Comparison of neonatal outcomes following progesterone use during ovarian stimulation with frozen-thawed embryo transfer

Cytoplasmic sperm injection (ICSI) - A systematic review of the literature

Background: Progestin-primed ovarian stimulation (PPOS) stimulates ovaries to block the premature surge of luteinizing hormone (LH) by using micronized progesterone or a progestin during the follicular phase instead of the conventional gonadotropin-releasing hormone (GnRH) analogues or GnRH antagonists downregulating LH to obtain multi-follicle engagement. Current work aims to assess the influence of progestogen treatment on ovarian stimulation and the ability to control LH surge, its efficacy and suitability in retrieving oocytes, without affecting the embryo quality and its benefit among infertile women long-term outcomes on children compared to standard stimulation protocols. Materials and Methods: The literature review used the randomized control trials published in the Pubmed database from January 2015 to April 2021. To generate the citation list, the following keywords were used: 'progestin-primed ovarian stimulation', 'PPOS', 'micronized progesterone', 'medroxyprogesterone', and/or 'dydrogesterone'. The selected articles analyzed the cohort, intervention, and scheme of the progestin-primed ovarian stimulation protocol in controlled ovarian stimulation (COS) for in-vitro fertilization (IVF)/intra cytoplasmic sperm injection (ICSI) used in Assisted Reproductive Technologies (ART). Results: Overall we concluded that PPOS for IVF/ICSI in ART results in a higher number of obtained embryos, lower incidence of OHSS, equal duration of stimulation, number of retrieved oocytes, and number of MII oocytes. It is also suggested that long-term safety in children shows no significant difference between the study and control groups. Conclusions: Despite the outcomes of progestin stimulation cycles among all cohorts, we concluded that poor ovarian responders, patients with PCOS, women of advanced age and oocyte donors benefit the most from using PPOS.

A randomized controlled trial to compare the live birth rate of the first frozen embryo transfer following the progestin-primed ovarian stimulation protocol vs. the antagonist protocol in women with an anticipated high ovarian response

OBJECTIVE

To compare the live birth rate of the first frozen embryo transfer (FET) after ovarian stimulation by the progestin-primed ovarian stimulation (PPOS) protocol vs. the antagonist protocol in women with an anticipated high ovarian response who were undergoing in vitro fertilization.

DESIGN

Randomized controlled trial.

SETTING

A tertiary assisted reproduction center.

PATIENTS

Women with infertility aged <43 years undergoing the first in vitro fertilization cycle and having antral follicle count of >15.

INTERVENTIONS

Medroxyprogesterone 10 mg daily was given from the start of ovarian stimulation until the day of ovulation trigger in the PPOS protocol. In the antagonist protocol, an antagonist 0.25 mg daily was given from the sixth day of ovarian stimulation until the day of ovulation trigger. Blinding was not possible for women or physicians but the biostatistician was blinded to the group assignment.

MAIN OUTCOME MEASURE

Live birth rate of the first FET cycle.

RESULTS

A total of 784 women were recruited from June 2020 and October 2021 and assigned randomly in a 1:1 ratio into two groups: PPOS group (n = 392) and antagonist group (n = 392). Embryo transfer was either cancelled or postponed in 62 women (62/392, 15.8%) in the PPOS group and 65 (65/392, 16.6%) in the antagonist group because of no transferable embryos or no FET within 6 months after randomization. The two groups were similar in demographic characteristics and the numbers of oocytes obtained or fertilized, cleaving embryos, good-quality embryos at day 3, blastocysts developed, and embryos or blastocysts frozen. There was no statistically significant difference in the live birth rate of the first FET cycle between the PPOS and antagonist groups on the basis of both the intention-to-treat analysis (37.5.0% [147/392] vs. 32.7% [128/392]; relative risk, 1.148 [95% confidence interval, 0.949-1.390]) and per-protocol analysis (44.5% [147/330] vs. 39.1% [128/327]; relative risk, 1.138 [95% confidence interval, 0.950-1.364]). Both groups showed comparable clinical pregnancy, ongoing pregnancy, miscarriage, multiple pregnancy, ectopic pregnancy, and cumulative live birth rates.

CONCLUSION

The live birth rates of the first FET following the PPOS and antagonist protocols were comparable in women with an anticipated high ovarian response.

CLINICAL TRIAL REGISTRATION NUMBER

NCT04414761 (ClinicalTrials.gov).

