2007 ART Report Section 2-ART Cycles Using Fresh, Nondonor Eggs or Embryos (Part B)

A woman’s age not only affects the chance for pregnancy when her own eggs are used, but also affects her risk for miscarriage. Figure 16 shows percentages of ART cycles started in 2007 that resulted in miscarriage for women of different ages. Percentages of ART cycles that resulted in miscarriage were below 14% among women younger than 35. The percentage of ART cycles that resulted in miscarriages began to increase among women in their mid- to late 30s and continued to increase with age, reaching 28% at age 40 and almost 59% among women older than 44.

The risk for miscarriage observed among women undergoing ART procedures using fresh nondonor eggs or embryos appear to be similar to those reported in various studies of other pregnant women in the United States.

A woman’s risk for pregnancy loss (loss of an entire pregnancy, or all fetuses in a multiple-fetus pregnancy) is affected by the duration of her pregnancy and her age. Figure 17 shows that between 13% and 61% of clinically-detected pregnancies (clinical detection through ultrasound performed between 4 and 6 weeks after the day of embryo transfer) are lost at some later point during the pregnancy, depending on the woman’s age. Among women younger than 35, 13% of pregnancies were lost and 87% continued through week 24. In contrast, among women older than 44, 61% of pregnancies were lost and only 39% continued through week 24. In all age groups, most pregnancy losses occurred before week 14 (i.e., during the first trimester). The risk of pregnancy loss after 24 weeks was less than 1% for all age groups because most pregnancies that progress beyond week 24 lead to live births.

In 2007, a total of 101,897 cycles using fresh nondonor eggs or embryos were started:

• 42,127 in women younger than 35
• 23,504 in women 35–37
• 20,612 in women 38–40
• 9,535 in women 41–42
• 4,814 in women 43–44
• 1,305 in women older than 44

Figure 18 shows that a woman’s chance of progressing from the beginning of ART to pregnancy and live birth (using her own eggs) decreases at every stage of ART as her age increases.

• As women get older, the likelihood of a successful response to ovarian stimulation and progression to egg retrieval decreases.
• As women get older, cycles that have progressed to egg retrieval are slightly less likely to reach transfer.
• The percentage of cycles that progress from transfer to pregnancy also decreases as women get older.
• As women get older, cycles that have progressed to pregnancy are less likely to result in a live birth because the risk for miscarriage is greater (see Figure 16).

Overall, 40% of cycles started in 2007 among women younger than 35 resulted in live births. This percentage decreased to 30% among women 35–37 years of age, 21% among women 38–40, 12% among women 41–42, 5% among women 43–44, and 2% among women older than 44.

Figure 19 shows the infertility diagnoses reported among couples who had an ART procedure using fresh nondonor eggs or embryos in 2007. Diagnoses range from one infertility factor in one partner to multiple factors in either one or both partners. However, diagnostic procedures may vary from one clinic to another, so the categorization also may vary.

• Tubal factor means that the woman’s fallopian tubes are blocked or damaged, making it difficult for the egg to be fertilized or for an embryo to travel to the uterus.
• Ovulatory dysfunction means that the ovaries are not producing eggs normally. Such dysfunctions include polycystic ovary syndrome and multiple ovarian cysts.
• Diminished ovarian reserve means that the ability of the ovary to produce eggs is reduced. Reasons include congenital, medical, or surgical causes or advanced age.
• Endometriosis involves the presence of tissue similar to the uterine lining in abnormal locations. This condition can affect both fertilization of the egg and embryo implantation.
• Uterine factor means a structural or functional disorder of the uterus that results in reduced fertility.
• Male factor refers to a low sperm count or problems with sperm function that make it difficult for a sperm to fertilize an egg under normal conditions.
• Other causes of infertility include immunological problems, chromosomal abnormalities, cancer chemotherapy, and serious illnesses.
• Unexplained cause means that no cause of infertility was found in either the woman or the man.
• Multiple factors, female only, means that more than one female cause was diagnosed.
• Multiple factors, female and male, means that one or more female causes and male factor infertility were diagnosed.

Figure 20 shows the percentage of ART cycles that resulted in live births according to the causes of infertility. (See Figure 19, or the Glossary in Appendix B for an explanation of the diagnoses.) Although the national average was about 29% (see Figure 7), the percentage of ART cycles that resulted in live births varied somewhat depending on the couple’s diagnosis. In 2007, the percentage of ART cycles resulting in live births was higher than the national average for couples diagnosed with tubal factor, ovulatory dysfunction, endometriosis, male factor, or unexplained infertility; it was lower for couples diagnosed with uterine factor, “other” causes, multiple infertility factors, or diminished ovarian reserve. Please note, however, the definitions of infertility diagnoses may vary from clinic to clinic and that a review of select clinical records revealed that reporting of infertility causes may be incomplete. (See Findings from Validation Visits for 2007 ART Data in Appendix A for additional information.) Therefore, differences in success rates by causes of infertility should be interpreted with caution.

Figure 21 shows the number of previous births among women who had an ART procedure using fresh nondonor eggs or embryos in 2007. Most of these women (71%) had no previous births, although they may have had a pregnancy that resulted in a miscarriage or an induced abortion. About 21% of women using ART in 2007 reported one previous birth, and about 8% reported two or more previous births. However, we do not have information about how many of these were ART births and how many were not. These data nonetheless point out that women who have previously had children can still face infertility problems.

Figure 22 shows the relationship between the success of an ART cycle and the woman’s history of previous births. Previous live-born infants were conceived naturally in some cases and through ART in others. In all age groups, women who had a previous live birth were more likely to have a successful ART procedure.

In 2007, 72,337 ART cycles were performed among women who had not previously given birth. However, about 27% of those cycles were reported by women with one or more previous pregnancies that had ended in miscarriage—we do not have information on whether these pregnancies ending in miscarriage were the result of ART or were conceived naturally. Figure 23 shows the relationship between the success of an ART cycle and the history of previous miscarriage. In all age groups, women who had a previous miscarriage were about as likely to have a live birth as women who had never been pregnant. Thus, a history of unsuccessful pregnancy does not appear to be associated with lower chances for success during ART.

Figure 24 presents ART cycles that used fresh nondonor eggs or embryos in 2007 according to whether previous ART cycles had been performed. For about 40%, one or more previous cycles were reported. (This percentage includes previous cycles using either fresh or frozen embryos.) This finding illustrates that it is not uncommon for women to undergo multiple ART cycles. We do not have information on when previous cycles were performed, nor do we have information on the outcomes of those previous cycles.

Figure 25 shows the relationship between the success of ART cycles performed in 2007 using fresh nondonor eggs or embryos and a history of previous ART cycles among women with no previous births. In all age groups, percentages of ART cycles that resulted in live births were lower for women who had previously undergone an unsuccessful ART cycle.

Figure 26 shows the relationship between the success of ART cycles performed in 2007 using fresh nondonor eggs or embryos and a history of both previous ART cycles and previous births. We do not have information on whether the previous births were the result of ART or were conceived naturally. However, among women with previous births, percentages of ART cycles that resulted in live births among women who did not undergo a previous ART procedure were comparable to percentages among women who had undergone previous ART cycles, except for women with advanced age over 44.

Although Figure 25 shows that having undergone previous ART cycles may be related to the success of the current ART cycle, it is also important to consider the outcomes of previous cycles and whether the woman has given birth in the past, as demonstrated in this figure.