Abstract
This study used national surveillance data from the Society for Assisted Reproductive Technology to describe trends and outcomes in assisted reproductive technology cycles using a gestational carrier vs those not using a gestational carrier.
A gestational carrier is someone who carries a pregnancy on behalf of the intended parents after implantation of an embryo created using gametes originating from the intended parents or a third party.1 Use of gestational carriers has increased, likely due to increased visibility; wider availability of assisted reproductive technology services for lesbian, gay, bisexual, transgender, and queer patients2; and evolving laws regarding surrogacy.3
Assisted reproductive technology cycles using a gestational carrier involve unique ethical considerations because the person carrying the pregnancy will not be the parent and is not genetically related to the embryo. Assisted reproductive technology pregnancies are, at baseline, considered higher medical risk.4 However, it is unclear whether the use of nonautologous gametes inherent in gestational carrier pregnancies also confers risk. We used national surveillance data to describe trends and outcomes in assisted reproductive technology cycles using a gestational carrier.
Methods
Deidentified data from the Society for Assisted Reproductive Technology Clinic Outcomes Reporting System involving an embryo transfer between 2014 and 2020 were analyzed. This national surveillance system encompassed 90% of US assisted reproductive technology cycles. This study was exempted by the Emory University institutional review board.
Poisson and linear regression models were used to evaluate the annual number and percentage of assisted reproductive technology cycles using a gestational carrier between 2014 and 2020. Using log binomial regression, we calculated the adjusted relative risk (RR) for pregnancy, clinical pregnancy, and live birth comparing assisted reproductive technology cycles that used vs did not use a gestational carrier, adjusting for age of oocyte donor or intended parent at time of retrieval, infertility diagnosis, donor oocyte use, intracytoplasmic sperm injection, assisted hatching, fresh vs frozen cycle, preimplantation genetic testing, embryo transfer day, and number of embryos transferred.
Among live births, adjusted RRs for gestational age at birth and multiple gestation were calculated to compare cycles that used vs did not use a gestational carrier. The results were considered significant if the 2-tailed 95% CI did not cross 1. SAS version 9.4 (SAS Institute Inc) was used for the analyses.
Results
Between 2014 and 2020, 1 008 205 assisted reproductive technology cycles with an embryo transfer occurred; 40 177 (4.0%) of which used a gestational carrier. The absolute number of assisted reproductive technology cycles involving a gestational carrier increased from 2014 (3538 of 128 936 [2.7%]) to 2019 (8145 of 156 864 [5.2%]) and decreased in 2020 (6909 of 151 060 [4.6%]) (P < .001 for overall trend). Assisted reproductive technology cycles that used a gestational carrier were more likely to have older and nulligravid intended parents, use donor oocytes, have a younger age for oocyte donor or intended parent at time of retrieval, and use preimplantation genetic testing vs cycles that did not use a carrier (Table 1). Two or more embryos were transferred in 27.6% of cycles with a gestational carrier vs 36.0% of cycles without a gestational carrier.
Table 1. Patient Characteristics of Assisted Reproductive Technology (ART) Cycles With an Embryo Transfer to a Gestational Carrier vs Those Without a Gestational Carrier, 2014-2020.