Comparison of the neonatal outcomes of progestin-primed ovarian stimulation and flexible GnRH antagonist protocols: a propensity score-matched cohort study

Objective

To compare the neonatal outcomes of progestin-primed ovarian stimulation (PPOS) and flexible gonadotropin-releasing hormone (GnRH) antagonist protocols.

Methods

This was a retrospective propensity score-matched (PSM) cohort study. Women who underwent their first frozen embryo transfer (FET) cycle with freezing of all embryos followed by PPOS or GnRH antagonist protocols between January 2016 and January 2022 were included. Patients using PPOS were matched with the patients using GnRH antagonist at a 1:1 ratio. The main focus of this study was the neonatal outcomes of singleton live births, including preterm birth (PTB), low birth weight (LBW), small for gestational age (SGA), macrosomia and large for gestational age (LGA).

Results

After 1:1 PSM, a total of 457 PPOS and 457 GnRH antagonist protocols were included for analysis. The average starting dose of gonadotropin (275.1 ± 68.1 vs. 249.3 ± 71.3, P<0.01) and total dose of gonadotropin (2799.6 ± 579.9 vs. 2634.4 ± 729.1, P<0.01) were significantly higher in the PPOS protocol than in the GnRH antagonist protocol. The other baseline and cycle characteristics were comparable between the two protocols. The rates of PTB (P=0.14), LBW (P=0.11), SGA (P=0.31), macrosomia (P=0.11) and LGA (P=0.49) did not differ significantly between the two groups. A total of 4 patients in the PPOS group and 3 patients in the GnRH antagonist group qualified as having congenital malformations.

Conclusion

PPOS resulted in singleton neonatal outcomes similar to those of a GnRH antagonist protocol. The application of the PPOS protocol is a safe option for infertility patients.

Neonatal outcomes and congenital malformations in children born after progestin-primed ovarian stimulation protocol

Purpose

The purpose of this study is to assess the safety of progestin-primed ovarian stimulation (PPOS) protocol regarding the neonatal outcomes and congenital malformations in babies born after in vitro fertilization (IVF) and frozen embryo transfer (FET).

Methods

In this large retrospective cohort study, a total of 16,493 infants born between 1 September 2013 and 31 July 2021 from IVF and FET cycles after treatment with either PPOS (n = 15,245) or gonadotropin-releasing hormone antagonist (GnRH-ant) (n = 1,248) were finally enrolled. The primary outcome measure was the incidence of congenital malformations. The secondary outcome measures were rates of low birth weight (LBW), very low birth weight (VLBW), preterm birth (PTB), very preterm birth (VPTB), and early neonatal death.

Results

Birth characteristics for both singletons and twins regarding the sex of infants, gestational age, birth weight, and birth length were comparable between the PPOS group and the GnRH-ant group. Rates of LBW, VLBW, PTB, VPTB, and early neonatal death were also similar. The reanalysis using propensity score matching (PSM) and multivariable logistic regression indicated that the PPOS protocol could not increase the risk of adverse neonatal outcomes compared with the GnRH-ant protocol. Furthermore, no significant difference was observed in the overall incidence of congenital malformations in live-born babies. After PSM and controlling for all confounders, the results remained insignificant with an adjusted odds ratio of 0.66 [95% confidence interval (CI) 0.32-1.34] and 2.43 [95% CI 0.97-6.06], respectively, for singletons and twins.

Conclusions

Our study suggests that compared with GnRH-ant treatment for IVF, the PPOS protocol could not produce a negative effect on the newborn population in terms of neonatal outcomes and congenital malformations.

Progesterone protocol versus gonadotropin-releasing hormone antagonist protocol in women with polycystic ovarian syndrome undergoing in vitro fertilization treatments with frozen-thawed embryo transfer: a prospective randomized controlled trial

Background

Exogenous progestational agents have recently been introduced as an alternative pituitary modulator for the prevention of premature luteinizing hormone (LH) surges during in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) treatments. There is increasing evidence that frozen-embryo transfer (FET) is associated with a lower risk of ovarian hyperstimulation syndrome (OHSS) in women with polycystic ovary syndrome (PCOS). Herein, we compared the clinical outcomes of the progesterone protocol with the gonadotropin releasing hormone antagonist (GnRH-ant) protocol in PCOS patients with a ‘‘freeze-all’’ strategy.

