Mode of conception does not appear to affect placental volume in the first trimester

Fetal Growth Velocity according to the Mode of Assisted Conception

INTRODUCTION

Pregnancies conceived through assisted reproductive techniques (ARTs) are on the rise worldwide and have been associated with a higher risk of placental-related disease in the third trimester.

METHODS

A cohort was created of singleton pregnancies after assisted reproduction, admitted at our institution for delivery, between January 2020 and August 2022. Fetal growth velocity from the second trimester to delivery was compared against a gestational-age-matched group of pregnancies spontaneously conceived according to the origin of the selected oocyte (i.e., autologous vs. donated).

RESULTS

125 singleton pregnancies conceived through ART were compared to 315 singleton spontaneous conceptions. Overall, after adjusting for possible confounders, multivariate analysis demonstrated that ART pregnancies had a significantly lower estimated fetal weight (EFW) z-velocity from the second trimester to delivery (adjusted mean difference = -0.002; p = 0.035) and a higher frequency of EFW z-velocity in the lowest decile (adjusted OR = 2.32 [95% CI, 1.15-4.68]). Also, when ART pregnancies were compared according to the type of oocyte, those conceived with donated oocytes showed a significantly lower EFW z-velocity from the second trimester to delivery (adjusted mean difference = -0.008; p = 0.001) and a higher frequency of EFW z-velocity in the lowest decile (adjusted OR = 5.33 [95% CI, 1.34-21.5]).

CONCLUSIONS

Pregnancies achieved through ART exhibit a pattern of lower growth velocity across the third trimester, especially those conceived with donated oocytes. The former represents a sub-group at the highest risk of placental dysfunction that may warrant closer follow-up.

The impact of the origin of surgical sperm retrieval on placental and embryonic development: The Rotterdam Periconception cohort

BACKGROUND

In patients with azoospermia, pregnancy can be achieved after surgical techniques using sperm retrieved from the testis or epididymis, which can impact on DNA integrity and epigenetics. DNA of the fetus and placenta is equally derived from both parents; however, genes important for placental development are expressed from the paternal alleles. Therefore, the origin of sperm may affect fetal and placental development.

OBJECTIVES

To investigate whether first-trimester trajectories of embryonic and placental development of pregnancies conceived after intracytoplasmic sperm injection (ICSI) with testicular sperm extraction (TESE) or microsurgical epididymal sperm aspiration (MESA), are different from pregnancies after ICSI with ejaculated sperm or natural conceptions.

MATERIALS AND METHODS

A total of 147 singleton ICSI pregnancies, including pregnancies conceived after TESE (n = 23), MESA (n = 25) and ejaculated sperm (n = 99), and 380 naturally conceived and 140 after IVF treatment without ICSI were selected from the prospective Rotterdam periconception cohort. Crown-rump length (CRL), embryonic volume (EV), Carnegie stages, and placental volume (PV) at 7, 9, and 11 weeks of gestation were measured using 3D ultrasound and virtual reality technology.

RESULTS

Linear mixed model analysis showed no differences in trajectories of CRL, EV, and Carnegie stages between pregnancies conceived after ICSI with testicular, epididymal, and ejaculated sperm. A significantly positive association was demonstrated for PV between pregnancies conceived after TESE-ICSI (adjusted beta: 0.28(95%CI: 0.05-0.50)) versus ICSI with ejaculated sperm. Retransformation to original values showed that the PV of pregnancies after TESE-ICSI is 14.6% (95%CI: 1.4%-25.5%) larger at 11 weeks of gestation compared to ICSI pregnancies conceived with ejaculated sperm.

DISCUSSION AND CONCLUSION

Here we demonstrate that the first-trimester growth trajectory of the placenta is increased in pregnancies conceived after TESE-ICSI compared to those conceived after ICSI with ejaculated sperm. Findings are discussed in the light of known differences in sperm DNA integrity, epigenetics, and placental gene expression.

The Number of Circulating Fetal Extravillous Trophoblasts Varies from Gestational Week 6 to 20

Cell-based non-invasive prenatal testing (cbNIPT) based on circulating fetal extravillous trophoblasts (fEVTs) has shown to be possible in gestational week (GW) 10–13. Prenatal testing is relevant for a wider time period than GW 10–13, but it is unclear if fEVTs are present in sufficient numbers for cbNIPT at other time points during pregnancy. We present the first longitudinal study where the number of circulating fEVTs was determined from the mid first trimester to the mid second, specifically GW 6–8, 12–13, and 19–20. Blood samples from 13 women opting for assisted reproduction were collected at GW 6–8, 12–13, and 19–20. fEVTs were enriched using a magnetic-activated cell sorting system, stained with anti-cytokeratin antibodies, and fEVTs were identified with the use of a MetaSystem fluorescence microscope scanner. Blood samples drawn at GW 6–8 yielded an average of 5.5 fEVTs per 30 mL of blood. This increased significantly to an average of 11.8 in GW 12–13 (P value: 0.0070, Mann-Whitney test), and decreased significantly to an average of 5.3 in GW 19–20 (P value: 0.0063, Mann-Whitney test). In 9 out of 13 cases, the number of fEVTs peaked in GW 12–13 compared to GW 6–8 and GW 19–20. For the majority of cases, fEVTs can be identified at GW 6–8 and GW 19–20, but the highest number of fEVTs is observed at GW 12–13 indicating this is the optimal time point for cbNIPT.

