(LifeWire) - Most women know that fertility gradually diminishes as they age, but they may not know exactly how long they will be capable of conceiving -- whether they want to or not.
“They don’t call them ‘change of life babies’ for nothing,” says Cynthia Stuenkel, M.D., clinical professor of medicine at the University of California, San Diego. Stuenkel, a menopause expert, emphatically answers yes to this speculation of women at midlife.
According to the National Center for Health Statistics, about 111,000 American women between the ages of 40 to 54 gave birth in 2005, the latest year for which figures are available. About 6,500 of them were over 45, when many erroneously assume naturally-conceived pregnancy is no longer possible. Moreover, half of pregnancies in women over 40 are unintended.
Many other questions surround the biological transition from child-bearing years to post-menopause, including:
Q: What is perimenopause?
A: Perimenopause refers to the months or years leading up to menopause, which is the permanent cessation of menstrual periods and occurs at an average age of 51. This stage can last just a few months or for up to eight years, beginning as early as a woman’s late thirties. Periods tend to become irregular during perimenopause, and women often experience hot flashes, mood swings, vaginal dryness, fatigue or difficulty sleeping.
Doctors can perform a variety of blood tests to determine if a woman who has skipped one or more periods is either pregnant or beginning perimenopause. These tests measure the levels of certain hormones, some of which signal pregnancy and others that predict ovarian function or decline.
Q: How will I know if I’m still fertile?
A: You must assume you are still capable of conceiving until menopause is complete, which has not occurred until menstrual periods have ceased for 12 full months. “Menopause is not an on-off switch,” says Stuenkel. “But many women don’t really understand exactly what’s happening.”
Ovarian function waxes and wanes in perimenopause, meaning that a woman may release an egg some months but not others. Additionally, body levels of estrogen, progesterone and other hormones tend to be erratic during this time and egg quality decreases, all contributing to a 50% decrease in fertility among women 40 and over compared to younger women. But natural conception is still possible -- if remote -- for women until their mid-fifties.
Q: Do I still need contraception?
A: Yes. Unless you want to conceive during perimenopause, contraception is essential until you haven’t had a period for a full year. But the query is a common one. A 2007 study of perimenopausal contraception among Turkish women in BMC Nursing found that while 87% of participants were sexually active, the vast majority of them had no idea when they should abandon contraception use. “If you really want to be sure,” Stuenkel says, “it would be best to continue.”
Q: What are the risks of pregnancy during perimenopause?
A: The possible hazards are many to both mother and baby. Miscarriage, which normally occurs in about one of three pregnancies, increases among older mothers because of lower-quality eggs, variable hormones and uterine changes. Poor egg quality also ups the chances for birth defects such as Down syndrome, which is caused by an error in cell division which produces an extra chromosome. Other risks to the baby include premature birth (anytime before 37 weeks of gestation), which is linked to a host of complications ranging from cerebral palsy to learning and developmental disabilities.
The rigors of pregnancy are also harder on older mothers, who suffer more than their younger counterparts from complications such as high blood pressure, strokes, seizures, gestational diabetes and heart problems.
These women “are going to be considered higher risk and they may or may not have a genetic evaluation” by their doctors, Stuenkel says.
Q: What if I’m in perimenopause and still want to have a baby?
A: Act quickly. Beyond that, consult your doctor if you haven’t conceived after six months of unprotected intercourse (one year is the recommendation for younger women). Hormone therapy, assisted reproduction or egg donation are all possibilities to help older women conceive.
"An Introduction to Menopause." nih.gov. 31 Jul. 2008. National Institutes of Health. 11 Aug 2008 <http://www.nia.nih.gov/HealthInformation/Publications/Menopause/int>.
"Demographic Characteristics of Mother -- 2005." cdc.gov. National Center for Health Statistics. 11 Aug 2008 <http://22.214.171.124/VitalStats/TableViewer/tableView.aspx?ReportI>.
Gindof, Paul R.. "Fertility Management in the Older Woman." resolve.org. 2008. Resolve: The National Infertility Association. 11 Aug 2008 <http://www.resolve.org/site/PageServer?pagename=pubs_fmow>.
Sahin, Nevin H. and Kharbouch, Sema B.. "Perimenopausal Contraception in Turkish Women: A Cross-Sectional Study." BMC Nursing 6:18 Mar. 2007. 1472-6955. 11 Aug 2008 <http://www.biomedcentral.com/1472-6955/6/1>.
Stuenkel, Cynthia. Telephone interview, 5 August 2008.
"What is Perimenopause?." clevelandclinic.org. 6 Dec. 2006. Cleveland Clinic. 11 Aug 2008 <http://my.clevelandclinic.org/disorders/Menopause/hic_What_is_Peri>.