Methods

In this prospective single-central randomized controlled trial, a total of 120 PCOS patients undergoing their first IVF/ICSI treatment were randomly assigned to receive the progesterone protocol (study group) or GnRH-ant protocol (control group). The main outcome was the number of oocytes retrieved. Secondary outcomes included the incidence of premature LH rise/surge, the number of viable embryos, and pregnancy outcomes.

Results

The number of retrieved oocytes (14.65±7.64 versus 12.8±8.57) and viable embryos (5.38±3.54 versus 5.03±3.92) in the study group were comparable to those in the control group (P>0.05). Similarly, no between-group differences were found in the number of mature oocytes, fertilized oocytes, cleaved embryos, and the viable embryo rate per oocyte retrieved (P>0.05). However, the oocyte retrieval rate (66.02%±19.63% versus 54.38%±26.39%) and fertilization rate (78.12%±18.41% versus 62.76%±23.32%) in the study group were significantly more than that in the control group (P<0.05). The mean serum LH value on day 6–7 was lower in the study group than that in the control group (7.47±0.97 versus 3.98±0.52 IU/L, P<0.05), and the incidence of premature LH rise was higher in the study group than in the control group, although no patients experienced premature LH surge. The clinical pregnancy rate [58.82% vs. 57.32%, RR 0.94 (95% CI: 0.508, 1.738), P>0.05] and implantation rate [43.21% vs. 41.4%, RR 0.929 (95% CI: 0.595, 1.448), P>0.05] were also similar between the two groups.

Conclusions

The progesterone protocol is comparable with the GnRH-ant protocol regarding oocyte/embryo yields and the probability of clinical pregnancy in PCOS patients, but the two regimens were distinct in the regulation of pituitary LH secretion.

Trial registration number

Chictr.org.cn: ChiCTR-IOR-15006633.

Validating the Use of Corifollitropin Alfa in Progestin-Primed Ovarian Stimulation Protocol on Normal and High Responders by Comparing with Conventional Antagonist Protocol: A Retrospective Study

Our previous study showed a satisfactory reproductive outcome resulting from the patient-friendly ovarian stimulation protocol using long-acting follicle stimulation hormone (FSH) plus oral medroxyprogesterone acetate (MPA). The present retrospective study aims to compare the efficacy of the patient-friendly ovarian stimulation protocol with that of the antagonist protocol on normal and high responders aged between 24 and 39 years in a tertiary fertility center in Taiwan. To prevent premature luteinizing hormone (LH) surge, oral MPA was given to patients in group 1 (n = 57), whereas antagonist protocol was applied to group 2 (n = 53). Duration and dosage of stimulation, number of injections and visits before trigger, incidence of premature LH surge, number of oocytes retrieved, fertilization rate, cleavage rate, rate of good embryos available, incidence of ovarian hyperstimulation syndrome, cumulative clinical pregnancy rate and live birth rate per retrieval were compared between groups. We conclude that our patient-friendly ovarian stimulation protocol with MPA demonstrates satisfactory stimulation and reproductive outcomes that are comparable to those of an antagonist protocol.

Impact of progestin ovarian stimulation on newborn outcomes: a meta-analysis

OBJECTIVES

To compare progestin ovarian stimulation protocols with gonadotropin-releasing hormone analogue (agonists and antagonists) protocols on newborn outcomes.

METHODS

The PubMed, Embase, Cochrane Central Register of Controlled Trials, and BioMed Central databases were searched for studies comparing progestin prime ovarian stimulation (PPOS) protocols with gonadotropin-releasing hormone analogues. Data were pooled by meta-analysis using a random effects model.

MAIN OUTCOME MEASURES

Primary endpoint was the risk of newborn congenital malformations.

RESULTS

A total of 4 studies involving 9274 live-born infants were included. No important harm was observed with PPOS in terms of congenital malformations (OR 0.92; 95% CI 0.63-1.34; p = 0.65) (very low quality of evidence (QOE)) and low birth weight (OR 1.06; 95% CI 0.95-1.18; p = 0.29) (very low QOE) as compared with GnRH-a short protocols. In addition, a trend to a lower risk of preterm birth (OR 0.90; 95% CI 0.80-1.02; p = 0.10) (very low QOE) was found among patients treated with a PPOS protocol.

CONCLUSIONS

PPOS protocols, compared with GnRH-a protocols, are associated with a similar congenital malformation risk profile. Therefore, PPOS might represent a safe and appealing treatment option for infertile patients.

