Assisted Reproduction and Delayed Childbearing
Many women who plan to have a child in the late 30s and early 40s are likely to face infertility issues and then turn to assisted reproduction. This trend is partially fueled by widespread misconceptions about the ability of assisted reproduction to compensate for infertility in later periods of reproductive age that gives women the illusion of controlling fertility in the higher reproductive ages. Despite the fact, that many rich countries do not subsidize assisted reproduction for women after a certain age period, the number of ART cycles increases most rapidly at age 40+.
In the United States, women aged 40+ initiated 21% of all ART cycles in 2013. In Europe, the number of registered ART cycles at age 40+ increased much faster in 2002-2012, 3.1 times than the number of ART cycles initiated by younger women, which increased 1.8-fold. Especially, sharp growth was achieved for ART cycles using donated oocytes, which quadrupled over the same period. In general, the proportion of ART cycles initiated by women aged 40+ in 2002-2012 increased from 12 to 19%, representing about 7% of all children born to women older than age 40+.
The success rates of non-donor ART cycles are measured, in particular, by the percentage of ART cycles that lead to pregnancy, live births or single-infant live births, rapidly decline with age among women under age 32. Among women undergoing ART cycles until 2013, the pregnancy rate per ART cycle reached 46% at age 35, 25% at age 40, and only 4% at age 45+. Because of high rates of miscarriage in the higher age groups, the fall in the likelihood of live birth following ART cycle is even steeper with age. Thus, 40% of ART cycles not associated with donors started at age 35 led to the live birth in 2013 compared with 17% of cycles started at age 40 and 2% at age 45+. The probability of a live birth improved only gradually among women aged 40. Most women do not reach pregnancy, which leads to birth after age 40, even after six or more consequent ART cycles.
Thus, traditional ART cycles using non-donor oocytes cannot compensate age-related fertility decline, and for many women it does not give a realistic chance of having a child after age 40. In addition, the cost of assisted reproduction treatment per live birth delivery grows dramatically after age 40, making traditional non-donor ART cycles use problematic, especially after age 45.
In contrast, ART with donor oocytes demonstrates a surprisingly stable success rate with age of women treated, with a percentage of ART cycles resulting in live birth staying over 50% even for women aged 40, according to the United States data for 2013. Therefore, despite the higher costs and despite the fact that in case of successful treatment the child will not be genetically linked to the mother, the use of donor oocytes is rapidly increasing. In the United States, donor oocytes accounted for 37% of ART cycles among women aged 41+ and about 78% of live births among assisted reproduction users of this age; for Europe, the corresponding estimates were 17% and 41%, respectively.
In the United States, the number of oocyte or embryo cycles has increased from about 1,000 in 2006 to more than 27,000 in 2013. Surprisingly, 30% of these freezing cycles, occur at ages 41+, i.e., when the quality of oocytes deteriorates rapidly, implying lower chances of successful pregnancy and childbirth later in life.
Contrasting Biological and Social Grounds for and Against Late Parenting
As longevity continues to grow, life courses of men and women stretch, and they experience many important transitions later in life. They complete their education, move from parental home, enter the labor market or retire to ever-higher ages. The rapid increase in the number of women who do not have children at age 35 but who plan to have a child in the future is perfectly in line with this trend.
With some simplification, children born to older parents are also born to more stable, happier and wealthy families. Many social and economic considerations suggest for having children late in life. Nevertheless, these arguments clash with “uncomfortable biology”, because there is also a clear biological and health justification for having children much earlier in life. The sharp increase in the number of assisted reproduction treatments at later reproductive ages illustrates the extent of infertility and unmet need for pregnancy among women who may have postponed parenting for too long.
The emergence of assisted reproduction treatments with donor oocytes and the achievements in “social egg freezing” have gradually undermined the biological fertility limits marked by follicular depletion and menopause. The number of postmenopausal women who become pregnant is growing fast, although from very low numbers. At the same time, a vast majority of women still plan to become pregnant without the help of assisted reproduction.
They often fall between the conflicting motives for and against having children and struggling with an increasingly urgent question: “How long can I wait to have a child?” The answer depends on family size preferences and the strength of these preferences.
Leave a ReplyWant to join the discussion?
Feel free to contribute!