Pregnancy at advanced maternal age (AMA), defined as age 35 years or older, is associated with adverse reproductive effects such as increased risk of infertility, and that the children have chromosomal abnormalities. The corresponding paternal age effect is less pronounced.
In present generations it is more common to have children at an older age. Several factors may influence the decisions of parents when having their first baby. Such factors include educational, social and economic status.
Although chronological age (from birth to a given date) is the most important predictor of ovarian response to follicle-stimulating hormone (FSH), the rate of reproductive ageing varies considerably among individuals. Both environmental and genetic factors contribute to biological ovarian ageing. Thus, chronological and biological age (influenced by many lifestyle factors into consideration, including diet, exercise and sleeping habits) are not always equivalent because chronological age does not change, regardless of how healthy a lifestyle etc. Furthermore, biological age is more important than chronological age in predicting the outcome of assisted reproductive technology (ART). Moreover, independent of chronological age, ovarian ageing affects both oocyte fecundity and quality and can negatively impact on the outcome of ART.
Advanced maternal age could have several effects:
Several studies have shown an association between AMA and adverse perinatal outcomes as well as an increased risk of certain pregnancy complications. Specifically, women of AMA have an increased risk of gestational diabetes, placenta previa (placenta lies in the uterus and covers the cervix), preeclampsia (high blood pressure and protein in your urine during pregnancy), miscarriage, pregnancy-induced hypertension and the need for Caesarean deliveries. Induction of labor, augmentation with oxytocin and assisted deliveries are also known to be associated with women of AMA. Furthermore, increasing maternal age contributes to fetal, perinatal and neonatal death. Women of AMA are also more likely to have been diagnosed with chronic diseases, such as hypertensive disorders and diabetes mellitus, thus further complicating their pregnancies.
Many reports have suggested that advanced maternal age is an important factor related to chromosomal aneuploidies. Aneuploidy is a state in which cells have an abnormal and unbalanced number of chromosomes, for example triple chromosome 21 in Down syndrome. Hormonal changes during the aging process, as decreased production of progesterone can lead to increased rates of miscarriage in women older than 35 years.
On the other hand, advanced maternal age is associated with a more stable family environment, higher socio-economic position, higher income and better living conditions, as well as better parenting practices, but it is more or less uncertain whether these entities are effects of advanced maternal age, are contributors to advanced maternal age, or common effects of a certain state such as personality type.
Advanced maternal age is often linked to high blood pressure (hypertension) and diabetes that can affect pregnancy. Factors like poor diet, stressful life style, alcohol consumption, smoking, lack of minerals, vitamins and antioxidants all contribute to poor egg quality.
A more detailed prenatal ultrasound is recommended in order to determine how baby is growing and if any abnormalities are present. There are also a number of prenatal tests that will be offered if women are over 35 and pregnant.
A woman over age 35 should consult her doctor if she has not conceived after six months of trying.
A woman's fertility peaks lasts during the twenties and first half of thirties, after which it starts to decline, with advanced maternal age causing an increased risk of female infertility (Pic. 2).
As women age, they experience a decline in reproductive performance leading to menopause. This decline is tied to a decline in the number of ovarian follicles (ovarian reserve; Pic. 3). Although about 1 million oocytes are present at birth in the human ovary, only about 500 (about 0.05%) of these ovulate, and the rest do not (ovarian follicle atresia). The decline in ovarian reserve appears to occur at a constantly increasing rate with age, and leads to nearly complete exhaustion of the reserve by about age 51.
A typical woman has 12% of her reserve at age 30 and has only 3% at age 40. 81% of variation in ovarian reserve is due to age alone, making age the most important factor in female infertility. As ovarian reserve and fertility decline with age, there is also a parallel increase in pregnancy failure and meiotic errors resulting in chromosomally abnormal conceptions.
Pregnancy at age 35 years or older within a healthy context and in the absence of other risk factors is perceived as a low risk pregnancy. However, in the presence of risk factors such as pregnancy complications, limited physical activity, unfavorable screening tests results, previous poor reproductive history, and anxiety, the risk associated with age is highlighted, and women are inclined to recognize their age as a risk factor for their pregnancy.