Outcomes of fertility preservation in women with endometriosis: comparison of progestin-primed ovarian stimulation versus antagonist protocols

BACKGROUND

PPOS protocols, initially described for FP in women with cancer, have many advantages compared to antagonist protocols. PPOS protocols were not evaluated for women with endometriosis. The objective of the study was to describe fertility preservation outcomes in women with endometriosis and to compare an antagonist protocol with a Progestin-Primed Ovarian Stimulation (PPOS) protocol.

METHOD

We conducted a prospective cohort study associated with a cost-effectiveness analysis in a tertiary-care university hospital. The measured outcomes included the numbers of retrieved and vitrified oocytes, and direct medical costs. In the whole population, unique and multiple linear regressions analysis were performed to search for a correlation between individual characteristics and the number of retrieved oocyte.

RESULTS

We included 108 women with endometriosis who had a single stimulation cycle performed with either an antagonist or a PPOS protocol. Overall, 8.1 ± 6.6 oocytes were retrieved and 6.4 ± 5.6 oocytes vitrified per patient. In the multiple regression model, age (p = 0.001), prior ovarian surgery (p = 0.035), and anti-Mullerian hormone level (p = 0.001) were associated with the number of retrieved oocytes. Fifty-four women were stimulated with an antagonist protocol, and 54 with a PPOS protocol. A mean of 7.9 ± 7.4 oocytes were retrieved in the antagonist group and 8.2 ± 5.6 in the PPOS group (p = 0.78). A mean of 6.4 ± 6.4 oocytes were vitrified in the antagonist group and 6.4 ± 4.7 in the PPOS group (p = 1). In the cost-effectiveness analysis, the PPOS protocol was strongly dominant over the antagonist protocol.

CONCLUSION

Fertility preservation procedures are feasible and effective for patients affected by endometriosis. Antagonist and PPOS protocols were associated with similar results but the medico-economic analysis was in favor of PPOS protocols.

Progestins versus GnRH analogues for pituitary suppression during ovarian stimulation for assisted reproductive technology: a systematic review and meta-analysis

This systematic review and meta-analysis of comparative studies investigated whether progestins are as effective as gonadotrophin releasing hormone (GnRH) analogues for pituitary suppression in assisted reproduction. The primary outcome was live birth rate per woman. Secondary outcomes were live birth or ongoing pregnancy per woman and per embryo transfer, ongoing pregnancy, clinical pregnancy, numbers of oocytes and metaphase-two oocytes, duration of stimulation and gonadotrophin consumption. Adverse events included miscarriage, ectopic pregnancy and multiple pregnancy rates. The GRADE system was used to assess the quality of evidence. Seven studies involving a total of 2047 women were included. Three studies compared a progestin with a GnRH antagonist and four studies compared a progestin with a GnRH agonist. Most studies are non-randomized and report outcomes per embryo transfer, rather than per woman. Although progestins were similar to GnRH antagonists in effectiveness and safety parameters, they were associated with significantly higher live birth or ongoing pregnancy per embryo transfer compared with the short GnRH agonist protocol (RR 1.49, 95% CI 1.16 to 1.91). Progestin primed stimulation lasted significantly longer (mean difference 0.61 days, 95% CI 0.33 to 0.89) and required significantly more gonadotrophins (mean difference 433.2 IU, 95% CI 311.11 to 555.19) than the short GnRH agonist protocol, but the differences were clinically negligible. Safety parameters were similar between progestins and GnRH agonists. In conclusion, progestins can effectively prevent premature ovulation in assisted reproductive technology cycles. If larger and well-designed studies confirm these findings, progestins may be an effective and low-cost alternative to GnRH analogues when a fresh embryo transfer is not planned owing to a medical indication.