| ART cycles with an embryo transfer, No. (%)a | ||
|---|---|---|
| With a gestational carrier | Without a gestational carrier | |
| No. of cycles | 40 177 (4.0) | 968 028 (96.0) |
| Age group for intended parent at transfer, y | ||
| <35 | 10 149 (25.3) | 405 670 (41.9) |
| 35-37 | 7645 (19.0) | 219 194 (22.6) |
| 38-40 | 7027 (17.5) | 172 579 (17.8) |
| 41-42 | 3839 (9.6) | 77 398 (8.0) |
| >42 | 11 517 (28.7) | 93 187 (9.6) |
| Oocyte source | ||
| Autologous | 19 630 (48.9) | 859 104 (88.7) |
| Donor | 20 547 (51.1) | 108 924 (11.3) |
| Age group for oocyte donor or intended parent at time of retrieval | ||
| <30 | 16 396 (40.8) | 190 793 (19.7) |
| 30-34 | 8410 (20.9) | 337 085 (34.8) |
| 35-37 | 5188 (12.9) | 196 703 (20.3) |
| 38-40 | 3638 (9.1) | 136 474 (14.1) |
| ≥41 | 1929 (4.8) | 73 793 (7.6) |
| Missing | 4616 (11.5) | 33 180 (3.4) |
| Clinic locationb | ||
| Midwest | 4326 (10.8) | 180 324 (18.6) |
| Northeast | 6440 (16.0) | 308 351 (31.9) |
| South | 8148 (20.3) | 306 379 (31.7) |
| West | 21 263 (52.9) | 196 924 (20.3) |
| Race and ethnicity of intended parentc | ||
| Asian | 8165 (20.3) | 94 550 (9.8) |
| Hispanic | 1649 (4.1) | 50 464 (5.2) |
| Non-Hispanic Black | 972 (2.4) | 47 843 (4.9) |
| Non-Hispanic White | 14 149 (35.2) | 439 794 (45.4) |
| Otherd | 344 (0.9) | 7907 (0.8) |
| Missing or unknown | 14 898 (37.1) | 327 470 (33.8) |
| Infertility diagnosise | ||
| Male factorf | 3723 (9.3) | 320 354 (33.1) |
| Tubal factorg | 1348 (3.4) | 123 993 (12.8) |
| Endometriosis | 1270 (3.2) | 76 169 (7.9) |
| Uterine factorh | 15 429 (38.4) | 54 755 (5.7) |
| Recurrent pregnancy loss | 1106 (2.8) | 29 181 (3.0) |
| Ovulatory dysfunction | 10 546 (26.3) | 343 117 (35.4) |
| Diminished ovarian reserve | 10 670 (26.6) | 265 271 (27.4) |
| Unexplained | 1849 (4.6) | 129 429 (13.4) |
| Male-male couple or single malei | 8724 (27.1) | 0 |
| Otherj | 18 911 (47.1) | 180 024 (18.6) |
| Age group for gestational carrier, y | ||
| <30 | 13 472 (33.5) | |
| 30-34 | 14 063 (35.0) | |
| 35-39 | 9739 (24.2) | |
| ≥40 | 2903 (7.2) | |
| No. of prior cyclesk,l | ||
| 0 | 5022 (16.0) | 211 698 (21.9) |
| 1 | 9575 (30.4) | 318 327 (32.9) |
| ≥2 | 16 856 (53.6) | 438 003 (45.2) |
| Prior live birthsk | ||
| 0 | 21 880 (69.6) | 620 838 (64.1) |
| 1 | 5991 (19.1) | 261 377 (27.0) |
| ≥2 | 3314 (10.5) | 83 015 (8.6) |
| Missing | 268 (0.9) | 2798 (0.3) |
| Cycle type | ||
| Fresh | 3912 (9.7) | 328 761 (34.0) |
| Frozen and then thawed | 36 211 (90.1) | 637 691 (65.9) |
| Combination | 54 (0.1) | 1576 (0.2) |
| System or test used | ||
| Assisted hatching on all transferred embryos | 27 608 (68.7) | 590 551 (61.0) |
| Intracytoplasmic sperm injection | 24 512 (61.0) | 601 858 (62.2) |
| Preimplantation genetic testing | 25 407 (63.2) | 297 301 (30.7) |
| Day of embryo transfer | ||
| 2 or 3 | 1720 (4.3) | 122 004 (12.6) |
| 5 or 6 | 37 290 (92.8) | 807 606 (83.4) |
| Other | 1167 (2.9) | 38 418 (4.0) |
| No. of embryos transferred | ||
| 1 | 29 096 (72.4) | 619 947 (64.0) |
| 2 | 10 507 (26.2) | 301 181 (31.1) |
| ≥3 | 574 (1.4) | 46 900 (4.9) |
Includes all ART cycles that resulted in at least 1 embryo transfer.
