The status of preimplantation genetic testing in the UK and USA

Abstract

Study question: Has the number of preimplantation genetic testing (PGT) cycles in the UK and USA changed between 2014 and 2016?

Summary answer: From 2014 to 2016, the number of PGT cycles in the UK has remained the same at just under 2% but in the USA has increased from 13% to 27%.

What is known already: PGT was introduced as a treatment option for couples at risk of transmitting a known genetic or chromosomal abnormality to their child. This technology has also been applied as an embryo selection tool in the hope of increasing live birth rates per transfer. ART cycles are monitored in the UK by the Human Fertilisation and Embryology Authority (HFEA) and in the USA by the Society for Assisted Reproductive Technology (SART). Globally, data are monitored via the ESHRE PGT Consortium.

Study design, size, duration: This cross-sectional study used the HFEA and SART databases to analyse PGT cycle data and make comparisons with IVF data to examine the success of and changes in patient treatment pathways. Both data sets were analysed from 2014 to 2016. The UK data included 3385 PGT cycles and the USA data included 94 935 PGT cycles.

Participants/materials, setting, methods: Following an extensive review of both databases, filters were applied to analyse the data. An assessment of limitations of each database was also undertaken, taking into account data collection by the ESHRE PGT Consortium. In the UK and USA, the publicly available information from these datasets cannot be separated into different indications.

Main results and the role of chance: The proportion of PGT cycles as a total of ART procedures has remained the same in the UK but increased annually in the USA from 13% to 27%. Between 2014 and 2016 inclusive, 3385 PGT cycles have been performed in the UK, resulting in 1074 PGT babies being born. In the USA 94 935 PGT cycles have been performed, resulting in 26 822 babies being born. This gave a success rate per egg collection for PGT of 32% for the UK and 28% for the USA. Analysis of the data by maternal age shows very different patient populations between the UK and USA. These differences may be related to the way PGT is funded in the UK and USA and the lack of HFEA support for PGT for aneuploidy.

Limitations, reasons for caution: Data reported by the HFEA and SART have different limitations. As undertaken by the ESHRE PGT Consortium, both data sets should separate PGT data by indication. Although the HFEA collects data from all IVF clinics in the UK, SART data only represent 83% of clinics in the USA.

Wider implications of the findings: Worldwide, a consistent reporting scheme is required in which success rates can convey the effectiveness of PGT approaches for all indications.

Study funding/competing interest(s): No specific funding was obtained and there are no competing interests to declare that are directly related to this project. Joyce Harper is the director of the Embryology and PGD Academy, which offers education in these fields.

Keywords: ART; PGD; PGS; UK; USA; preimplantation genetic testing; reproductive genetics.

Figure 1

Data from the HFEA on the use of PGT for the years 2014–2016. (A) PGT-A live birth rates per year. For fresh PGT-A the live birth rate (LBR) per treatment cycle for the years 2014, 2015 and 2016 was 22.0% (72/327), 15.8% (63/400) and 14.3% (19/133) respectively. For fresh PGT-A the LBR per embryo transferred for the years 2014, 2015, 2016 was 30.6% (72/235), 27.8% (63/227) and 23.5% (9/81), respectively. For frozen PGT-A the LBR per treatment cycle for the years 2014, 2015, 2016 was 26.8% (15/56), 31.6% (61/193) and 36.6% (100/273), respectively. For frozen PGT-A the LBR per embryo transferred for the years 2014, 2015, 2016 was 23.1% (15/65), 30.2% (61/202) and 37.0% (100/270), respectively. (B) PGT-M/SR LBRss per year. For fresh PGT-M/SR the LBR per treatment cycle for the years 2014, 2015 and 2016 was 22.7% (58/256), 30.3% (46/152) and 18.9% (25/132), respectively. For fresh PGT-M/SR the LBR per embryo transferred for the years 2014, 2015 and 2016 was 29.7% (58/195), 37.1% (46/124) and 29.8% (25/84), respectively. For frozen PGT-M/SR the LBR per treatment cycle for the years 2014, 2015 and 2016 was 32.7% (115/352), 38.2% (204/535) and 37.5% (216/576), respectively. For the PGT-M/SR the LBR per embryo transferred was 30.2% (115/381), 34.9% (204/584) and 36.5% (216/592), respectively. HFEA: Human Fertilisation and Embryology Authority, PGT-A: preimplantation genetic testing aneuploidy, PTC: per treatment cycle, PET: per embryo transferred, PGT-M/SR monogenic defects/chromosomal structural rearrangements.

