Effect of Maternal Age on Pregnancy or Neonatal Outcomes Among 4,958 Infertile Women Using a Freeze-All Strategy

Influence of maternal age on the birthweight of infants delivered from frozen-thawed blastocyst transfer cycles

The aim of this study was to investigate whether maternal age had an effect on the birthweight of singletons delivered from frozen-thawed blastocyst transfer (FBT) cycles. A total of 1203 FBT cycles occurring between July 2011 and June 2021 at a single centre were retrospectively analysed. Based on the maternal age at FBT, the patients were divided into four groups: <30, 30-34, 35-37, and ≥38 years of age. Main outcomes measured included singleton birthweights, preterm births, large-for-gestational-age (LGA) and small-for-gestational-age (SGA) live births among the groups. There was no significant difference in birth weight among the four groups, while the highest birth weight was found in the <30 years group. The incidence of very preterm births and very low birth weights demonstrated an increasing trend with age; on the contrary, the incidence of preterm births, low birth weight (LBW), high birth weight and LGA and SGA live births gradually decreased with increasing age, but these differences were not statistically significant among groups (P>0.05, respectively). Although the proportion of females was lower than that of males, the difference was not statistically significant among the groups. After adjusting for possible confounders, maternal age was found to have no effect on adverse neonatal outcomes in the regression analyses (P>0.05). Birthweight in singleton births from FBT was not affected by maternal age.

Cumulative live birth rate after oocyte in vitro maturation with a pre-maturation step in women with polycystic ovary syndrome or high antral follicle count

PURPOSE

This study evaluated the 24-month cumulative live birth rate (CLBR) for women with polycystic ovary syndrome (PCOS) or high antral follicle count (AFC) who underwent oocyte in vitro maturation (IVM) with pre-maturation step (CAPA-IVM).

METHODS

This multicenter, retrospective study was performed at IVFMD, My Duc Hospital, and IVFMD Phu Nhuan, My Duc Phu Nhuan Hospital from 1 January 2017 to 31 December 2019. All women with PCOS or high AFC treated with a CAPA-IVM cycle were included. Cumulative live birth was defined as at least one live birth resulting from the initiated CAPA-IVM cycle. Where a woman did not return for embryo transfer, outcomes were followed up until 24 months from the day of oocyte aspiration. Logistic regression was performed to identify factors predicting the CLBR.

RESULTS

Data from 374 women were analyzed, 368 of whom had embryos for transfer (98.4%), and six had no embryos for transfer (1.6%). The oocyte maturation rate was 63.2%. The median number of frozen embryos was 4 [quartile 1, 2; quartile 3, 6]. Cumulative clinical pregnancy and ongoing pregnancy rates were 60.4% and 43.6%, respectively. At 24 months after starting CAPA-IVM treatment, the CLBR was 38.5%. Multivariate analysis showed that patient age and number of frozen embryos were significant predictors of cumulative live birth after CAPA-IVM.

CONCLUSIONS

CAPA-IVM could be considered as an alternative to in vitro fertilization for the management of infertility in women with PCOS or a high AFC who require assisted reproductive technology.

Risk Factors of Preterm Birth and Low Birth Weight in Singletons Conceived Through Frozen Embryo Transfer: A Retrospective Study

Background

The risks of adverse perinatal outcomes in offspring conceived following frozen-thawed embryo transfer (FET) assisted reproductive technology (ART) are inconsistent. The aim of this study was to analyze the risk factors for preterm birth and low birth weight in singletons after FET.

Methods

386 FET cycles was conducted at the Reproductive Medicine Center of Meizhou People's Hospital. The relationship between clinical characteristics and outcomes (term birth and preterm birth, normal birth weight and low birth weight) was analyzed.

Results

The rate of primary infertility, basal FSH and T levels, gestational age, birth weight, and proportion of male fetuses were significantly different in the preterm and full-term groups. Logistic regression analysis showed that high maternal age (≥35 years) (OR 3.652, 95% CI: 1.683-7.925, P=0.001), primary infertility (OR 2.869, 95% CI: 1.461-5.632, P=0.002), low FSH level (<6.215 mIU/mL) (OR 3.272, 95% CI: 1.743-6.144, P<0.001), and hormone replacement therapy (HRT) method (OR 2.780, 95% CI: 1.088-7.100, P=0.033) may increase risk of preterm birth after FET. Gestational age and birth weight were significantly different in fetuses with low birth weight (<2500g, n=38) and normal birth weight (≥2500g and <4000g, n=333). Logistic regression analysis showed that low basal FSH level (<6.215 mIU/mL) (OR 0.425, 95% CI: 0.209-0.865, P=0.018), and HRT method of endometrial preparation for FET (OR 0.272, 95% CI: 0.079-0.934, P=0.039) may reduce the risk of low birth weight after FET.