US Census Bureau regions. Of the 1 008 205 ART cycles, the clinic location was missing for 17 494 (1.7%).
Data were collected by the Society for Assisted Reproductive Technology for all ART cycles.
Includes Alaska Native, American Indian, Native Hawaiian, and Pacific Islander as well as those who identified as having 2 or more races.
Categories are not mutually exclusive.
Due to abnormal semen parameters (eg, oligospermia), azoospermia, and prior vasectomy.
Includes history of tubal ligation, hydrosalpinx, and other tubal disease.
Includes absence of a uterus, significant uterine anomaly, septum, myoma, diethylstilbestrol exposure, and intrauterine adhesions.
Only available for data from 2016 to 2020. The denominator is 32 182.
The majority were for medical conditions that may be a contraindication to pregnancy (eg, maternal heart condition, inflammatory bowel disease).
Data only available for cycles involving a female-intended parent. For data in the “with a gestational carrier” column, the denominator is 31 453.
Includes the number of prior fresh and frozen cycles.
Embryo transfers to a gestational carrier were more likely to result in a pregnancy (73.0% vs 63.4% in those not using a gestational carrier; adjusted RR, 1.06 [95% CI, 1.06-1.07]), clinical pregnancy (63.7% vs 52.9%; adjusted RR, 1.09 [95% CI, 1.08-1.10]), and live birth (54.3% vs 43.6%; adjusted RR, 1.11 [95% CI, 1.10-1.12]) (Table 2) in agreement with prior findings.5 Among cycles with a gestational carrier vs those without a gestational carrier, there was a lower risk of preterm birth (23.2% vs 23.7%, respectively; adjusted RR, 0.80 [95% CI, 0.78-0.82]) and very preterm birth (3.6% vs 3.6%; adjusted RR, 0.76 [95% CI, 0.70-0.83]) after adjusting for pregnancy plurality. Of live births, 14.8% of cycles with a gestational carrier resulted in the birth of twins or higher order multiples vs 12.6% of cycles without a gestational carrier (adjusted RR, 1.15 [95% CI, 1.11-1.18]). In cycles resulting in multiple births, 90.0% with a gestational carrier vs 91.5% without a gestational carrier involved the transfer of 2 or more embryos.
Table 2. Outcomes for Assisted Reproductive Technology (ART) Cycles With a Gestational Carrier vs Those Without a Gestational Carrier, 2014-2020.
| ART cycles with an embryo transfer, No. (%) | RR (95% CI) | Adjusted RR (95% CI)a | ||
|---|---|---|---|---|
| With a gestational carrier | Without a gestational carrier | |||
| Transfer outcome | ||||
| Pregnantb | 29 318 (73.0) | 613 779 (63.4) | 1.15 (1.14-1.16) | 1.06 (1.06-1.07) |
| Clinical pregnancyc | 25 417 (63.7) | 510 251 (52.9) | 1.20 (1.19-1.21) | 1.09 (1.08-1.10) |
| Live birth | 21 649 (54.3) | 420 256 (43.6) | 1.25 (1.23-1.26) | 1.11 (1.10-1.12) |
| Miscarriage | 3638 (14.3) | 87 193 (17.1) | 0.84 (0.81-0.86) | 0.89 (0.86-0.92) |
| Gestational age among live birthsc,d | ||||
| Term | 15 798 (73.2) | 305 093 (72.7) | 1.01 (1.00-1.02) | 1.21 (1.19-1.23)e |
| Pretermf | 5014 (23.2) | 99 305 (23.7) | 0.98 (0.96-1.01) | 0.80 (0.78-0.82)e |
| Very pretermg | 771 (3.6) | 15 216 (3.6) | 0.99 (0.92-1.06) | 0.76 (0.70-0.83)e |
| No. born among live birthsc | ||||
| Singleton | 18 388 (85.2) | 366 662 (87.4) | 1 [Reference] | 1 [Reference] |
| Multiples | 3197 (14.8) | 52 957 (12.6) | 1.17 (1.14-1.21) | 1.15 (1.11-1.18) |
Abbreviation: RR, relative risk.
