According to BabyCentre, the odds of a woman getting pregnant in her mid-40s naturally are less than 5 percent. The likelihood of becoming pregnant, even with a fertility treatment such as in vitro fertilization (IVF), with a female’s own eggs is minimal. Using donor eggs or frozen embryos increases the probability of pregnancy.
According to Fertility Authority, more than 50 percent of IVF cycles with donor eggs result in pregnancy. However, less than 2 percent of females using IVF cycles with their own eggs are able to conceive. The eggs of females in their mid-40s are more likely to have structural abnormalities, making conception more unlikely.
The National Center for Biotechnology Information states that the stillborn rates for women increase 3 to 4 times by the mid-40s. Chromosome abnormalities are nearly 9 percent more likely in a 45-year-old female than in a female in her 20s.
According to BabyCentre, in addition to the decreased odds of becoming pregnant in the mid-40s, the likelihood of the mother developing health problems increases. A woman conceiving in her 40s is twice as likely as a women in her 20s to develop or experience gestational diabetes, high blood pressure and placental abruption (the placenta detaches from the uterus wall). Additionally, the odds are higher for needing a caesarean section, delivering a baby with a low weight and delivering a baby early. The baby is also at an increased risk for developing health issues. Approximately one in 200 babies of women over 40 are born with Down’s syndrome, compared with one in 1,500 for women between 20 and 24.