Conclusion

High maternal age, primary infertility, low FSH level, HRT method of endometrial preparation for FET, and male fetus may increase risk of preterm birth after FET. In addition, primary infertility, low basal FSH level, and HRT method of endometrial preparation may reduce the risk of low birth weight after FET.

Impact of Maternal Age on Singleton Birthweight in Frozen Embryo Transfer Cycles

Background

Previous studies have investigated the effect of maternal age on assisted reproductive technology success rates. However, little is known about the relationship between maternal age and neonatal birthweight in frozen embryo transfer (FET) cycles. Whether maternal age influences singleton birthweight in FET cycles remains to be elucidated.

Methods

This study was conducted at a tertiary care center, involving singleton live births born to women undergoing frozen-thawed embryo transfer during the period from January 2010 to December 2017. A total of 12,565 women who fulfilled the inclusion criteria were enrolled and grouped into four groups according to the maternal age: <30, 30-34, 35-39, and ≥40 years old. A multivariable linear regression analysis was conducted to reveal the relationship between maternal age and neonatal birthweight with controlling for a number of potential confounders.

Results

The highest proportions of low birthweight (LBW, 4.1%), high birthweight (1.2%), preterm birth (PTB, 5.9%), and very PTB (0.9%) were found in the group over 40 years old, but no significant difference was observed among the four groups. Additionally, the 35-39-year-old group had the highest rate of very LBW (0.6%), whereas the 30-34-year-old group had the lowest rate of small for gestational age (SGA, 2.7%). However, multivariate analyses revealed that neonatal outcomes including PTB, LBW, and SGA were similar between the different maternal age groups.

Conclusion

Grouping with different maternal age was not associated with mean birthweight and Z-scores of singletons resulting from FET.

Association between paternal age and singleton birthweight in frozen embryo transfer cycles

BACKGROUND

Many studies have considered maternal age as a determinant factor for success in assisted reproductive technologies (ART), but the potential role of paternal age on neonatal outcomes has been overlooked. This study aimed to explore the association between paternal age and birthweight in frozen embryo transfer (FET) cycles.

METHODS

This retrospective study involved singleton live births born to women undergoing frozen embryo transfer from January 2013 to December 2017 at a tertiary care center in Shanghai, China. The paternal age was classified into four categories: ≤ 30, 31-35, 36-40, and ≥ 41 years. The group consisting of respondents with paternal age of 31-35 was set as the reference group. Singleton birthweight was the primary outcome measure. Z-scores were calculated according to gestational age and newborn gender on birthweight based on the national birthweight reference. Multivariable linear regression analysis was performed to reveal the relationship between paternal age and newborns' birthweight after considering several potential confounders.

RESULTS

Exactly 9765 women who fulfilled the inclusion criteria were enrolled. No significant difference was found on mean birthweight (P = 0.082) and gestation-adjusted Z-scores (P = 0.569) among paternal age categories. The reference group and the group with aged 36-40 years had the highest mean birthweight and Z-scores, respectively (3350.2 ± 467.8 g, 0.36 ± 1.00). A decline in mean birthweight with paternal age was observed, and the group over 40 years had the lowest value of 3309.4 ± 474.3 g, but the difference was not statistically significant. In multivariate analyses, the adjusted odds of very low birthweight (LBW), LBW, and high birthweight in the reference group did not significantly differ with the three other groups. After correcting several potential confounders, no significant correlation was observed between paternal age and neonatal birthweight (P = 0.289).

CONCLUSION

Paternal age was not associated with mean birthweight and gestational age- and gender-adjusted birthweight (Z-scores) of singletons among women who became pregnant in FET cycles.

The Impact of Embryo Storage Time on Pregnancy and Perinatal Outcomes and the Time Limit of Vitrification: A Retrospective Cohort Study

BACKGROUND

The technique of embryo cryopreservation has been increasingly applied in clinical settings. However, there has been a concern about the safety and efficacy of long-term freezing of embryos. Therefore, the aim of this study was to evaluate whether storage time of vitrification had any effects on pregnancy as well as perinatal outcomes, further, to explore the appropriate time limit of vitrification.

METHODS

The study included women who underwent at least one frozen-thawed cycle with single embryo transfer between January 1^st, 2016 and September 30^th, 2019. Patients were assigned into 3 groups according to the storage time (<3 months, 3-12 months and >12 months) to evaluate the impact of embryo storage time on pregnancy and perinatal outcomes. To further investigate the time limit of vitrification, propensity score matching was used to compare the primary outcomes of patients with storage time of 1-3 years, 3-5 years, and >5 years to those stored for ≤1 year.