Adjusted for oocyte age, infertility diagnosis (uterine factor, male factor, unexplained infertility, other female infertility), use of donor oocyte, use of intracytoplasmic sperm injection, use of assisted hatching, fresh vs frozen cycle, use of preimplantation genetic testing, day of embryo transfer, and number of embryos transferred.
As defined by at least a positive biochemical pregnancy test.
Defined as a clinically identifiable intrauterine pregnancy.
Among 441 229 live births. Missing pregnancy plurality for 25 people.
Also adjusted for pregnancy plurality.
Defined as 32 weeks to less than 37 weeks.
Defined as less than 32 weeks.
Discussion
There was an increased likelihood of live birth among assisted reproductive technology cycles with a gestational carrier vs those without a gestational carrier. Gestational carrier use was a risk factor for twins, even after adjusting for the number of embryos transferred. More than one-quarter of embryo transfers to gestational carriers involved 2 or more embryos despite national recommendations of single embryo transfer.1 Given the widespread absence of insurance coverage, each cycle with a gestational carrier imposes steep expenses on intended parents.6 The increased use of preimplantation genetic testing and the high proportion of multiple embryo transfers may have been used to maximize the chance of success per attempt.
Study limitations include inability to investigate pregnancy complications, inability to assess clustering by gestational carrier, and data entry errors. Although the outcomes appear reassuring, multiple gestation risk is high among cycles with a gestational carrier. Further characterization of cycles in which multiple embryos were transferred could elucidate the degree of adherence to recommendations from the American Society for Reproductive Medicine1 or lack thereof.
Section Editors: Jody W. Zylke, MD, Deputy Editor; Karen Lasser, MD, and Kristin Walter, MD, Senior Editors.
Data sharing statement
References
- 1.Practice Committee of the American Society for Reproductive Medicine and Practice Committee of the Society for Assisted Reproductive Technology . Recommendations for practices using gestational carriers: a committee opinion. Fertil Steril. 2022;118(1):65-74. doi: 10.1016/j.fertnstert.2022.05.001 [DOI] [PubMed] [Google Scholar]
- 2.Ethics Committee of the American Society for Reproductive Medicine . Access to fertility treatment irrespective of marital status, sexual orientation, or gender identity: an ethics committee opinion. Fertil Steril. 2021;116(2):326-330. doi: 10.1016/j.fertnstert.2021.03.034 [DOI] [PubMed] [Google Scholar]
- 3.Tsai S, Shaia K, Woodward JT, Sun MY, Muasher SJ. Surrogacy laws in the United States: what obstetrician-gynecologists need to know. Obstet Gynecol. 2020;135(3):717-722. doi: 10.1097/AOG.0000000000003698 [DOI] [PubMed] [Google Scholar]
- 4.Society for Maternal-Fetal Medicine . Society for Maternal-Fetal Medicine consult series #60: management of pregnancies resulting from in vitro fertilization. Am J Obstet Gynecol. 2022;226(3):B2-B12. doi: 10.1016/j.ajog.2021.11.001 [DOI] [PubMed] [Google Scholar]
- 5.Murugappan G, Farland LV, Missmer SA, Correia KF, Anchan RM, Ginsburg ES. Gestational carrier in assisted reproductive technology. Fertil Steril. 2018;109(3):420-428. doi: 10.1016/j.fertnstert.2017.11.011 [DOI] [PubMed] [Google Scholar]
- 6.Lindheim SR, Madeira JL, Ludwin A, et al. Societal pressures and procreative preferences for gay fathers successfully pursuing parenthood through IVF and gestational carriers. Reprod Biomed Soc Online. 2019;9:1-10. doi: 10.1016/j.rbms.2019.09.001 [DOI] [PMC free article] [PubMed] [Google Scholar]
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