Figure 2

Data from the HFEA on PGT treatment cycles for the years 2014–2016. (A) PGT-A treatment cycles by age, per year. For 18–34 year olds the percentage of women in the age group from 2014, 2015 and 2016 was 16.5% (63/383), 18.0% (107/593) and 18.5% (75/406), respectively. For 35–37 year olds the percentage of women in the age group from 2014, 2015 and 2016 was 17.0% (65/383), 16.0% (95/593) and 20.7% (84/406), respectively. For 38–39 year olds the percentage of women in the age group from 2014, 2015 and 2016 was 14.6% (56/383), 16.5% (98/593) and 18.0% (73/406), respectively. For 40–42 years olds this was 31.9% (122/383), 31.5% (187/593), 28.1% (114/406), respectively. For 43–44 year olds this was 15.9% (61/383), 13.2% (78/593) and 13.1% (53/406), respectively. For the over 44 year olds for the percentage of women in the age group from 2014, 2015 and 2016 this was 4.2% (16/383), 4.7% (28/593) and 1.7% (7/406), respectively. Post-hoc tests were performed to show the 40–42 years age category was significantly higher than all other age categories (P < 0.001). The over 44 years age group made up the lowest percentage of PGT-A cycles (P < 0.05). (B) PGT-M/SR treatment cycles by age, per year. For 18–34 year olds the percentage of women in the age group from 2014, 2015 and 2016 was 60.9% (371/609), 60.7% (417/687) and 59.9% (424/708), respectively. For 35–37 year olds the percentage of women in the age group from 2014, 2015 and 2016 was 23.8% (145/609), 22.7% (156/687) and 25.7% (182/708), respectively. For 38–39 year olds the percentage of women in the age group from 2014, 2015 and 2016 was 9.9% (60/609), 11.5% (79/687) and 10.0% (71/708), respectively. For 40–42 years olds this was 4.8% (29/609), 4.2% (29/687), 3.8% (27/708), respectively. For 43–44 year olds this was 0.2% (1/609), 0.9% (6/687) and 0.6% (4/708), respectively. For the over 44 year olds for the percentage of women in the age group from 2014, 2015 and 2016 this was 0.5% (3/609), 0% (0/687) and 0% (0/708), respectively. Post-hoc tests showed the percentages of women in the 18–34, 35–37 and 38–39 year age groups were significantly higher than all other age groups (P < 0.001).

Figure 3

Data from the HFEA on the use of PGT, by age group, for the years 2014–2016. (A) PGT-A LBRs per year by age. The fresh PET LBR for under 38 s for the years 2014, 2015 and 2016 was 29.9% (32/107), 36.8% (35/95) and 20.0% (5/25), respectively. The fresh PET LBR for 38 and over for the years 2014, 2015 and 2016 was 31.3% (40/128), 21.2% (28/132) and 25.0% (14/56), respectively. The fresh PTC LBR for under 38 s for the years 2014, 2015 and 2016 was 31.1% (32/103), 30.4% (35/115) and 12.5% (5/40), respectively. The fresh PTC LBR over 38 and over for the year 2014, 2015 and 2016 was 17.9% (40/224), 9.8% (28/285) and 15.1% (14/93), respectively. The frozen PET LBR for under 38 s for the years 2014, 2015 and 2016 was 23.3% (7/30), 29.0% (29/100) and 35.9% (47/131). The frozen PET LBR for ages 38 and over for the years 2014, 2015 and 2016 was 22.8% (8/35), 31.4% (32/102), and 38.1% (53/139), respectively. The frozen PTC LBR for ages under 38 for the years 2014, 2015 and 2016 was 28.0% (7/25), 33.3% (29/87) and 39.5% (47/119), respectively, and the frozen PTC LBR for ages 38 and over for the years 2014, 2015 and 2016 was 25.8% (8/31), 30.2% (32/106) and 34.4% (53/154), respectively. Statistical analysis via an ANOVA test showed no evidence for differences between LBR PTC and PET in terms of age groups (P = 0.146 and P = 0.823, respectfully) or frozen cycles (P = 0.555) but there was a significant difference in fresh cycles (P = 0.023). (B) PGT-M/SR LBRs per year by age. The LBR for fresh PET for under 38 s for the years 2014, 2015 and 2016 were 30.1% (49/163), 44.1% (41/93) and 31.4% (21/67), respectively. The LBR for fresh PET for ages 38 and over for the years 2014, 2015 and 2016 were 9.8% (3/32), 16.1% (5/31) and 23.5% (4/17), respectively. The LBR for fresh PTC under 38 for the years 2014, 2015 and 2016 was 23.2% (49/211), 34.5% (41/119) and 20.0% (21/105), respectively. The LBR for fresh PTC ages 38 and over for the years 2014, 2015, and 2016 was 6.5% (3/46), 15.2% (5/33) and 14.8% (4/27), respectively. The LBR for frozen PET for under 38 s for the years 2014, 2015 and 2016 was 32.5% (107/329), 37.2% (182/489) and 27.2% (191/514). The LBR for frozen PET ages 38 and over for the years 2014, 2015 and 2016 was 42.1%, (8/19), 23.2% (22/95), 32.5% (25/77), respectively. The LBR for frozen PTC for ages under 38 for the years 2014, 2015 and 2016 was 35.1% (107/305), 40.1% (182/454), and 38.1% (191/501), respectively. The LBR for frozen PTC for ages 38 and over for the years 2014, 2015 and 2016 was 17.0% (8/47), 27.2% (22/81) and 33.3% (25/75), respectively. ANOVA analysis was carried out and showed the LBR PTC for both fresh and frozen cycles was higher in patients under 38 years than over 38 years (P = 0.002), whereas the LBR PET did not differ by age (P = 0.077). The LBR PTC and PET did not differ for frozen cycles (P = 0.158) but there was a difference between LBR PTC and PET in fresh cycles (P−0.002).

