In the past few decades, there has been a major shift in the pattern of childbirth. More women are opting to get pregnant later in life, due to their careers or late marriage. Although, when to have a baby is completely a personal choice, the fact remains that our reproductive system does not work according to our will, and a woman’s best reproductive years are in her 20s. After that fertility gradually declines in the 30s and particularly after the age of 35. In women younger than 35 the chances of natural conception are 20% per month, thereafter natural conception decreases to 10% after the age of 35 and is only 5% after 40 years of age.
Advances in reproductive sciences have led to increased options for fertility treatment and Assisted Reproductive Technology (ART). Unfortunately, this may give women false optimism that they can delay pregnancy while pursuing their education and careers, with the expectation that ART will help them to conceive if they have difficulty trying to get pregnant later. However, success rates for ART treatment for women using their own eggs are directly linked to the age of the women, and many women may not realize that older women are successful using ART to achieve pregnancy later in life only with donor eggs. ART is also invasive, expensive and not covered by most insurance health plans for this indication. In addition, complications of pregnancy increase for both the mother and the offspring, with advanced maternal age.
The loss of oocytes from the ovaries is a continual process that begins in-utero. At birth, a woman has 1 to 2 million oocytes and only 3,00,000 to 5,00,000 are present at the onset of puberty. This loss of oocytes process continues until menopause, when only a few hundred oocytes remain. As the ovarian follicular pool decreases, women will experience infertility, sterility, cycle shortening, menstrual irregularity, and finally menopause. Once women start to notice clinical signs of ovarian ageing, such as cycle shortening or irregularity, their fertility may already be greatly diminished. Oocyte quality also appears to be affected by age. Studies on IVF oocytes have shown that the rate of oocyte aneuploidy increases with age. The rate is low in women less 35yrs.
Ovarian Reserve Testing
In general, ovarian reserve testing is useful for predicting egg quantity and ovarian response to stimulation but has little value for the prediction of egg quality. Ovarian reserve testing may be considered in women > age 35 to screen for age-related infertility; its results may be useful for women in their decision-making process, regarding treatment options available.
Testing in women < 35 years may be considered if they have risk factors for decreased ovarian reserve, such as a single ovary, previous ovarian surgery, poor response to FSH, previous exposure to chemotherapy or radiation, or unexplained infertility.
Identification of these women may prompt shorter delays in infertility investigations and treatment. The testing includes hormone tests done on day 2 or 3 of the menstrual cycle i.eFSH, estradiol, AMH, and also transvaginal ultrasound for checking the antral follicles. These tests will then be reviewed by the doctor to understand the ovarian reserve of the woman, and accordingly guide her regarding further treatment options.
Associated Medical Problems
Women who have a medical disorder, such as high blood pressure or diabetes, should talk with their doctor before attempting pregnancy. It is important that their health problems are under control. The doctor may suggest a change in medication or general health care before pregnancy, as there are increased risks for older women. Conditions such as high blood pressure or diabetes develop more commonly in women who conceive after age 35. Special monitoring and testing may be recommended during pregnancy, Children born to women over age 35 have a higher risk of chromosomal problems. Women can choose to discuss these risks with their doctor, or a genetic counsellor prior to attempting pregnancy. Prenatal testing may be performed after conception, to check for certain birth defects.
Treatment Of Age-Related Infertility
Fertility treatment for age-related infertility is aimed at increasing monthly fecundity and decreasing the time to conception. Women may be offered controlled ovarian hyperstimulation with clomiphene citrate or gonadotropins and IUI, or IVF to improve their chances of pregnancy and decrease time to pregnancy. Both treatments are intended to increase the number of mature oocytes each month, to balance decreasing oocyte quality, but they do not address the underlying issue of oocyte quantity or quality.
Older women may consider 1 to 2 cycles of IUI if they do not want to try IVF as a first-line treatment, but they should move on to IVF quickly if they are unsuccessful within the first couple of cycles.
Although the chance of success diminishes with age, IVF still offers higher pregnancy and live birth rates than IUI. Oocyte Donation can be considered as a treatment option in case a patient does not conceive with IVF treatment with self-oocytes.
Early Pregnancy and Maternal Complications
Advanced reproductive age is associated with early and later pregnancy complications, in addition to infertility. Age is a recognized risk factor for spontaneous abortion. Pregnancy loss rates after clinical intrauterine pregnancy are 10.4% for women aged < 35 to 16.4% for women aged 35 to 39 and increased to 33% for women aged ≥ 40.
An increased risk of chromosomal abnormalities also occurs with age. Much of the increased risk of early pregnancy loss may be due to the increased rate of chromosomally abnormal conceptions.
Women who wish to delay childbearing until their late 30s or early 40s may consider methods of fertility preservation, such as freezing of embryos after IVF or retrieving and freezing eggs for later use. Ideally this should be done before age 35 years for optimal success.
Preimplantation Genetic Screening
This technology applies to embryos created during a cycle of IVF. It may be particularly useful for older women. With preimplantation genetic screening, a small number of cells are removed from each embryo and genetically evaluated. Embryos for transfer to the mother’s uterus are to be selected from the chromosomally normal embryos. The hope is that this procedure will result in improved successful pregnancy rates, decrease miscarriages and avoidance of transmission of an embryo with a genetic disorder.
Dr. Sunitha Ilinani, Sr. Consultant Fertility Specialist and Laparoscopic Surgeon, Apollo Fertility Centre, Banjara Hills.