Getting pregnant at age 40 is possible, a reality supported by rising birth rates in this age group. However, conception is associated with a reduced chance of natural pregnancy and an increased likelihood of certain health risks for both mother and baby. Understanding these factors allows for informed decision-making and proactive medical planning.
Understanding Fertility Changes
Fertility declines around age 40, largely due to changes in a woman’s ovarian reserve. Ovarian reserve refers to the finite quantity of eggs remaining in the ovaries. Unlike men who produce new sperm continuously, women are born with all the eggs they will ever have, and this number decreases naturally over time.
Beyond the decline in quantity, the quality of the remaining eggs also decreases with age. This decline is characterized by an increased incidence of chromosomal abnormalities, known as aneuploidy. By age 40, only about 10 to 15 percent of a woman’s eggs are estimated to be chromosomally normal, compared to around 70 percent in her mid-30s.
The combined effect of reduced quantity and quality means the probability of conception during any single menstrual cycle is lower. A woman in her early 20s has approximately a 25 percent chance of getting pregnant per cycle, but this drops to about a 5 to 10 percent chance by age 40. This makes natural conception take longer in the early forties.
Potential Health and Pregnancy Risks
Pregnancy at age 40 or older is classified as advanced maternal age, which carries an elevated risk for specific health complications. For the mother, there is an increased risk of developing hypertensive disorders, including gestational hypertension and preeclampsia, a serious condition involving high blood pressure and organ damage.
The risk of developing gestational diabetes is also higher, with rates in women aged 40 and over being more than double those in women aged 25–35. Older age is independently associated with a greater likelihood of requiring a Cesarean section delivery, often due to complications like placenta previa or fetal distress.
The fetus also faces increased risks, primarily related to the higher rate of chromosomal abnormalities in the egg. The risk of miscarriage rises, with some data suggesting the rate is around 34 percent for women aged 40–44.
Chromosomal conditions like Down syndrome (Trisomy 21) become more common, with the risk rising from approximately 1 in 1,480 at age 20 to about 1 in 85 at age 40. There are also increased risks for adverse outcomes such as preterm birth and stillbirth. Prenatal testing, such as genetic screening, is an important consideration for this age group to assess these risks and necessitates closer monitoring throughout the pregnancy.
Medical Paths to Parenthood
Given the decline in fertility after age 40, medical professionals recommend seeking a fertility assessment sooner than for younger women. If a woman over 40 has been trying to conceive for six months without success, consulting a specialist is advised. An initial workup typically involves blood tests, such as measuring Anti-Müllerian Hormone (AMH) and Follicle-Stimulating Hormone (FSH), to evaluate the remaining ovarian reserve.
Assisted Reproductive Technologies (ART), particularly In Vitro Fertilization (IVF), are often the next step. IVF involves stimulating the ovaries to produce multiple eggs, retrieving them, and fertilizing them in a lab. While the success rate of IVF using a woman’s own eggs declines with age due to egg quality, a single cycle can still offer a chance of pregnancy.
When egg quality or ovarian reserve is diminished, the use of donor eggs from a younger woman is often a more successful path. Using donor eggs increases the chance of a successful pregnancy and lowers the risk of miscarriage, as success is tied to the age of the egg, not the recipient. Preimplantation genetic testing (PGT) can also be used with IVF to screen embryos for chromosomal abnormalities before transfer, which reduces miscarriage rates.