Figure 4

SART data—PGT LBRs per year (fresh and frozen cycles). The LBR per egg collection for the years 2014, 2015 and 2016 was 33.6% (5311/15 826), 30.7% (8102/26 393) and 30.1% (10 158/33 718) and the LBR per embryo transfer procedure for the years 2014, 2015 and 2016 was 52.8% (5311/10 058), 51.1% (8102/15 862) and 54.9% (10 158/18 512), respectively. SART: Society for Assisted Reproductive Technology.

Figure 5

SART data—PGT treatment cycles (fresh and frozen) by age, per year. For under 35 s the percentage of women in the age group from 2014, 2015 and 2016 was 30.1% (4754/15 826), 30.7% (8099/26 393) and 32.6% (10 991/33 718), respectively. For 35–37 year olds the percentage of women in the age group from 2014, 2015 and 2016 was 21.3% (3365/15 826), 22.9% (6041/26 393) and 22.7% (7655/33 718), respectively. For 38–40 year olds the percentage of women in the age group from 2014, 2015 and 2016 was 26.0% (4111/15 826), 25.2% (6643/26 393) and 25.1% (8458/33 718), respectively. For 41–42 year olds the percentage of women in the age group from 2014, 2015 and 2016 was 14.6% (2304/15 826), 13.7% (3604/26 393) and 12.5% (4223/33 718), respectively. For over 42 year olds the percentage of women in the age group from 2014, 2015 and 2016 was 8.2% (1292/15 826), 7.6% (2006/26 393) and 7.1% (2391/33 718), respectively.

Figure 6

SART data—PGT LBRs per year by age group. The LBR per cycle started under age 38 for the years 2014, 2015 and 2016 were 42.3% (3436/8119), 38.2% (5400/14 140) and 38.9% (7253/18 646), respectively. The LBR per cycle started 38 years and over for the years 2014, 2015 and 2015 and 2016 was 24.3% (1874/7707), 22.1% (2702/12 253) and 19.3% (2905/15 072) respectively. The LBR per egg collection under 38 for the years 2014, 2015 and 2016 was 42.3% (3436/8119), 38.2% (5400/14 140) and 38.9% (7253/18 646), respectively. The LBR per egg collection age 38 and over for the years 2014, 2015 and 2016 was 24.3% (1874/7707), 22.1% (2702/12 253) and 19.3% (2905/15 072), respectively. The LBR per embryo transfer procedure for ages under 38 for the years 2014, 2015 and 2016 was 54.0% (3435/6364), 55.4% (5855/10 576) and 56.3% (72 481/12 887), respectively. The LBR per embryo transfer procedure for ages 38 and over for the years 2014, 2015 and 2016 was 50.7% (1874/3694), 51.1% (2702/5286) and 51.0% (2902/5625), respectively.