Placental volume and other first-trimester outcomes: are there differences between fresh embryo transfer, frozen-thawed embryo transfer and natural conception?

RESEARCH QUESTION

Does mode of conception influence placental volume and other first-trimester outcomes?

DESIGN

This retrospective single-centre case-control study led in Dijon University Hospital included 252 singleton pregnancies (84 IVF with either fresh embryo transfer or frozen-thawed embryo transfer [FET] and 168 natural conceptions). First-trimester placental volume, uterine artery pulsatility index and maternal serum PAPP-A and beta-HCG were measured. Statistical analyses were adjusted for gestational age, the newborn's gender, maternal age, parity, body mass index and smoking status.

RESULTS

Placental volume was significantly greater in the FET group than in the control group (P = 0.043) and fresh embryo transfer (P = 0.023) groups. At birth, fresh embryo transfer newborns were significantly smaller than controls (P = 0.01) and FET newborns (P = 0.008). Postpartum haemorrhage was far more frequent in FET than in controls and fresh embryo transfer group (38.1%, 2.6% and 1.9%, respectively; P < 0.0001). Placental volume positively correlated with PAPP-A, beta-HCG and the newborn's birth weight, and negatively correlated with uterine artery pulsatility index.

CONCLUSIONS

Placental volume and other first-trimester parameters are modified by IVF with fresh embryo transfer and FET compared with natural conception, but with opposite trends. Given the different protocols used for these techniques, hormonal treatment per se may have a major effect on pregnancy outcomes through the modification of placental invasiveness.

Mode of conception does not affect fetal or placental growth parameters or ratios in early gestation or at delivery

PURPOSE

Ratio of fetal weight to placenta size varies by mode of conception (fertility treatments utilized) in animals. Our objective was to assess whether fertility treatments also affect these ratios in humans.

METHODS

In this retrospective study, we assessed two cohorts: (a) early gestation cohort, women with singleton pregnancies who underwent first trimester vaginal ultrasound and (b) delivered cohort, women who delivered a live-born, singleton infant with placenta disposition to pathology. Crown rump length (CRL) and estimated placental volume (EPV) were calculated from first trimester ultrasound images using a validated computation. Infant birth weight (BW), pregnancy data, placental weight (PW), and placental histopathology were collected. Fetal growth-to-placental weight ratios (CRL/EPV; BW/PW) and placentas were compared by mode of conception. Linear regression was used to adjust for confounding variables.

RESULTS

Two thousand one hundred seventy patients were included in the early gestation cohort and 1443 in the delivered cohort. Of the early gestation cohort (a), 85.4% were spontaneous conceptions, 5.9% Non-IVF Fertility (NIFT), and 8.7% IVF. In the delivered cohort (b), 92.4% were spontaneous, 2.1% NIFT, and 80 5.5% IVF. There were no significant differences between fetal growth-to-placental weight parameters, ratios, and neonatal birth measurements based on mode of conception. Placenta accreta was significantly higher in the patients receiving fertility treatments (1.2 versus 3.6%, p < 0.05).

CONCLUSIONS

Mode of conception does not appear to influence fetal growth-to-placental weight ratios throughout gestation. In addition, findings in animal models may not always translate into human studies of infertility treatment outcomes.

Abnormal Placentation Associated with Infertility as a Marker of Overall Health

Infertility and fertility treatments utilized are associated with abnormal placentation leading to adverse pregnancy outcomes related to placentation, including preterm birth, low birth weight, placenta accrete, and placenta previa. This may be due to the underlying genetics predisposing to infertility or the epigenetic changes associated with the fertility treatments utilized, as specific disease states leading to infertility are at increased risk of adverse outcomes, including placental abruption, fetal loss, gestational diabetes mellitus, and outcomes related to placentation, as well as the treatments utilized including in vitro fertilization (IVF) and non-IVF fertility treatment. Placentation defects, leading to adverse maternal and fetal outcomes, which are more pronounced in the infertile population, occur due to changes in trophoblast invasion, vascular defects, changes in the environmental milieu, chronic inflammation, and oxidative stress. These similar processes are recognized as major contributors to lifelong risk of cardiovascular and metabolic disease for both the mother and her offspring. Thus, abnormal placentation, found to be more prevalent in the infertile population, may be the key to better understand how infertility affects overall and long-term health.