RESULTS

A total of 9806 frozen-thawed embryo transfer cycles were included in our study. After adjustment for confounding variables, no significant differences were found in pregnancy outcomes among groups. However, postponement of transfer increased the risks of large for gestational age and placenta previa. In addition, after propensity score matching, 171 cycles with storage time >5 years were matched with those ≤1 year, both the clinical pregnancy rate and live birth rate decreased significantly when the storage time exceeded 5 years.

CONCLUSIONS

The duration of vitrification did not significantly affect the pregnancy outcomes within 5 years period. However, the clinical pregnancy rate and live birth rate both decreased significantly when the duration of vitrification exceeded 5 years. It is worth noting that the conclusion was drawn from a small sample study after propensity score matching and should be treated with caution. In addition, the cycles were from different time periods, which could have an impact on the results.

Prolonged Cryopreservation Negatively Affects Embryo Transfer Outcomes Following the Elective Freeze-All Strategy: A Multicenter Retrospective Study

BACKGROUND

With the development of embryo freezing and warming technology, frozen-thawed embryo transfer (FET) has been widely utilized. However, studies investigating the association between cryopreservation duration and FET outcomes are limited and controversial, and previous studies did not conduct stratification analyses based on demographic or clinical characteristics.

METHODS

This multicenter retrospective study included 17,826 women who underwent their first FET following the freeze-all strategy during the period from January 2014 to December 2018. Duration of cryopreservation was categorized into five groups: 3-8 weeks, 8-12 weeks, 12-26 weeks, 26-52 weeks, and >52 weeks. Modified Poisson regression and multivariate logistic regression were used to assess the association between cryostorage time of vitrified embryos and transfer outcomes. Moreover, further stratification analyses were performed according to variables with p <0.05 in multivariate models.

RESULTS

In this large multicenter study, we observed that storage duration was inversely associated with the possibility of pregnancy and live birth (p <0.001), but not with the risk of ectopic pregnancy and miscarriage. Stratification analyses based on maternal age, the number of oocytes retrieved, and condition of embryo transferred indicated that the inverse correlation was significant in the subpopulation with characteristics: (1) less than 40 years old, (2) more than 3 oocytes retrieved, and (3) only high-quality blastocysts transferred.

CONCLUSION

The results of this large, multicenter, retrospective study suggested that prolonged cryopreservation was inversely associated with the probability of pregnancy and live birth. Therefore, for patients who adopt a freeze-all strategy, early FET might achieve a better outcome.

Perinatal and maternal outcomes after frozen versus fresh embryo transfer cycles in women of advanced maternal age

OBJECTIVE

The delay of childbearing in women has become a worldwide issue in recent decades. The application of assisted reproductive technology in women of advanced maternal age (AMA) is increasing. Evidence on the safety and outcomes of frozen embryo transfer (FET) compared with fresh embryo transfer (ET) in AMA women is still lacking. Therefore, the objective of the present study was to compare perinatal and maternal outcomes after autologous FET and fresh ET cycles in women of AMA.

STUDY DESIGN

A retrospective study of 1663 FET and 3964 fresh ET cycles in reproductive medical centers from 2009 to 2014. Women who aged ≥35 years and had clinical pregnancies after autologous frozen or fresh ET were included. The main perinatal outcomes included birth weight, gestational age, rates of preterm birth, macrosomia, low birth weight (LBW), and very low birth weight. The main maternal outcomes included rates of hypertensive disorders of pregnancy, gestational diabetes mellitus, and preterm premature rupture of the membranes.

RESULTS

Women who underwent FET had an increased risk of hypertensive disorders of pregnancy [1.1 % vs. 0.4 %, adjusted OR (95 % CI): 2.76 (1.39-5.51); p = 0.004]. Singletons born after FET had significantly higher mean birth weight (3388.78 ± 538.47 vs. 3316.19 ± 549.08; p = 0.001). Furthermore, increased risk of macrosomia [13.5 % vs. 10.4 %, adjusted OR (95 % CI): 1.35 (1.07-1.71); p = 0.013] and decreased risk of LBW [3.6 % vs. 5.3 %, adjusted OR (95 % CI): 0.67 (0.45-1.00); p = 0.048] were found in singletons born after FET.

CONCLUSIONS

Perinatal risks of AMA patients are higher in FET than in fresh ET, including higher birth weight, risks of macrosomia in singleton births, and hypertensive disorders of pregnancy.