child to have young parents -- and preferably one of each sex, living happily together ever after. That is the true "miracle baby" nowadays but, like all miracles, it is increasingly rare.