Late Follicular Phase Ovarian Stimulation Without Exogenous Pituitary Modulators

Introduction: A gonadotropin-releasing hormone antagonist is the most common modulator used to prevent the premature luteinizing hormone (LH) surge when ovarian stimulation was initiated in the late follicular phase. We aimed in this study to evaluate the feasibility of performing ovarian stimulation in the late follicular phase without the use of exogenous pituitary modulators. Methods: Data were retrospectively collected from 404 normo-ovulatory patients who underwent their first in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) treatment in our department. One hundred sixteen subjects in the study group received ovarian stimulation when a dominant follicular diameter of ≥ 10 mm was confirmed by transvaginal ultrasonography after menstrual cycle day 6, which entailed a daily injection of gonadotropin until the trigger day, while 288 subjects in the control group received ovarian stimulation in the early follicular phase under a progesterone protocol. The primary outcome was the number of mature oocytes. Results: There was no statistical difference in the number of mature oocytes between the two groups (9.67 ± 5.33 in the study group vs. 9.38 ± 5.15 in the control group, P = 0.693). No secondary LH surges in the study group and no premature LH surges in the control group were found during ovarian stimulation. The good-quality embryo rate per oocyte retrieved showed no significant difference between the two groups (35.22 vs. 35.91%, P = 0.665). The clinical pregnancy rate per transfer was 54.55% in the study group and 56.48% in the control group (P = 0.718), and the implantation rate was similar between the two groups (36.94 vs. 37.77%, P = 0.829). Conclusions: Our study revealed that late follicular phase ovarian stimulation could be performed without an exogenous pituitary modulator.

Effects of intramuscular and vaginal progesterone supplementation on frozen-thawed embryo transfer

This study was to investigate effects of progesterone vaginal sustained-release gel and intramuscular injection of progesterone on frozen-thawed embryos transfer in 3013 patients receiving vaginal progesterone sustained-release gel and progesterone injection in artificial cycle for frozen-thawed embryo transfer. All patients were divided into two groups: group A with progesterone intramuscular injection (60 mg/d) plus dydrogesterone (10 mg tid) and group B with progesterone vaginal sustained-release gel of progesterone (90 mg/d) plus dydrogesterone (10 mg tid). There were 1988 women in group A treated with progesterone injection and 1025 women in group B with progesterone vaginal sustained-release gel. There were no statistically (P > 0.05) significant difference between the two groups in age, years of infertility, body mass index, endometrial thickness at transfer time, the average numbers of embryo transferred, cause of infertility, number of cycles, pregnancy rate and ectopic pregnancy rate. No significant (P > 0.05) differences existed in the clinical pregnancy (52.5% vs. 56.0%) and ectopic pregnancy (2.2% vs. 3.0%) rate between groups A and B. However, group B with vaginal progesterone supplementation had significantly (P < 0.05) greater implantation (37.0% vs 34.4%), delivery (45.1% vs. 41.0%) and live birth (45.0% vs. 40.8%) rate than group A with intramuscular progesterone injection, whereas group A had significantly (P < 0.05) greater early abortion rate (19.4% vs. 15.3%) than group B. This study showed that vaginal gel progesterone supplementation has good effects on frozen-thawed embryo transfer and can significantly increase the rate of implantation, delivery and live birth but decrease the abortion rate compared with intramuscular progesterone injection.

Randomized, Controlled Pilot Study of Low-Dose Human Chorionic Gonadotropin Administration Beginning From the Early Follicular Phase for Women With Polycystic Ovarian Syndrome Undergoing Ovarian Stimulation Using the Progesterone Protocol

Purpose: To illustrate whether low-dose human chorionic gonadotropin (hCG) administration during the early follicular phase could reduce the number of large preovulatory follicles in women with polycystic ovarian syndrome (PCOS) undergoing ovarian stimulation using the progesterone protocol. Methods: We performed a randomized, controlled pilot trial at a university-affiliated tertiary hospital. A total of 40 infertile women undergoing their first in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) treatment with the freeze-all strategy were included. Human menopausal gonadotropin (hMG) and progesterone soft capsule 100 mg/d were added simultaneously beginning from menstrual cycle day 3 for all participants. Low-dose hCG (200 IU) was injected every 3 days in the study group from the first day of ovarian stimulation until trigger. The primary outcome was the number of large preovulatory follicles. Secondary outcomes included the incidence of ovarian hyperstimulation syndrome (OHSS); the number of oocytes retrieved, mature oocytes, and good-quality embryos; and clinical results after frozen-thawed embryo transfer (FET) cycles. Results: The study group had slightly more large preovulatory follicles than the control group (17.75 ± 10 vs. 13.2 ± 5.34; P > 0.05). None of the participants experienced severe OHSS. There were no statistically significant differences in the number of oocytes retrieved (15.9 ± 8.46 vs. 15.75 ± 6.96), mature oocytes (13.55 ± 6.56 vs. 13.4 ± 6.34), and good-quality embryos (5.5 ± 3.41 vs. 4.9 ± 2.99) between the two groups (P > 0.05). Clinical pregnancy rates (65.52 vs. 41.94%; P = 0.067) and live birth rates (48.28 vs. 35.48%; P = 0.315) per transfer following FET of the study group were higher than those of the control group, but without statistical significance. Conclusions: Administration of low-dose hCG from the early follicular phase for PCOS patients undergoing ovarian stimulation with progesterone protocol may lead to slightly more early preovulatory follicles and marginally, but not significantly, higher clinical pregnancy rates. A continuous trial should be performed to explore the effects of supplementation with different doses of hCG from the start of ovarian stimulation in PCOS patients using the progesterone protocol. Clinical Trial Registration: Chictr.org.cn, identifier: ChiCTR-IOR-15007165.

Evaluation of Ovarian Stimulation Initiated From the Late Follicular Phase Using Human Menopausal Gonadotropin Alone in Normal-Ovulatory Women for Treatment of Infertility: A Retrospective Cohort Study

Objective: To investigate the feasibility of ovarian stimulation initiated in the late follicular phase using human menopausal gonadotropin (hMG) alone in ovulatory patients undergoing in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) treatments by comparison with that of the short gonadotropin-releasing hormone agonist (GnRH-a) protocol in terms of ovarian response, embryological characteristics, and pregnancy outcomes following frozen-thawed embryo transfer (FET) cycles. Design: Retrospective cohort study. Setting: A university-affiliated tertiary hospital. Patients: 135 infertile women undergoing their first IVF/ICSI treatment with the freeze-all strategy. Interventions: In the study group, ovarian stimulation was initiated in the late follicular phase using hMG alone, with the confirmation of dominant follicular diameter ≥ 14 mm, while a short GnRH-a protocol was adopted in the control group. Oocyte maturation was induced by human chorionic gonadotropin in both groups. All good quality embryos were cryopreserved for later transfer. Main Outcome Measures: The primary outcome was the incidence of premature luteinizing hormone (LH) surge. Secondary outcomes were the number of mature oocytes retrieved, good-quality embryo rate per oocyte retrieved, and clinical pregnancy rate following FET cycles. Results: No premature LH surge was detected during ovarian stimulation in the study group. There was no statistically significant difference in the number of mature oocytes between the two groups (10 ± 5.6 in the study group vs. 8.51 ± 5.03 in the control group, P = 0.11). Good-quality embryo rate per oocyte retrieved did not differ between the two groups: 40.18% (313/779) vs. 36.67% (253/690), P = 0.167. Clinical pregnancy rate per transfer following FET was comparable between the two groups (61.33 vs. 52.5%, P = 0.267). Conclusions: Our study shows that ovarian stimulation initiated in the late follicular phase using hMG alone may be a feasible alternative for normal-ovulatory women undergoing IVF/ICSI treatment with the freeze-all strategy.

Comparison of neonatal outcomes and live-birth defects after progestin-primed ovarian stimulation versus conventional ovarian stimulation for in vitro fertilization: A large retrospective cohort study

Progestin-primed ovarian stimulation (PPOS) is a new ovarian stimulation regimen for in vitro fertilization (IVF), with the advantages of an oral administration route and more control over preovulatory luteinizing hormone (LH) levels. Assessing the safety of this novel regimen is an important premise for its routine practice.We conducted a large retrospective cohort study for infants born between August 2014 and April 2017 from IVF and embryo transfer cycles after either PPOS and the conventional gonadotropin-releasing hormone-agonist (GnRH-a) short protocol at our center. Around 1589 live-born infants were finally enrolled, corresponding to 1258 frozen-thawed (FET) cycles, which led to 855 live-born infants from PPOS (659 FET cycles) and 734 live-born infants from the short protocol (599 FET cycles).Birth characteristics regarding gestational age, birth weight and length, infant sex, and early neonatal death were comparable between the 2 groups. The incidence of live-birth defects in the PPOS group (1.52%) was similar to that in the short protocol group (1.63%) and was not statistically significant. For birth defects, the risk significantly increased for multiple births, and the adjusted odds ratio was 3.14 (95% confidence interval [CI]: 1.25-7.88). No associations were found between congenital birth defects and maternal age, body mass index (BMI), the duration of infertility, method of insemination, infant sex, embryo stage at transfer, the number of embryos transferred or ovarian stimulation regimen.Our study shows that the neonatal outcomes and risk of congenital malformations were similar between the PPOS and conventional GnRH-a short protocol. However, multiple pregnancy led to a higher likelihood of birth defects.